2. Surgical Principles II. – Second stage: Healing Abutments; Soft tissue One and Two stage approach techniques. Abutment design concepts and scientific rationales


Rapid Search Terms


Book chapters

  • Misch. Stage II Surgery: Uncovery and Treatment of Healing Complications (CH 32). pp 720-738. Contemporary Implant Dentistry, Misch, C.E., 3rd Edition, 2008, Mosby Year Book.
  • Part III Postoperative Complications (complications 33-35). pp 105-107. Surgical complications in oral implantology: etiology, prevention, and management Louie Al-Faraje. Quintessence Pub., c2011.

One stage vs. two stage implants

  1. Boioli LT, Penaud J, Miller N. A meta-analytic, quantitative assessment of osseointegration establishment and evolution of submerged and non-submerged endosseous titanium oral implants. Clin Oral Implants Res. 2001 Dec;12(6):579-88.
  2. Esposito M, Grusovin MG, et al. Interventions for replacing missing teeth: 1- versus 2-stage implant placement. Cochrane Database Syst Rev. 2009 Jul 8;(3):CD006698.
  3. Yoo JH, Choi BH, et al. Influence of premature exposure of implants on early crestal bone loss: an experimental study in dogs. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008 Jun;105(6):702-6

Tissue Characters around implants

  1. Delgado-Ruiz RA, Calvo-Guirado JL, et al. Connective Tissue Characteristics around Healing Abutments of Different Geometries: New Methodological Technique under Circularly Polarized Light. Clin Implant Dent Relat Res. 2013 Oct 10. doi: 10.1111/cid.12161. [Epub ahead of print]
  2. Linkevicius T, Apse P, Grybauskas S, Puisys A. The influence of soft tissue thickness on crestal bone changes around implants: a 1-year prospective controlled clinical trial. Int J Oral Maxillofac Implants. 2009 Jul-Aug;24(4):712-9.
  3. Rungcharassaeng K, Kan JY, et al. Immediate implant placement and provisionalization with and without a connective tissue graft: an analysis of facial gingival tissue thickness. Int J Periodontics Restorative Dent. 2012 Dec;32(6):657-63.
  4. Linkevicius T, Puisys A, et al Crestal Bone Stability around Implants with Horizontally Matching Connection after Soft Tissue Thickening: A Prospective Clinical Trial. Clin Implant Dent Relat Res. 2013 Sep 17. [Epub ahead of print]

Second Stage Surgery (uncovery)

  1. El-Kholey KE. Efficacy and safety of a diode laser in second-stage implant surgery: a comparative study. Int J Oral Maxillofac Surg. 2014 May;43(5):633-8.
  2. Saade J, Sotto-Maior BS, et al. Pouch Roll Technique for Implant Soft Tissue Augmentation of Small Defects: Two Case Reports with 5-Years Follow-up. J Oral Implantol. 2013 Jun 10. [Epub ahead of print]
  3. Tinti, C., Benfenati, S: The ramp mattress suture: A new suturing technique combined with a surgical procedure to obtain papillae between implants in the buccal areas. Int J Perioodontics Restooorative Dent. 2002 Feb; 22(1):63-9
  4. Lee EK, Herr Y, et al. I-shaped incisions for papilla reconstruction in second stage implant surgery. J Periodontal Implant Sci. 2010 Jun;40(3):139-43..
  5. Tal, H: Spontaneous early exposure of submerged implants I Classification and clinical observations. J Periodontol 70: 213-219, 1999
  6. Hertel M et al. Premature exposure of dental implant cover screws. A retrospective evaluation of risk factors and influence on marginal peri-implant bone level changes. Clin Oral Investig. 2017 Jul;21(6):2109-2122.
  7. Basetti RG et al. Soft tissue augmentation procedures at second-stage surgery: a systematic review. Clin Oral Investig. 2017 Sep;20(7):1369-87.
  8. Lin CY, Chen Z, Pan WL, Wang HL. Impact of timing on soft tissue augmentation during implant treatment: A systematic review and meta-analysis. Clin Oral Imp Res 2018;508-521.
  9. Froum et al. Incision Design and Soft Tissue Management to Maintain or Establish an Interproximal Papilla Around Integrated Implants: A Case Series. Int J Perio Rest Dent 2018. Jan/Feb;38(1):60
  10. Urban IA, Klokkevold PR, Takei HH. Papilla Reformation at Single-Tooth Implant Sites Adjacent to Teeth with Severely Compromised Periodontal Support. Int J Periodontics Restorative Dent. 2017 Jan/Feb;37(1):9-17.

