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Discuss findings of studies involving animal histology for GTR using barrier membranes. Is true regeneration (new bone, cementum, and PDL) possible and/or predictable? Discuss the advantages and disadvantages of using resorbable and non-resorbable membranes.
Non-resorbable
Nyman S, et al: The regenerative potential of the periodontal ligament. An experimental study in the monkey. J. Clin. Periodontol 9:257-265, 1982.
Caton JG, et al. Periodontal regeneration via selective cell repopulation. J Periodontol 58:546- 1987.
Resorbable
Magnusson I, et al. New attachment formation following controlled tissue regeneration using biodegradable membranes. J. Periodontol. 59:1-6, 1988.
Pfeifer J, van Swol R, Ellinger R. Epithelial exclusion and tissue regeneration using a collagen membrane barrier in chronic periodontal defects: A histologic study. Int J Perio Rest Dent 9: 263-273, 1989.
Caffesse R, Nasjleti C, Morrison E, Sanchez R. Guided tissue regeneration: Comparison of bioabsorbable and non-bioabsorbable membranes. Histologic and histometric study in dogs. J Periodontol 1994;65:583-591
Wang H-L, MacNeil RL. Guided tissue regeneration. Absorbable barriers. Dent Clin NA 1998; 42:505-522. (Review)
What are the different factors that can affect the outcome/ success of GTR?
Selvig KA, Kersten BG, Wikesjo UME. Surgical treatment of intrabony periodontal defects using expanded polytetrafluoroethylene barrier membranes: Influence of defect configuration on healing response. J Periodontol 1993; 64: 730-733.
Tonetti MS, Pini-Prato G, Cortellini P. Periodontal regeneration of human intrabony defects. IV. Determinants of healing response J Periodontol 1993; 64:934-940.
Tonetti MS, Pini Prato G, Cortellini P. Factors affecting the healing response of intrabony defects following guided tissue regeneration and access flap surgery. J Clin Periodontol 1996; 23:548-556.
Selvig K, Kersten B, Chamberlain A, Wikesjo U, Nilveus R. Regenerative surgery of intrabony periodontal defects using ePTFE barrier membranes: Scanning electron microscopic evaluation of retrieved membranes versus clinical healing. J Periodontol 1992; 63: 974-
Ling L-J, Hung S-L, Lee C-F, et al. The influence of membrane exposure on the outcomes of guided tissue regeneration: clinical and microbiological aspects. J Periodont Res 2003;38:57-63.
Anderegg CR, Metzler DG, Nicoll BK. Gingiva thickness in guided tissue regeneration and associated recession at facial furcation defects. J Periodontol 1995;66:397-402.
Cortellini P, Tonetti MS Improved wound stability with a modified minimally invasive surgical technique in the regenerative treatment of isolated interdental intrabony defects.J Clin Periodontol. 2009 Feb;36(2):157-63
Cortellini P1, Labriola A, Tonetti MS. Regenerative periodontal therapy in intrabony defects: state of the art. Minerva Stomatol. 2007 Oct;56(10):519-39.
Discuss findings of studies involving human histology for GTR using barrier membranes.
Nyman S, et al: New attachment following surgical treatment of human periodontal disease. J. Clin Periodontol 9:290-296, 1982.
Gottlow J, Nyman S, Lindhe J, Karring T, Wennstrom J.: New attachment formation in the human periodontium by guided tissue regeneration. Case reports. J Clin Periodontol 13:604-616, 1986.
Stahl SS, Froum S, Tarnow D. Human histologic responses to guided tissue regenerative techniques in intrabony lesions. J Clin Periodontol 1990; 17: 191-198
Has GTR proven to improve clinical results in infrabony defects? Discuss the determinants of success of GTR reported in the literature. Discuss postoperative complications of GTR procedures.
Becker W, Becker BE: Treatment of mandibular 3-wall intrabony defects by flap debridement and expanded polytetrafluoroethylene barrier membranes. Long-term evaluation of 32 treated patients. J Periodontol 1993; 64:1138-1144.
Cortellini P1, Pini Prato G, Tonetti MS. Periodontal regeneration of human infrabony defects. I. Clinical measures. J Periodontol. 1993 Apr;64(4):254-60.
Cortellini P, Pini Prato G, Tonetti MS. Periodontal regeneration of human infrabony defects. Part II. Re-entry procedures and bone measures. J Periodontol 1993; 64:261-268.
Tonetti MS1, Pini-Prato G, Cortellini P Periodontal regeneration of human intrabony defects. IV. Determinants of healing response. J Periodontol. 1993 Oct;64(10):934-40.
Cortellini P, Pini Prato G, Tonetti MS: Periodontal regeneration of human intrabony defects with titanium reinforced membranes. A controlled clinical trial. J Periodontol 1995,66:797-803.
Caton J, Greenstein G, Zappa U. Synthetic bioabsorbable barrier for regeneration in human periodontal defects. J Periodontol 1994;65:1037-1045
Laurell L, Falk H, Fornell J, Johard G, Gottlow J. Clinical use of a bioresorbable matrix barrier in guided tissue regeneration therapy. Case series. J Periodontol 1994;65:967-975
Cortellini P, Pini Prato G, Tonetti MS: Periodontal regeneration of human intrabony defects with bioresorbable membranes. A controlled clinical trial. J Periodontol 1996, 67:217-223.
Christgau M, Schmalz G, Wenzel A: Periodontal regeneration of infrabony defects with resorbable and non-resorbable membranes: 30 month results. J Clin Periodontol 1997; 24:17-2
Evans GH, Yukna RA, Cambre KM, Gardiner DL. Clinical regeneration with guided tissue barriers. Curr Opinions in Periodontol 1997;4:75-81. (Review)
Needleman IG, Worthington HV, Giedrys-Leeper E, Tucker RJ.Cochrane Database Syst Rev. Guided tissue regeneration for periodontal infra-bony defects. 2006 Apr 19;(2):CD001724
Murphy K. Postoperative healing complications associated with Gore-Tex Periodontal Material. Part I. Incidence and characterization. Int J Perio Rest Dent 1995:15:363-375.
Murphy K. Postoperative healing complications associated with Gore-tex Periodontal Material. Part II. Effect of complications on regeneration. Int J Perio Rest Dent 1995;15: 549-561.
Murphy KG1, Gunsolley JC. Guided tissue regeneration for the treatment of periodontal intrabony and furcation defects. A systematic review. Ann Periodontol. 2003 Dec;8(1):266-302.
Discuss findings of studies involving animal histology for GTR using barrier membranes. Is true regeneration (new bone, cementum, and PDL) possible and/or predictable? Discuss the advantages and disadvantages of using resorbable and non-resorbable membranes.
Non-resorbable
Purpose: To study the cellular kinetics in the PDL and alveolar bone adjacent to periodontal wounds with “periodontal spaces” created by physical barriers.
Materials and methods: 4 adult monkeys were used. Teeth were scaled and polished, plaque controlled was maintained for two weeks and surgical wounds were created.
Small fenestration wounds (3x3mm) were made with a round bur at the middle third of the root after full thickness flap reflection. The exposed root surface was planed to remove PDL and cementum. A Millipore filter was used to cover the roots and the flaps were then replaced and sutured. The teeth were divided in six groups and in left and right side. The wounding in this segments was planned to provide observation periods of 1h, 1, 2, 3, 7 and 21 days.
Animals were sacrificed and block sections were obtained for histologic and autoradiographic analysis.
From the apical part of the wound, three 100μm zones coronally into the wound and apically into the intact periodontium were examined. The lingual PDL was examined at the same apicocoronal level as a controlled undisturbed PDL. Fibroblast – like labeled cells (IV administration of thymidine) number was calculated.
Results: 1hr specimen: blood clot, root planing had resulted in complete removal of PDL and cementum
1-day wounds: large blood clot, inflammatory cells, a few paravascular cells in the adjacent PDL and some endosteal cells in the bone compartment were labeled
2-day wounds: more organized fibrin network in the wound proper and an increase in the number of labeled cells in the adjacent PDL and bone compartments
3-day wounds: cell migration into the wound was clearly evident and cells appeared to arise from both PDL and bone
7-day wounds: decrease in the label uptake by cells in the PDL compartment while the bone cells showed a slight increase. Labeled cell were seen in all 3 wound comparments
21-day wounds: very few labeled cells which showed islands of new bone formation and some cementum in the apical half of the wound. One specimen showed root resorption in the central part of the wound.
The effects of time, compartment, zone and their interactions were all significant. Peak activity was 2 days for the PDL. Bone had 2 peaks of activity, at 2 days and 7 days, with labeled cells appearing at the wound edge at day 3. Mitotic activity was maintained in all compartments up to day 7 and then began to decline.
Conclusion: Both bone and PDL compartments are potential sources of cells migrating into experimental periodontal wounds with periodontal spaces. From this study it is unclear whether it’s the PDL , bone or both cell types that have the potential to form new cementum with inserting collagen fibers.
Purpose: To examine if new cementum and new attachment may form during healing of a wound prepared in such a way that preference is given to PDL cells to repopulate the wound area.
Materials and methods:
3 adult Macaca monkeys had maxillary laterals and mandibular canines selected for experimentation.
FTF was raised. Buccal and interproximal bone was removed from the mid root to 2mm apical to marginal bone crest.
Root surface was curetted to remove all cemenum Notches delineated denuded root portion.
A Millipore filter 0.22 microns was placed over the treated area to prevent gingival CT from contacting root surface during healing. Animals were sacrificed at 6 months. Histo analysis conducted.
Results:
New cementum with inserting collagen fibers was observed on curetted root surfaces; however, results of healing did not consistently occur along entire length of curetted portion.
The cementum formation had always occurred within the apical notch and extended coronally to a distance varying between 25-100%.
In 50% of the specimens, the cementum did not reach coronal notch, which suggests that cementum formation must have originated in apical portion of the wound. Coronal portion characterized by CT adhesion to root surface without cementum formation and fibrous attachment. The coronal alveolar bone resorbed probably due to lack of blood supply.
BL: Results suggest that PDL cells possess ability to form cementum and reestablish CT attachment. This is not a predictable result (25 100%) even when PDL cells are preferentially allowed to populate the defect.
P: To determine the histogenesis and the chronological sequence of events leading to regeneration via selective cell repopulation of the root surface in the squirrel monkey model.
M&M: 6 squirrel monkeys were used. Semilunar incision was made 10-12 mm apical to the free gingival margin of canine and a FTF was reflected towards the mucogingival junction. Bony fenestrations were created on the facial bone of canines. Root planning of all fibers and cementum was performed. The experimental wounds received Millipore filters while control group was covered by the flap only. Flaps were repositioned & animals were sacrificed at 3, 7, 14, & 35 days.
R: Clinical observations were similar in both groups & healing was uneventful. Histology: 3d: clot of RBC enmeshed in fibrin occupied the fenestration and attached to the root surface. 7d: some bone resorption at PDL surface of bone; marrow spaces near fenestration showed osteogenesis. 14d: all specimens had regeneration: new cementum, bone, some ankylosis (10-15%). Equal amounts of bone was seen in both groups (42.8% in control, and 47.6% in experimental). PDL at early stage & new collagen fibers parallel to the root planed area. 35d: Differences became apparent. New cementum on 36.1% of root planed surfaces vs. 75.6% on experimental sites. New bone formation 42.8% in controls (same as day 14) vs. 86.1% of experimental. Less ankylosis was seen in experimental.
New Cementum, Bone and Ankylosis Observed at 35 Days
|
Cementum |
Bone |
Ankylosis |
|
|
Control |
36.1% |
48.7% |
8.9% |
|
Experimental |
75.6% |
86.1% |
0.2% |
D: Bone formation preceded cementum formation at 14 & 35 days. The fenestration was almost completely regenerated with the new cementum, bone & immature PDL connecting the tooth. Limited regeneration was seen in control. Root resorption & ankylosis were also seen in both groups.
BL: Bony fenestrations regenerated almost completely by 35 days when gingival connective tissue cells were occluded, while those treated with flap only showed a moderate regeneration with maximum at 14 days. This study is the basis for removing the membrane at 4-6 weeks.
Purpose: To evaluate the use of a newly developed biodegradable, polylactic acid membrane during healing of surgical defects in dogs.
Materials and methods: Two dogs were used in the study. Mucoperiosteal flaps were elevated on the buccal of 2nd, 3rd and 4th premolars of all 4 quads. Along one root in each of these 3 teeth, buccal and proximal alveolar bone was removed to approximately 25% of its original level. Roots were planned to remove cementum. Membrane was used to cover the defects. In 8 teeth a Millipore filter was used and in 8 the polylactic acid membrane was used. The remaining 8 teeth did not receive membranes and served as controls. After 2 months animals were sacrificed and histologic analysis was performed. CEJ- apical level of root planning (aRP), aRP-coronal level of newly formed cementum (cC), aRP-bone crest (BC) and CEJ-gingival margin (GM) were measured.
Results:
All of the roots covered with polylactic acid membrane exhibited a newly formed thin cementum layer with inserting collagen fibers and newly formed bone. The length of the newly formed CT was 2.5mm on average corresponding to 46% of the curetted surfaces.
The roots covered by Millipore filters were characterized by significantly less new attachment and bone. CT attachment of 1.4mm (25% of planned areas) was observed in 6/8 roots. Regrowth of bone was 1.7mm.
The control roots only minor new attachment was found in the bottom of the defect in some roots. (0.7mm, 12% of the instrumented root surface).
Conclusion: Membranes used in this study were designed to degrade in 3-4 months. From the results it seems that a degradation time of 2 months would be sufficient. The use of biodegradable membranes in regeneration procedures is still to be considered as experimental and further development is needed.
Pfeifer 1989 NO ARTICLE
Purpose: To evaluate the effectiveness of resorbable collagen barriers in blocking the downgrowth of epithelium into perio surgery wounds.
Materials and methods:
Cross linked and non Cross linked collagen membranes were prepared from purified soluble bovine dermal collagen.
4 beagle dogs.
Grade II furcation involvement were created on the buccal of 4 1st molars in each dog.
A wire ligature was used in the furcations for 12 weeks to create chronic inflammation. Two weeks after wire removal, surgery was performed; membranes were placed at test sites and no membranes at control sites. Dogs were killed at 1, 3, 4, & 8 weeks post-op.
Results:
12 test sites (6 cross linked & 6 non cross linked membranes) and 4 control sites
1 week: significant tissue proliferation between cross linked membrane and bone. The non cross linked membrane lost their structural integrity and showed partial resorption with little tissue proliferation.
3 weeks: cross linked membranes still present, non cross linked membranes not detectable and healing in this areas was similar to control.
4 weeks: cross linked membranes present, appositional bone formation and new cementum seen. No epithelial downgrowth and all histologic sections showed evidence of regeneration, especially in the apical 2/3 of the defect. The healing of non cross linked membranes sites was similar to controls.
8 weeks: cross linked membrane sites continued to show regeneration and the membrane was mostly resorbed. The controls showed disorganized healing pattern with little or no bone, cementum, or PDL formation.
Conclusion: Cross linked collagen membrane is preferred over non cross linked membranes. Non-cross-linked is totally resorbed in 3 weeks. Cross-linked ones will persist as intact barriers for 6-8 weeks and have the capacity of preventing epithelial downgrowth.
P: To examine the histologic and histometric responses to 2 bioabsorbable membranes (type I, II) made from a synthetic copolymer of glycolide and lactide and compare them to ePTFE. And also to evaluate whether the two membranes were present and intact at 1 month and completely degraded at 3 or 6 months.