Healing Abutments

  1. Bressan E, Tessarolo F, Sbricoli L, et al. Effect of chlorhexidine in preventing plaque biofilm on healing abutment: a crossover controlled study. Implant Dent. 2014 Feb;23(1):64-8.
  2. Koutouzis T, Koutouzis G, Gadalla H, Neiva R. The effect of healing abutment reconnection and disconnection on soft and hard peri-implant tissues: a short-term randomized controlled clinical trial. Int J Oral Maxillofac Implants. 2013 May-Jun;28(3):807-14.
  3. Lin MI, Shen YW, Huang HL, Hsu JT, Fuh LJ. A retrospective study of implant-abutment connections on crestal bone level. J Dent Res. 2013 Dec;92(12 Suppl):202S-7S. Cardoso RC, Gerngross PJ, Dominici JT, Kiat-amnuay S. Survey of currently selected dental implants and restorations by prosthodontists. Int J Oral Maxillofac Implants. 2013 Jul-Aug;28(4):1017-25.
  4. Esposito et al. Do repeated changes of abutments have any influence on the stability of peri-implant tissues? One-year post-loading results from a multicenter randomized controlled trial. Eur J Oral Implantol. 2017;10(1):57-72.

Boioli 2001 one stage vs. two stage implants

D: Two implant placement methods are used in oral implantology: submerged (S, two-stage surgical procedure) and non-submerged (NS, one-stage surgery). However,
a quantitative assessment of their influence on implant osseointegration, summarising the whole present experience, is not directly possible, owing to the lack of normalisation of the published results.

P: to help improve the quantitative assessment of this influence by defining normalization criteria, which would allow the pooling of the results with adequate statistical method.

M: meta-analysis of studies 1980-1999 (published in a peer, reviewed journal, reports on implants placed with a submerged (S) or non submerged (NS) procedure, reports clinical results on implant survival, early failure rates, survival rate. Statistical analysis was competed.

R: 13049 Type S and 5515 type NS implants were initially considered for follow-up with a life table. 16626 Type S and 4716 type NS implants were considered for at the calculation of early failure. Average early failure rate higher for S implants (3.3%), compared to NS implants (1.6%). With confidence level of 95%, expected cumulative survival rate (CSR) should be higher than 92% for S implants after 15 years and for NS implants, than 85% after 10 years or 89% after 8 years.

C: S and NS implants give acceptable results in terms of survival, and for both categories (but especially for S implants) the placement stage remains a noticeable individual cause of failure. S implants have been studied more and presents less dispersed results. NS implants, while osseointegrating better initially, are subject to causes of osseointegration loss, which persist over a longer period of time.

Esposito 2009

P: To evaluate whether a 1-stage implant placement procedure is as effective as a 2-stage procedure.

M: The Cochrane Oral Health Group’s Trials Register, CENTRAL, MEDLINE and EMBASE were searched. Handsearching included several dental journals. Selection criteria :All RCTs of osseointegrated dental implants comparing the same dental implants placed according to 1- versus 2-stage procedures with a minimum follow up of 6 months after loading. Outcome measures were: prosthesis failures, implant failures, marginal bone level changes on intraoral radiographs, patient preference including aesthetics, aesthetics evaluated by dentists, and complications. Data collection and analysis:Data were extracted by two review authors independently using specially designed data extraction forms. Authors were contacted for missing information.

R: Five RCTs were identified and included reporting data on 239 patients in total. On a patient, rather than per implant basis, the meta- analyses showed no statistically significant differences for prosthesis and implant failures, however trends suggested less implant failures with the 2-stage approach especially in fully edentulous patients.