M&M: 9 adult fox hound dogs with no periodontal disease were included. After being housed for 2 weeks, the dogs were sedated and SRP performed. Plaque control was maintained by topical applications of a 0.12% CHX soln and prophy every other week. 2 weeks following root instrumentation, animals were anesthetized, buccal and lingual FTFs were reflected in the mandibular premolar areas. Randomly selected, the buccal alveolar bone was reduced on one quadrant on the 2nd and 4th premolars to a level approximately 5 to 8 mm apical to the CEJ creating a Class II buccal furcation defect, while the other quadrant received a Class II buccal defect only on the 4th premolar. The exposed root surfaces were thoroughly denuded of PDL and cementum and notches were placed at the new bone level of each root. One site received the bioabsorbable Type I barrier, and the other site received the bioabsorbable Type II barrier .The contralateral quadrant received ePTFE on the 4th premolar and was used as control site. The buccal and lingual flaps were positioned slightly coronally and sutured. Sutures were removed 1 to 2 weeks after surgery. Abx was administered for 3 days post-op. 1 month post-op, 3 dogs were sacrificed. At this time, a 2nd surgical procedure was performed in each of the remaining 6 dogs to remove the ePTFE. Of these 6 dogs, 3 were sacrificed at 3 months post-op and the other 3 at 6 months after surgery. Histology and histometric analysis were performed.
R: New cementum with inserting CT fibers had deposited on the denuded portion of the roots. Alveolar bone regeneration had occurred on both test and control specimens. There were histologic differences between the ePTFE treated teeth (control) and the two bioabsorbable membrane treated teeth at 1 month following surgery in degree of induced inflammation, and rate and quality of healing.
1 Month: teeth that received the ePTFE showed no inflammatory cells, new cementum with inserting collagen fibers and varying amounts of new alveolar bone. Those teeth that received either of the bioabsorbable membranes showed early resorption of the membranes, minimal inflammatory reaction and no mature connective tissue.
3 and 6 Months: specimens revealed increasing amounts of CT regeneration, cementogenesis, and alveolar bone deposition resulted from the use of both bioabsorbable and non-bioabsorbable membranes. No relationship was found between the amount of new cementum deposition and the degree of bone formation. Small remnants of the bioabsorbable membranes were depicted in these specimens. Histometric analysis showed no major differences in the results of healing between specimens of roots treated with the non-bioabsorbable barrier (control) and roots treated with either of the bioabsorbable membranes.
D: All 3 membranes tested were effective in not only preventing apical migration of the epithelium, but also guiding the ingrowth of PDL cells into the healing periodontal wound, resulting in new CT attachment.
BL: Similar results can be achieved in GTR procedure with bio-absorbable or non-bioabsorbable ePTFE membranes.
Guided tissue regeneration. Absorbable barriers
P: to discusses (1) principles of guided cell population and GTR, (2) Indications and contraindications for barrier techniques, (3) the clinical procedure, and (4) pros and cons of different types of absorbable barriers currently being used or tested in periodontal practice
Principles of guided cell population and GTR
GTR: procedures wherein regeneration of lost periodontal structures (cementum-PDL-alveolar bone) is sought via selective cell and tissue repopulation of the periodontal wound. Barrier techniques are employed to exclude dental tissues with little or no regenerative capacity (gingival epithelium-corium).
Indications and contraindications for Barrier procedures
Patient selection*** healthy, nonsmoker, good plaque control, and compliance
Specific defects/problems that demonstrate optimal regenerative healing after GTR
Narrow 2-wall or 3-wall infrabony defects with at least 4mm of ALoss, 4mm infrabony component
Circumferential defects
Class II furcation w/ med to long root trunk
INDICATIONS: ridge augmentation, root recession coverage, repair of apicoectomy defects, osseous fill around immediate implant placement sites, and repair of osseous defects associated with dialing implants (NOT FDA APPROVED)
Not recommended to pt with poor OH, generalized horizontal bone loss, class III furcation, advanced periodontal disease with an inadequate zone of attached gingiva.
Clinical procedure
Before procedures, good plaque control (<15% tooth surfaces), Post-op period, Good OH with follow up visits (1, 2, 4, 6, and 8 weeks post-op)
Selvig 1993 ARTICLE clinical results
P: To evaluate the influence of crestal and subcrestal defect morphology on healing in intrabony periodontal defects treated by membrane (e-PTFE) supported reconstructive flap surgery.
M+M: 26 intrabony defects in 23 systemically healthy patients were treated with OFD and e-PTFE membranes. In 12 defects root surface was conditioned with citric acid for 3 min. Membrane was removed surgically after 4-6 wks. Healing evaluated by probing and bone sounding 12 months post-op.
R: Mean PD reduction was 1.8 mm, CAL gain 0.8 mm and bone level change 1.2 mm- all were SSD. PD reduction, CAL gain, and bone fill were positively correlated to the depth of the 3-wall intrabony component of the defect. These parameters improved the most in the 3-wall defect (1-2 wall defects didn’t show a significant correlation). The extent of crestal involvement, number of surfaces involved and wall form in the fundus of the defects didn’t influence the healing response. Citric acid tx didn’t enhance healing compared to membrane only. Defects with greatest PD showed the greatest PD reduction and CAL gain. There was a slight CAL and bone loss for the teeth adjacent to the defects, and SS recession.
BL: Healing pattern following barrier membrane supported flap surgery (GTR) appears similar to that generally observed for conventional reconstructive flap surgery in intrabony defects.
Cr: Included results of 1,2 and 3 wall defects (predominant 2 wall). Evaluated only at one time, not periodically. Ended up with deep pockets after treatment.
P: To identify clinical events and situations that can affect and enhance the predictability of GTR in deep intrabony defects.
M&M: 40 intrabony defects treated with GTR in 23 patients (18-56 years old). Teeth had IP vertical defects with probing attachment levels (PAL) of >6mm with radiographic evidence of an intrabony defect. Phase 1 treatment (SRP, OHI) was completed, three months later clinical measurements (BOP, PD, REC, PAL) were taken and one week later surgery was performed. Teeth treated with e-PTFE and CPF. Pt asked to rinse twice daily with 0.2% CHX until membrane removed at 4-6 weeks. Patients were recalled every month for 1 year. Re-entry operations were performed to evaluate bone healing. The distance between the CEJ and the most coronal extension of the regenerated tissue (newly formed granulation tissue, NFGT) was recorded to the nearest mm.
R: 35% had lack of complete membrane coverage. 73% membrane exposure. At membrane removal, tissue gain of 7+2.2mm. The deeper the defect, the greater the tissue gain, and the wider the width, the lower the gain. At 1 year, PAL gain was 5.6 +2.6mm. The higher the 1 year BOP, the lower PAL gain. At 1 year, bone fill was 4.3+2.5mm.
B/L: Wider defect angle, less tissue gain. Lack of good coverage of tissue after membrane removal resulted in decrease about 2mm of regenerated PAL and bone fill. Infection control, measured as full mouth bleeding, significantly affected the tissue maturation process.
Purpose: To identify and compare the significant factors associates with the healing outcomes of intrabony defects treated with: a) GTR procedure with self-supporting membranes (e-PTFE) and the modified papilla preservation technique, b) a conventional GTR procedure with non-resorbable membranes (e-PTFE) and c) an access flap procedure (MWF).
Materials and methods: The defects were randomly assigned to the above treatment modalities after controlling for 2 prognostic factors: depth of the infrabony component (INFRA)
and probing attachment level (PAL). 45 patients were recruited and had a deep infrabony defect in the IPx areas.
Full mouth plaque scores (FMPS), BOP, full-mouth bleeding scores (FMBS), PD, recession and PAL were recorded by one investigator one week before the surgical procedure and at one year follow-up.
Intra-surgical measurements: CEJ-base of the defect (BD), CEJ – coronal part of the defect (BC) and depth of 1-, 2- and 3- wall components.
Membranes were removed at 6 weeks and before membrane removal the distal between the CEJ and the position of the membrane (MEM) was measured and after the removal the distance between the CEJ and the newly formed granulation tissue (NEGT) was recorded. Flaps were sutured again and OH with IPx cleaning was allowed at that time. Patients had monthly prophylaxis up to the 1-year re-evaluation.
Results: 6 subjects were smokers (more than 10 cigarettes/day). NSSD between baseline measurements for all three groups.