BL: The 1-stage approach might be preferable in partially edentulous patients since it avoids one surgical intervention and shortens treatment times, while a 2-stage approach could be indicated when an implant has not obtained an optimal primary stability, when GTR is needed, or when a removable prostheses could transmit excessive forces on the healing abutments especially in fully edentulous patients.

Cr: The number of patients included in the trials was too small to draw definitive conclusions.

Yoo 2008

Purpose: To compare the effects of both abutment-connected implants and prematurely exposed implants on crestal bone loss.

M&M:6 mongrel dogs had implants placed at edentulated sites on each side. One side had a partially exposed cover screw and on the other side a smooth healing abutment was placed so that the coronal portion of the abutment remained exposed to the oral cavity. Animals were sacrificed 8 weeks after implantation. Bone blocks were taken and examined using micro-CT analysis.

Results:Bone around the implants was more abundant in the abutment-connected sites than partially exposed sites. Average bone height was greater in the abutment-connected sites (9.8 ±0.5 mm) than for the partially exposed fixture (9.3±0.5 mm; P < .05).

Conclusion:Abutment connection can limit crestal bone loss around exposed implants. In cases of early exposure of implants, the placement of a healing abutment may help limit bone loss around implants.

Delgado-Ruiz 2015 abutment geometry

Purpose: To describe contact, thickness, density, and orientation of connective tissue fibers around healing abutments of different geometries by means of a new method using coordinates.

Materials and Methods: Following the bilateral extraction of mandibular premolars (P2, P3, and P4) from six fox hound dogs and a 2-month healing period, 36 titanium implants were inserted, onto which two groups of healing abutments of different geometry were screwed: Group A (concave abutments) and Group B (wider healing abutment). After 3months the animals were sacrificed and samples extracted containing each implant and surrounding soft and hard tissues. Histological analysis was performed without decalcifying the samples by means of circularly polarized light under optical microscope and a system of vertical and horizontal coordinates across all the connective tissue in an area delimited by the implant/ abutment, epithelium, and bone tissue.

Results: In no case had the connective tissue formed a connection to the healing abutment/implant in the internal zone; a space of 3510 μm separated the connective tissue fibers from the healing abutment surface. The total thickness of connective tissue in the horizontal direction was significantly greater in the medial zone in Group B than in Group A (p < .05). The orientation of the fibers varied according to the coordinate area so that internal coordinates showed a higher percentage of parallel fibers in Group A (p < .05) and a higher percentage of oblique fibers in Group B (p < .05); medial coordinates showed more oblique fibers (p < .05); and the area of external coordinates showed the highest percentage of perpendicular fibers (p < .05). The fiber density was higher in the basal and medial areas (p < .05).

Conclusions: Abutment geometry influences the orientation of collagen fibers; therefore, an abutment with a profile wider than the implant platform favors oblique and perpendicular orientation of collagen fibers and greater connective tissue thickness.

Linkevicius 2009


The aim of this clinical trial was to evaluate the influence of gingival tissue thickness on crestal bone loss around dental implants after a 1-year follow-up.


Forty-six implants (23 test and 23 control) were placed in 19 patients. The test implants were placed 2 mm supracrestal, whereas the control implants were positioned at the bone level. Before implant placement, the tissue thickness at implant sites was measured with a periodontal probe. After healing, metal-ceramic cement-retained prostheses were constructed. According to tissue thickness, the test implants were divided into A (thin) and B (thick) groups. Intraoral radiographs were performed and crestal bone changes were measured at implant placement and after 1 year.


Mean bone loss around the test implants in group A (thin mucosa) was 1.61 +/- 0.24 mm (SE; range, 0.9 to 3.3 mm) on the mesial and 1.28 +/- 0.167 mm (range, 0.8 to 2.1 mm) on the distal. Mean bone loss in test group B (thick mucosa) implants was 0.26 +/- 0.08 mm (range, 0.2 to 0.9 mm) on the mesial aspect and 0.09 +/- 0.05 mm (range, 0.2 to 0.6 mm) on the distal aspect. Mean bone loss around control implants was 1.8 +/- 0.164 mm (range, 0.6 to 4.0 mm) and 1.87 +/- 0.166 mm (range, 0.0 to 4.1 mm) on the mesial and distal aspects, respectively. Analysis of variance revealed a significant difference in terms of bone loss between test A (thin) and B (thick) groups on both the mesial and the distal.