There was a SSD in space available for tissue formation under the membrane: 9.4(Group A) & 7.9(Group B). Tissue gain was SSD: 8.1(Group A) & 7.4 (Group B). The most significant factor for tissue gain under a membrane was the amount of space available for regeneration under it.
SSD differences in 1-year PAL gain were observed comparing the 3 groups. Group A: 5.3mm, Group B: 4.1mm and Group C: 2.5mm. No SSD in PD reductions among the three groups.
Factors that affected 1-year gain: the greater the CEJ-bone crest and the greater the amount of tissue gained under the membrane the greater the PAL gain at 1 year. The greater the suprabony component of available space and the greater the FMPS, the smaller the expected gain.
Conclusion: Results indicated that: (i) the need to create and maintain space should be a key objective of regenerative approaches based upon the principles of GTR; (ii) control of patients’ OH and residual periodontal infection in the oral cavity are strongly associated with clinical outcomes of both regenerative and conventional surgical procedures
Purpose: To compare the condition of the membrane at the time of removal to the clinical efficacy of membrane supported reconstructive surgery in intrabony periodontal defects.
Materials and methods:
12 pts that were systemically healthy (23 84 yo): 16 intrabony defects w/PDs 5.5 11.3 mm, and >4 mm defect depth. 1, 2, and 3 wall defects were included. OFD, ePTFE membranes placed over the defects, and gingival flaps repositioned.
In 4 cases, root surface conditioning w/ citric acid for 3 min was done.
TTC 250 mg qid for 2 weeks, 0.12 % chlorhexidine for 6 8 weeks, membranes removed 4 6 weeks postop.
Prophy every 3 months. 12 month post-op healing was evaluated by clinical AL and bone level assessment (no reentry).
Retrieved membranes were evaluated by scanning electron microscope (SEM).
Results:
Most membranes had 1 2 mm marginal exposure interproximally at the time of removal. SEM showed the majority of membranes had bacterial deposits marginally (cocci, filaments, and short curved rods, no spirochetes).
PAL varied from a loss of 2.3 mm to a gain of 3.5 mm and probing bone level ranged from 1.0 to +4.3 mm.
There was a significant negative correlation b/w the extent of membrane contamination and gain in PAL (more membrane contamination less gain in PAL).
BL: Extent of oral exposure and bacterial contamination of the e-PTFE membrane may be an indicator of the long-term success or failure of the regenerative procedure.
P: To evaluate the influence of membrane exposure on guided tissue regeneration (GTR).
M&M: 30 2-wall or 3-wall infraosseous defects were treated with GTR. Bone grafts were used in combination with ePTFE membranes. PI, GI, BOP, PD, CAL and recession were assessed at the baseline examination, as well as immediately prior to and six months after GTR. Exposure of the membrane was observed by visual examination at weekly recall visits. The membrane was removed 6 weeks after GTR procedure. The numbers of Pg and Aa on the retrieved e-PTFE membranes were assessed using PCR.
R: Membrane exposure noted in 19 sites (63.3%), usually 2 weeks after the sx. Membrane exposure was found in 100% of the smokers (8/8), while only 50% (11/22) of the non-smokers had membrane exposure. 26.3% of the membrane exposure sites had zero attachment gain. The membrane exposure sites tended to achieve a smaller clinical attachment gain (but not SS) and had significantly greater marginal tissue recession (1.7 mm recession vs none). The exposed membranes harbored significantly more Aa than the non-exposed membranes (p = 0.029). P.g. was found more often in the exposed group, but it did not reach SS.
BL: Membrane exposure resulted in a less favorable GTR outcome. The amount of Aa on the exposed membrane may be a major contributing factor to the outcome of GTR.
Cr: Even the non-exposed membranes had bacterial contamination. The two groups did not show great clinical differences for any parameter (all differences were less than 1mm).
Purpose: To determine if the thickness of gingiva used to cover a membrane influences development of recession at molar facial furcation defects treated with membranes for GTR.
Materials and methods: 37 patients, mean age of 39 years old with at least one mandibular or maxillary Class I or II furcation. No 3rd molars were included. Initial Tx included plaque control and occlusal adjustment. AL and recession at the midfacial site of the tooth pre-surgically. e-PTFE membranes were used for the GTR and thickness of the gingiva was measured 5mm apical to the coronal margin of the flap. No bone graft was used and no coronally positioning of the flap was performed. Membranes were removed 6 weeks later. Pts were divided in 2 groups depending on the mucoperiosteal flap thickness.
In Group 1 thickness was 1mm or less (16 patients) and in Group 2 more than 1mm (21 patients). At 6 months recession was recorded again. Measurements were standardized.
Results: NSSD between the two groups in presurgical measurements. Group 2 had almost double thickness in gingiva than group 1 (1.44mm vs 0.76mm). After 6 months mean increase in recession from baseline was greater for Group 1 (2.1mm) comparing to Group 2 (0.6mm). 3 times more recession was observed with flap gingival thickness of 1mm or less.
Conclusion: If thin soft tissue covers the defect where a membrane is to be used, recession may occur with greater frequency and magnitude than where thicker tissue exists presurgery.
Purpose: To describe the modified Minimally invasive surgical technique “M-MIST”
Materials and methods
20 intrabony defects in patients with advanced periodontal disease, systemically healthy, presenting at least one isolated deep intrabony defect of at least 3mm and non smokers .
The experimental sites were accessed with M-MIST +EMD, control MIST
Weekly recalls for 6 weeks and then 3month SPT for 1 year. Clinical measurements at baseline and 1 year.
M-MIST, the intrasulcular incision extended to the to the buccal aspect of the adjacent teeth. The supracrestal interdental tissues remained attached to the root cement.
Defect was debrided, granulation and soft tissue removed carefully from under papilla and EMD applied, 6-O or 7-O e-PTFE sutures used to reach primary closure. Procedures performed with the aid of a microscope.
Results
20 intrabony defects, 15 M-MIST, 5 required the elevation of the interdental papilla along with a lingual flap. 15 patients presented for 1 year follow up
M-MIST: The 1-year CAL was 5.1 mm +/- 1mm with a clinical attachment gain of 4.5mm +/- 1.4mm. The differences in CAL between baseline and 1 year SS
Residual PPDs were 3.1 +/- 0.6mm with an average reduction of 4.6 +/- 1.5mm, SS.
Discussion
This surgical approach allows for access and minimization of the flap elevation, enhancing wound stability and healing.
When the defect involves the lingual aspect, root planning is very difficult.
M-MIST associated with EMD resulted in improved clinical outcomes with no or minimal patient morbidity.
P: Review of regenerative periodontal therapy in intrabony defects.
D: Periodontal regeneration is selected to obtain: 1) an increase in the periodontal attachment and bone of a severely compromised tooth; 2) a decrease in pocket depth; 3) a minimal or no increase in gingival recession
Evidence for clinical efficacy: Systematic reviews and Meta-analyses show that the addition of a barrier membrane results in an additional 1mm CAL gain compared to an access flap control. Bone replacement grafts were assessed in systematic reviews showed an additional 0.5 mm CAL gain compared to access flap control. The use of EMD also has been shown to provide benefit, with multicenter trials showing a CAL gain of 0.75 mm.
Patient and defect prognostic factors: Level of control of periodontitis is associated with outcomes: poor plaque control, high levels of BOP, and the persistence of high loads of bacteria (or complexes of pathogens) are associated with poorer outcomes. Smokers have more impaired regenerative response: they have dose dependent detrimental effect on CAL gains. Defect morphology plays a major role as well. The deeper the defect, the greater amount of clinical improvements. The wider the defect the lower the attachment and bone gains. Some studies say 3-wall defects have better outcomes, while others say there is no difference in gain of attachment between 1,2,3-wall defects. RCT therapy on a tooth does not negatively affect healing response or long term stability of deep intrabony defects. Tooth mobility: tooth hypermobility is negatively and dose dependently associated with the clinical outcomes. Teeth with a mobility less than 1mm horizontally can be treated by regeneration.
Surgical Approach: Primary closure over membrane is important to prevent wound dehiscence. Exposed membranes are a problem due to contamination with bacteria. Papilla preservation flaps (ModifiedPPF for interdental space >2mm or SimplifiedPPF if interdental space is <2mm) should be used along with a minimally invasive surgical technique. Use of biologics is also indicated.
Materials for Regenerative Surgery: Non-resorbable and resorbable membranes are used depending on the clinical situation. Bone replacement grafts vary. DFDBA alone gives documented improvements in some intrabony defects (2 and 3 wall defects). Bio-Oss with and without EMD have been used in various studies. EMD and PDGF also applied for enhanced regeneration and wound healing.
Post-Op: Empirical protocol for the control of bacterial decontamination consisting of Doxycycline (100mg BID for 1 week), 0.12% CHX rinse 3x/day, and weekly prophylaxis as needed. Pts should avoid brushing, flossing and chewing in area for period of 6-10 weeks. Pts can resume full OH and normal function in the treated area 2-4 weeks after membrane removal or when bioresorbable membranes are fully resorbed. Pts treated with EMD resume full OH after a period of 4-5 weeks. At the end of the early healing phase, pts placed on monthly recall for 1 year.
Long Term Effects and Benefits of Regeneration: Gotlow et al. evaluated new attachment stability from GTR and found stability can be maintained on long-term basis. Pt factors play a large role. Compliance with OH, smoking habits, and susceptibility to disease progression rather than the employed treatment modality were the major determinants of stability of the treated sites. Other long-term studies show that if the pt maintains SPT interval and good OH, the regenerated attachment can be maintained long-term. Cortellini and Tonetti analyzed tooth survival on a sample of pts followed for 2-16 years. 96% of teeth treated by periodontal regeneration survived (tooth survival 89% among smokers and 100% among non-smokers). CAL were located at the same level or coronal to the pre-treatment levels in 92% of cases up to 14 years after treatment.
Nyman 1982 ARTICLE human histology
P: To examine if previously diseased roots can have new CT attachment if cells from the PDL are allowed to repopulate the root surface
M&M:47 y/o M had advanced perio. Flap was reflected on #23 and notch placed 9mm apical to CEJ and was 2mm coronal to bottom of defect. Area degranulated and RP completed to bottom of the pocket. A millipor filter was placed to cover from 1 mm apical to the crest to 2mm coronal to the CEJ. The filter was attached w/ resin. The buccal and lingual flaps then reapproximated (approx 2mm apical to CEJ). 3mo of healing, then tooth was removed en-bloc together with its buccal periodontium. Biospsy completed.
R:New cementum had formed on the root surface that extended 5mm coronal to the notch. New bone had formed in the bony defect. No bone had formed coronal to the crest.
C: New attachment can occur from PDL cells on previously diseased root surfaces.
P: To evaluate if GTR can predictably result in the formation of a new attachment in human teeth.
M&M: 12 teeth in 10 Pts were used. 5/12 teeth were hopeless and planned for extraction. Of these 5, 4 were treated with GTR (Gore Tex) and 1 without. The remaining 7 teeth were treated with GTR (Gore Tex) and evaluated clinically. Prior to surgery, PD was determined at the surface for regeneration, molars were measured in horizontal and vertical directions into the furcation. FTF were reflected, debridement with hand instruments and diamond burs without osseous. Measured the bone level (BL). Gore Tex membranes were placed extending 5 mm apical to the crest of bone. Flaps were coronally positioned. At 3 months, 5/12 teeth were extracted Block sections were performed and histology was performed. In the remaining 7 teeth the membrane was removed at 3m and the final examination was done after 3m of the removal.
R: I. EXTRACTED teeth:
Case 1: #31 (Lingual) furcation: Complete closure of the defect (no furcations were able to be probed). Newly formed cementum was surrounding the roots.
Case 2: Class III furcation. No regeneration, epithelialized furcation area with 2.8mm of cementum.
Case 3: Bone loss was to level of tooth apex. New attachment formation was 4.5mm. Was temporarily maintained.
Case 4: PAL to the apex; new attachment formed 3.2mm.
II. REMAINING teeth: (Initial PAL ranged from 8-14mm )
Gain in horizontal and vertical PAL from 3-7mm in all cases at 6mos.
D: An important factor for new attach formation is amount of remaining periodontium. Regeneration of alveolar bone is restricted to sites with angular defects. CT attachment can form without concomitant bone formation. Migration rate of PDL cells is at least as high as bone cells (no ankylosis present in this study).
BL: GTR predictably results for new connective tissue attachment.
P: The present histologic healing responses in sites in which barrier membranes were placed for treatment of intrabony defects.
M&M: 9 periodontal defects (1 or 2 walls) on 8 teeth in 5 adult (ages: 29 to 65 years) patients (2 female, 3 male) with severe periodontitis were treated by open debridement flap followed by insertion of one of two types of Teflon membranes (Emflon or Gortex).Prior to surgery, a horizontal notch was made at the level of the gingival margin using a round bur and during surgery a second notch was made through the most apical level of visible calculus and the following measurements made:
distance from calculus notch to the deepest point of the osseous defect;
distance from calculus notch to the alveolar crest.
An intrasulcular incision was made, FTF was elevated, SRP was performed .At random, 1 of 2 different Teflon (PTFE) membranes was chosen to be used following debridement of the defect. Barrier membranes were placed coronal to the gingival notch and at least 5mm apical to bone crest. Flaps were coronally positioned and patients were placed on 0.12% CHX for 2wks post-op. Block sections were removed 5 to 30 weeks after membrane placement. Prior to surgery and at the time of block removal, clinical records, measurements, photographs and radiographs were taken. In order to observe early healing responses, 6 sites were harvested 5 to 8 weeks after surgical treatment. 3 additional sites were removed 14, 22 and 30 weeks respectively after surgical treatment.
R: Histologically, new cementum was seen in a linear direction along root surfaces in 6 out of 9 sites (length of cementum = 0.5 to 1.7 mm). 3 sites showed no evidence of new attachment. At sites of cementogenesis, functionally-oriented fibers were inserted. Regenerative responses were seen with both types of Teflon membranes and were present as early as 5 weeks after surgery.
BL: These cases do not indicate predictability of results but support the concept that a physical barrier may delay epithelization of the root long enough to allow progenitor cells from the attachment tissues to colonize previously denuded root surfaces and form new attachment. This process occurs in the early stages of healing (5 week responses).
Becker 1993 ARTICLE clinical results
Purpose: To report the findings on intrabony defects treated by GTR and followed for extended time intervals.
Materials and methdos: 32 patients with 33 intrabony defects treated with OFD and ePTFE membrane treatment of mandibular 3-wall intrabony defects >5mm in depth. The distances CEJ-base of defect and CEJ – bone crest were recorded.
All patients received OHI and SRP prior surgery except in areas for GTR therapy to avoid recession. After surgery tetracycline HCL was given at a dose of 1gram per day for 1 week. Membranes were removed at 4-6 weeks. Re-examination occurred at an average of 3 years 5 months. 24 patients had re-entry at the 2nd examination. 16 of these were examined at a 3rd time at an average of 4 years 3 months. Each examination included PD, CAL, recession, and crestal resorption and defect bone fill (at re-entry).
Results: Between Exams 1 and 2 there was a SS reduction of pocket depth, gain in clinical attachment level, and an increase in recession. For the 24 patients who had re-entry procedures there was an average defect fill of 4.3 mm and 0.33 mm of crestal resorption.
|
Examination |
PD |
CAL |
Recession |
|
Baseline |
9.79 |
9.81 |
-0.03 |
|
Exam 2 (Re-entry) |
3.61 |
5.25 |
-1.29 |
|
Exam 3 |
3.98 |
5.68 |
-1.01 |
Conclusion: Results suggest that deep 3 wall intrabony defects treated by OFD/ePTFE had a clinically significant reduction in PD, gains in CAL, and gains in bone fill.
Purpose: To evaluate the extent and predictability of probing attachment level (PAL) gains following GTR treatment in deep infrabony defects.
Materials and methods:
23 pts in good health, good OH, no systemic meds, NKDA, and presence of a deep angular bony defect (1, 2, and 3 wall defects).
40 defects were selected under following criteria: 1. Probing attach loss of at least 6mm, 2. Clinical and radiographic evidence, 3. No furcation involvement
Initial therapy : SRP, OHI. 3 months following completion of initial phase, baseline clinical measurements (plaque, bop, PDs, recession, and probing attach level-PAL) were recorded and a periapical radiograph taken.
Surgery : FTF, degranulated area, SRP w/ hand instruments and ultrasonic, no osseous done, Teflon membrane placed to cover defect for GTR, and intrasurgical clinical measurements and impressions were taken before membrane placement. Flaps were sutured and placed to cover the membrane to the maximum extent.
Membranes removed 4-6 weeks after by doinga partial thickness flap at which time the CEJ and the most coronal extension of the regenerated tissue was recorded. Flaps were sutured and the patients were placed on recall for 1 year.
At 1 year clinical measurements and a periapical radiograph were taken. One week later a re-entry operation was performed in order to evaluate bone healing response in terms of intrasurgical clinical measurements and to obtain an impression of the residual bony defect. Findings on the re-entry procedure will be the subject of a subsequent report. Following healing of the re-entry operation, patients were placed on regular maintenance care.
Results:
PAL gain of 4.1 ± 2.5 mm along with a PD reduction of 5.9 ± 2.5 mm were observed.
PAL gain of 2 mm or more was detected in almost 90% of the treated sites.
No site lost attachment.
Residual PD was 3 mm or shallower in 95% of the sites.
|
Characteristic |
Baseline |
1 year |
|
PAL |
10.9mm |
6.8mm |
|
PPD |
7.9mm |
2.0mm |
|
REC |
2.9mm |
4.7mm |
BL: GTR resulted in a mean gain in PAL of 4.1 mm when treating deep infrabony defects, with 90% of treated sites resulted in a PAL gain of 2 mm or more indicating high reproducibility of the procedures. GTR is a realistic and predictable treatment modality for teeth severely compromised by presence of deep infrabony defects.
P: Evaluate osseous healing response of infrabony defects treated with GTR.
M & M: 23 pts w/ 40 1-, 2-, and 3-wall infrabony defects were treated with membranes (Gore-Tex), no bone graft material was used. PAs were taken with a Rinn, no standardized PAs. The selected sites presented with a vertical bone loss of 12.4 + 2.5mm. The mean total infrabony component was 6.1 + 2.5 mm (CEJ-base of defect). During sx, impressions of the defects were taken at the time of sx and re-entry (this is how measurements were determined such as defect depth, type of defect, result, etc). TTC 250 mg qid for 1 week. Weekly professional cleaning performed for 4 weeks and then monthly for 1 year. Re-entry at 1 year. One root of a 2nd molar scheduled for extraction because of endo perforation (was treated with GTR). It was removed with the surrounding soft tissue (no bone for ethical reasons) and used for histology.
R: Mean 4.3 + 2.5 mm of new bone, along w/ 0.4 + 1.9 mm resorption of alveolar crest. Mean 73 + 31% bone fill. The average fill was 95% for 3-wall, 82% for 2-wall & 39% for 1-wall components. Complete fill was observed in 32.5% of sites & partial fill in 57.5%. Mean x-ray fill was 59 + 37.4%. PI was 13.1% at baseline and was 6.1% at 1 year. Histologically, 4.6 mm of new cementum with inserting fibers. Radiographic measurements underestimated both the original depth of the defect and the extent of bone gain at 1 year.
BL: 73% bone fill w/ the use of GTR with strict plaque control. The average fill was 95% for 3-wall, 82% for 2-wall & 39% for 1-wall components.
Purpose: To identify clinical situations and events which may influence and enhance the extent and predictability of the regeneration in deep intrabony defects following GTR.
Materials and methods: 23 patients with 40 intrabony interpoximal defects, with AL of at least 6mm and radiographic evidence of radiographic component were treated by GTR. During surgery clinical measurements and impressions were taken. Membranes were removed 4-6 weeks after surgery. Distance from CEJ to the most coronal extent of regenerated tissue was recorded. At 1 year clinical measurements and PA radiographs were taken and one week later a re-entry operation was performed. Plaque, BOP, PD, recession (REC) and AL were recorded. Defect angle was recorded radiographically.
Results: The healing period was divided in two parts, before and after membrane removal.
Factors that particularly affect the first phase (tissue formation) were found to be defect morphology, membrane positioning and coverage and infection control.
Defect morphology was the most important with the deeper defects having more tissue gain and the wider the width of the defect angle, the lower the expected regeneration.
At 1 year (2nd phase) tissue gain at membrane removal, defect angle, coverage of newly formed tissue and full mouth BOP at 1 year were highly significant.
The subgroup with insufficient coverage of the newly formed tissue at membrane removal was on average 1.8mm less than the sites where good coverage was achieved.
The higher the tissue gain at membrane removal, the higher the bone fill at 1 year. Width of the defect angle and 1-year full mouth bleeding score had a negative effect on the bone fill. Subgroup with a good coverage at membrane removal had on average 2mm more bone fill.
Conclusion:
The amount of the regenerative tissue under the membrane was dependent upon the baseline depth of the intrabony component when the membrane was positioned just coronal to the bone crest.
Achievement and maintenance of membrane coverage did not seem to play a major role as a determinant of tissue gain.
The amount of regenerated PAL and bone gain at 1 year was dependent upon the amount of tissue gain obtained at membrane removal.
The regenerated tissue obtained at membrane removal should be protected during the maturation phase. Lack of good coverage resulted in a decrease of about 2 mm of regenerated PAL and bone fill.
Infection control (full mouth BOP) significantly affected the maturation process.
Control of the identified predictor variables might improve the extent and predictability of GTR.
Purpose: The purpose was to describe the clinical outcomes following titanium reinforced membranes and modified papilla preservation technique in treating intrabony defects and to compare the efficacy of 3 treatment modalities in the treatment of deep interproximal intrabony defects.
Materials and methods:
45 patients w/ 45 defects were assigned to 1 of 3 groups.
1) Titanium reinforced membranes placed just apical to CEJ w/a modified papilla preservation technique
2) e-PTFE membrane placed at level of alveolar crest
3) flap debridement (MWF for access).
Random assignment to 1 of 3 groups after defects were matched for the depth of infrabony component and PAL.
Membranes removed at 6 weeks. Observed for 1 year where patients had prophy every week for 6 weeks, then monthly for remainder of time (after membrane removal).
Results:
All treatment modalities resulted in clinically & SSD improvements in CAL & PD at 1 year.
SSD amount of CAL gain observed in test group (5.3 mm) with respect to both e-PTFE group (4.1 mm) & flap control group (2.5mm).
The modified papilla preservation and titanium reinforced membrance allowed for a more coronal FGM than at baseline: the 1 year CAL (4.7 mm) was located more coronally than at baseline of interproximal crest (5.9 mm).
BL: Combination of papilla preservation technique w/ self-supporting membranes resulted in greater CAL improvements than conventional GTR or access flaps & the displacement of clinical CAL coronal to interproximal bone crest is possible.
Caton 1994 ARTICLE resorbable barriers
P: To evaluate the clinical effects of GTR therapy of Class II furcations using resorbable periodontal mesh barriers.
M&M: 40 healthy patients with adult periodontitis, each having a Class II facial or lingual furcation were recruited. 20 pts received barrier treatment (experimental) and 20 pts received flap debridement alone (control). The Class II furcation had a depth of 3mm or greater but did not open through to the other side of the tooth. 2-3 mos prior to surgery, the pts received OHI and SRP of all teeth. Surgery at exp sites consisted of FTF, removal of granulation tissue, SRP as needed, and cleaning in the furcation and walls with rotary instruments. Inner surface of flap was curetted to remove the epithelium. The barriers fitted to cover the furcation and 2-3mm of the alveolar bone and secured with sling suture. Flap was placed coronal to the barrier. No dressing was used, abx given for 2 weeks. Post op care included suprag polishing for plaque removal at weekly intervals for 6 weeks. Identical procedures performed at control and experimental sites with the exception of membrane placement. Pre and post-surgical measurements included: GI, PI, BOP, PD, GM, and CAL. The PD and PAL were taken before surgery, at 6 weeks, and at 2, 3, 4, 5 and 6 months after surgery. Teeth included both maxillary and mandibular molars.
R: GI was SS higher in the control group in all time points after 6 weeks. Plaque was SS greater in the control group at 2 and 3 months after surgery. BOP was markedly lower in the exp sites vs the control sites. PD after surgery in the control group was SS deeper (6.2mm) compared to the exp group (4.0mm). Recession was greater at all time points in the control group. SS greater gain of attachment at sites that received the barriers. 15/20 (75%) Class II furcations in the synthetic barrier group and 1/20 (5%) Class II furcations in the control group, were converted to Class I furcations.
D: PD, rec, loss of attachment, and vertical/horizontal depth of the furcations were significantly less in the exp sites. This confirms the notion that conversion of Class II to Class I furcation involvement improves the clinical periodontal status, probably by facilitating OH and prophylactic measures at these sites. It therefore, appears that GTR procedures offer a distinct advantage for the patient as compared to conventional surgical treatment alone.
BL: Resorbable synthetic barriers for GTR therapy in Class II furcations resulted in significant reduction of furcation involvement.
P: To evaluate the result of the GTR using bioresorbable membrane (Guidor).
M&M: 3 study centers, 66 defects in 59 patients (19 Class II mandibular furcations and 47 2-3 wall infrabony defects with minimum PD of 6mm and infrabony component exceeding 3mm on radiographs). SRP and OHI given. At surgery, FTF, degranulation, root debridement and Guidor was placed over all defects with no bony recontouring and flaps were coronally placed. Peridex was used b.i.d. x 6 weeks and penicillin for 5 days. Prophylaxis every 2 weeks for first 3 months and then once every month for following 3 months. The effect of therapy was evaluated by assessing PD, Clinical attachment level (CAL) and the position of the gingival margin prior to and 12 months after the surgery.
R: Exposures in 10/66 (15%) at 1-2 weeks after procedure. Exposure spontaneously disappeared in 6-8 weeks. In no case this was associated with inflammation, pocket formation, infection.
|
Furcation |
Intrabony |
|
|
PD |
6.6 to 2.9 mm (mean 3.7 +/- 1.4 mm) |
8.4 to 3.0 mm (mean 5.4 +/- 2.3 mm) |
|
CAL gain |
3.4 mm vertical 3.3 mm horizontal |
4.9 mm All sites, but 1 gained > 2 mm |
|
Recession |
0.2 mm +/- 1.5 mm |
0.5 mm |
|
9 defects were clinically closed 9 defects converted to Class I 1 defect remained unchanged |
BL: Guidor gave good results in a multi-center study. 1) Reduced PD, 2) gain of clinical probing attachment and 3) Low incidence of gingival pathology, gingival recession and device exposure.
Study supported by Guidor **
One of the authors is scientific director at Guidor research center
Cortellini 1996 ARTICLE comparison studies
Purpose: To compare the results using a resorbable GTR with a nonresorbable GTR and a conventional flap on interproximal intrabony defects.
M&M: 36 defects (PD avg-9 mm, Intrabony defect around 7mm) in 36 patients were divided randomly into 3 groups. Resorb membrane (Test); e-PTFE membrane (Membrane control), and MWF (flap control). Tetracycline QID and CHX for 3-6 wks given post op. Clinical parameters were measured at 1 wk prior to surgery and 1-year post op. Non-resorbable membranes were removed at 6 wks.
Results:
|
CAL gain |
PD change |
Additional Recession |
|
|
Resolut |
4.6 (3-7 mm) |
9.8 to 3.3 mm |
2.0 mm |
|
e-PTFE |
5.2 (3-7 mm) |
8.8 to 2.9 mm |
0.8 mm |
|
MWF |
2.3 (1-3 mm) |
8.5 to 4.2 mm |
2.0 mm |
The difference between both membranes and the MWF group were statistically significant, however there was no statistic significance between the 2 membrane groups. CAL of 4 mm was observed in 83% of GTR sites and none of MWF sites. Less recession in the e-PTFE group, but NSSD. No bony regeneration coronal to the bone crest.
BL: Both Gore Tex and Resolut membranes performed better than MWF regarding CAL gain in interproximal defects and PD. Bioresorbable membranes can be use for deep intrabony defects, it reduces patient morbidity.
P: To compare the healing results in intrabony defects 12 and 30 months after placement of resorbable and non-resorbable membranes.
M&M: split mouth design- 10 patients with 10 pairs of contralateral lesions were treated with either a resorbable (polyglactin-910) or non-resorbable (e-PTFE) membrane. Clinical examinations (BOP, REC, PD, AL) and standardized radiographic examinations were done immediately before as well as 12 and 30 months after surgery. Pts did not brush for 6 wks post-op. Digital subtraction radiography was done for the quantitative assessment of bone density changes.
R: Both types of membranes provided significant attachment gain after 12 months (polyglactin: 81.7%; e-PTFE: 100.0%- NSSD) and after 30 months (polyglactin: 69.1%; e-PTFE: 83.8%- NSSD) compared to baseline. In 90.0% of both, a probing attachment gain of at least 2 mm was maintained over the 30-month period. DSR showed bone density gain in both 12 and 30 months postsurgically- though NSSD b/t the two. NSSD in any of the clinical parameters measured.
BL: Resorbable polyglactin membranoes can be a useful alternative to e-PTFE membranes for GTR.
Evans 1997 No ARTICLE
Background: First Nyman in 1982 reported the results of a clinical case in which principles of GTR were used. Principles of GTR: 1) exclusion of epithelium and connective tissue of flap while allowing PDL fibroblasts and undifferentiated from PDL and adjacent bone to migrate into the defect. It is believed that undifferentiated cells become cementoblasts and osteoblasts resulting in true regeneration of PDL apparatus. 2) a physical space for the ingrowth of these desired tissues
Non-resorbable: ePTFE (expanded popytetrafluoroethylene)
Resorbable: collagen, PLA/PGA (polylactic, polyglactin)
Purpose: To review the literature on barrier regenerative techniques in human intrabony defects and mandibular class II furcations focusing on clinical outcomes.
Materials and methods: Medline and personal search. For intrabony defects only studies that reported values for mean changes in PDs, recession and CAL were included. For the furcation review, only studies in which the frequency of clinical complete or partial furcation closure could be determined were included. Guided tissue barriers included: ePTFE membranes, collagen membranes, PLA/PGA membranes and rubber dam. Many of the studies included OFD as control treatment. Meta-analysis was performed.
Results:
Intrabony defects: 18 studies
Decrease in PDs
PLA/PGA barriers: 5.3mm
Collagen membrane+ bone graft: 3.4mm
OFD: 3.5mm
CAL gain
PLA/PGA: 4.7mm
Collagen membrane or rubber dam: 4mm
Collagen membrane+bone or OFD- 2.3mm
Furcation defects: 13 studies
Decrease in PDs
PLA/PGA barrier: 2.8mm
CPF: 1.3mm
CAL gain
PLA/PGA: 2.3mm
CPF: 0.4mm
Mean vertical CAL gain with PLA/PGA was twice that of collagen (1mm) and 3 times that of ePTFE (0.7mm) and ePTFE +bone graft (0.8mm). Horizontal furcation improvement followed similar patterns. Complete furcation fill was a relatively infrequent result of GTR. Complete closure occurred in 19% of furcations treated with PLA/PGA, 14% with collagen barriers and 7% with ePTFE barriers. No complete furcation closure with OFD or CPF.
Disc:
NSSD in clinical improvement among different GTR barriers in either intrabony or furcation defects. In intrabony defects, no SSD between various GTR barrier techniques and OFD.
In class II furcation defects, no SSD between GTR groups and OFD or CPF. No SSD among GTR techniques for furcation closure.
Great variation among results with GTR. Factors: patient selection, defect selection, technique, post-sx care. Smoking is an important factor. Other variables are membrane exposure, thickness of KG, plaque control, wound stabilization and protection of the clot, professional maintenance.
Conclusion: The use of various GTR barriers yields consistent improvement in clinical status. Considerable variation in results even among studies that the same GTR barrier was used. PLA/PGA barriers had the best results for intrabony and furcation defects. NSSD between different GTR barriers.
Purpose: To assess the efficacy of GTR in treatment of periodontal infra-bony defects measured against conventional surgery (OFD).
Materials and methods:
Systematic review. Inclusion criteria : Randomized, controlled trials (RCTs) of at least 12 months duration comparing guided tissue regeneration (w/ or w/o materials) with OFD for the treatment of periodontal infrabony defects. Furcation involvements and studies specifically treating aggressive periodontitis were excluded. 17 RCTs were included in this review, 16 studies testing GTR alone and 2 testing GTR and bone substitutes.
Results:
No tooth loss was reported in any study although these data are incomplete where patient follow up was not complete.
For attachment level change:
GTR>OFD, with GTR mean difference greater by 1.22 mm
GTR + bone substitutes was 1.25 mm.
GTR showed SS benefit when comparing the numbers of sites failing to gain 2 mm attachment.
Probing depth reduction:
GTR>OFD, 1.21 mm greater reduction for GTR, weighted mean difference 1.24 mm.
Gingival recession:
OFD>GTR, SSD greater recession for OFD than GTR - with a mean difference 0.26 mm- with a greater change in recession from baseline for the control group.
Hard tissue probing at surgical re-entry:
GTR>OFD, SS greater gain was found for GTR compared with OFD- a mean difference of 1.39mm.
GTR + bone substitutes the difference was greater, with mean difference 3.37 mm.
Adverse effects:
Generally minor, an increased treatment time for GTR.
Exposure of the barrier membrane was frequently reported with a lack of evidence of an effect on healing.
BL: GTR has a greater effect than open flap debridement, including improved attachment gain, reduced pocket depth, less increase in gingival recession and more gain in hard tissue probing at re-entry surgery. However there is marked variability between studies and the clinical relevance of these changes is unknown.
Murphy-1 1995 ARTICLE complications
P: 1) To define the most common postoperative complications associated with GTR performed with Gore-Tex Periodontal Material (GTPM) 2) To determine the incidence of these post-op complications. 3) To identify any predisposing characteristics for development of the post-op complications and 4) To suggest methods for prevention and treatment.
M&M: 102 sites (62 patients, 48female/14male), 18-71 years, were included. Sites chosen for tx satisfied the following pre-op criteria: incomplete resolution of the defects after initial therapy which consisted of SRP, modified O’Leary PI > 85%, pre-surgical PD > 6mm, wide osseous and furcation defects not amenable to ostectomy or conventional osseous grafting procedures, occlusal adjustment and splinting if necessary. FTFs were raised, defects were debrided, TTC was applied on the roots for 3 minutes, osseous grafting (DFDBA) +GTPM was used in 36/102 (35%). The decision to graft was empirically based on the need for the graft material to prevent the collapsing of the barrier membrane into the defect. The GTPM was secured to the tooth with Gore-Tex suture. Doxycycline, narcotic analgesic and CHX were prescribed for the time the membrane remained in place. Patients were examined weekly until the barrier was removed. The time of removal was based on the presence of signs of infection or clinical inflammation of the gingival tissues. At the time of removal, probing attachment level measurements were taken.
R: Exposure of membrane in 87% of treated sites. The defects were almost evenly distributed among the maxilla and mandible. Average time to exposure was 2-3 weeks post -op. Most sites were exposed by 2 weeks. In the majority of the sites, the membrane was removed between 6 and 8 weeks. Abnormal post-op pain was the most frequently described complication (16%). Purulence occurred in 1/10 sites (11%), swelling, sloughing and exophytic tissue developed in 1/15 sites.
Pain: Of the sites with abnormal pain, 81% were located in mandibular molar sites. 82% of the sites that presented abnormal pain were class II and III furcations. A strong correlation was found between the presence of pain and the presence of post-op swelling.
Swelling: 7% of all sites displayed residual swelling at 1 week. Methylprednisolone dramatically decreased the incidence of post - op swelling in mandibular molar sites.
Purulence: Evenly distributed between maxilla and mandible. The average time of the onset of the purulence was 6 weeks and occurred only at sites of material exposure. Anterior teeth had greater incidence of purulence. Bacteriologic studies revealed: 46.2% cocci, 49.1% non-motile rods, 1.7% spirochetes, 3% motile rods. 40% of the purulent sites displayed resistance to penicillin. Resistance to TTC and metronidazole was also found.
The occurrence of exophytic tissue and sloughing was rare.
C: Abnormal post-op pain was the most frequently found complication (16%). Swelling was positively associated with the presence of pain. The immediately post-op use of Medrol reduced the incidence of post-op swelling in the mandibular posterior areas. Only the sites with material exposure displayed purulence. Gore-Tex should be removed in 4-6 weeks to prevent purulence. Systemic doxycycline is suggested because it helps post-op healing, but the ideal antibiotic remains to be determined.
Purpose: To examine the effect of post-operative healing complication on periodontal wound regeneration when Gore-Tex Periodontal Material (GTPM) is used in a GTR procedure and to examine the effect of grafting and prolonged GTPM retention on the immediate postoperative regenerative result.
Materials and methods: 62 defects in 36 patients, average age of 53 years. Osseous grafting under the GTPM (DFDBA) was used in 21/62 sites. Pts were seen weekly until the membrane was removed. Defect depts. Were assessed during surgery and at membrane removal. During healing phase presence of five complications (pain, swelling, purulence, sloughing and presence of exophytic tissue) was recorded.
Results: Membrane was exposed in 85% of the cases, with most exposures occurring within 2 weeks. Average time of exposure was 18 days. Membranes were removed between 42-63 days (average 57 days). Most common complication was postoperative pain (15%) and purulence occurred in 13% of the sites. The post-surgical complications had no effect on the AL gain. (Sloughing reduced the AL but NSSD).
Grafting and the time of membrane removal demonstrated a positive effect on the immediate gain in AL. The use of allografts potentiates the gain in vertical AL when the GTPM is left in for a longer period of times (more than 6 weeks) (7.25 vs 3.67mm).
When no grafting was performed the enhancing effect of prolonged retention of the membrane was no seen. The % of gain for the grafted sites was greater for those with initial depth of 7-8mm but lower for defects less than 6mm or more than 9mm.
Conclusion: Healing complications do not demonstrate a significant effect on short term gain in open probing attachment level. A synergistic enhancement is seen when allografts are used and longer retention of the membrane takes place. The removal or the membrane at 4-6 weeks will decrease the incidence of complications but may impair the regenerative process.
Purpose: systematic review to assess the efficacy of guided tissue regeneration procedures in patients with periodontal osseous defects.
Materials and methods
Focused question “ what is the effect of physical barriers compared with surgical controls in clinical, radiographic, adverse and patient centered outcomes?
Electronic search of the Cochrane Oral health group up to January 2002.
From 1543 studies, 89 studies selected for inclusion.
Results
This review failed to identify any studies meeting the inclusion criteria, which evaluated outcomes for more than 5 years.
Reduction of PD and gain in CAL were uniformly enhanced in GTR procedures compared to OFD.
GTR procedures resulted in greater CAL gain when compared to OFD controls regardless of barrier used.
No differences between ePTFE and bioabsorbable barriers when examining PD reduction.
GTR procedures resulted in greater gain in vertical probing attachment compared to OFD.
The use of ePTFE + graft material resulted in significant greater gain compared to ePTFE alone.
There was a negative association between smoking and clinical outcomes.
Conclusions
GTR procedures compared to OFD are more favorable in gain of CAL and PD reduction
In furcations, GTR compared to OFD results is more favorable gains in vertical probing attachment and reduction in vertical probing depths.
NSSD between barriers used.
The use of augmentation materials plus barriers enhances the regenerative outcome in the treatment of furcations.
No advantage to the use of augmentation materials in addition to the barrier in intrabony defects.
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