Initial gingival tissue thickness at the crest may be considered as a significant influence on marginal bone stability around implants. If the tissue thickness is 2.0 mm or less, crestal bone loss up to 1.45 mm may occur, despite a supracrestal position of the implant-abutment interface.

Rungcharassaeng 2012
Background:Facial gingival tissue thickness (FGTT) is important for an esthetically pleasing anterior restoration since it determines the soft tissue’s ability to conceal the underlying restorative material.

Purpose:The purpose of this study was to investigate the change in FGTT after immediate implant placementand provisionalization with and without a connective tissue graft.

Material and Methods:Patients with a failing maxillary anterior tooth planned for immediate implant placement and provisionalizationwith (CT group) or without (NCT group) a subepithelial connective tissue graft were included in this study. After tooth extraction, direct measurement of the FGTT was performed; subsequent measurements were performed at the time of definitive prosthesisplacement. Data were analyzed using independent and paired t tests at a significance level of α = .05.

Results:There was no statistically significant difference in the mean FGTT at tooth extraction between the CT and NCT groups. At prosthesis delivery, the mean FGTT for the CT group was significantly greater than that of the NCT group. The mean FGTT of both groups at prosthesis delivery was significantly higher than that at tooth extraction. The mean change in FGTT in the CT group was also significantly greater than that in the NCT group.

Conclusion:Immediate implant placementand provisionalization (IIPP) in conjunction with a connective tissue graft is more likely to result in sufficient peri-implant tissue thickness to conceal underlying implant restorative materials than when performed without a connective tissue graft. The tissue thickness is maintainable and is stable 6 months after IIPP.

Linkevicius 2013

P:The purpose of this study was to evaluate how implants maintain crestal bone level after soft tissue thickening with allogenic membrane in patients with thin soft tissue.

M&M:103 partially edentulous patients were selected. A midcrestal incision in the center of edentulous ridge was performed, leaving at least 2 mm of keratinized gingiva bucally. Facial flap was reflected then the mucosal thickness of the lingual flap was measured. Based on thickness patients were divided into 3 groups;

  • A:<2 mm thickness- implants placed in thin soft tissues (n=34)
  • B:<2 mm thickness – implants placed in thin soft tissues and thickened with allogenic membrane at the time of implant placement (n=35)
  • C:>2 mm thickness – implants placed in naturally thick tissue (n=34)

One-stage surgery was used for groups A & C, and two-stage surgery for group B. All groups had received antibiotic prophylaxis but for B group post-operative antibiotic was also prescribed. Implants with horizontally matching connections and laser modified surfaces were placed. For groups A & C healing abutments were connected immediately after implant placemen and tissue was sutured around them.

Forgroup B, after 2 months of healing, second stage surgery was performed, and tissue thickness was measured again. Healing abutments were placed and tissue sutured.

2 month later, prosthesis (screw-retained) were placed. Radiographic examination was performed: after implant placement, 2 months after healing, after restoration, and at 1-year follow-up. Crestal bone loss was measured mesially and distally.

R:Overall, the implant survival rate after 1 year of function in all groups was 100%.crestal bone resorption at 1-year follow-up was:

  • Group A: 1.65 ± 0.08-mm mesially – 1.81 ± 0.06 mm distally
  • Group B: 0.31 ± 0.05 mm mesially – 0.34 ± 0.05 mm distally (tissue thickness had increased to 3.83 ± 0.13 mm)
  • Group C: 0.44 ± 0.06 mm mesially – 0.47 ± 0.07 mm distally

Differences between A and B, and A and C were significant both mesially and distally, whereas differences between B and C were not significant mesially or distally. Implants in naturally thick and augmented soft tissues experienced minor bone remodeling, and implants in thin tissues experienced more bone loss.)

C:Results show a reduction of crestal bone loss from 1.81 mm to 0.44 mm when tissue was thickened with allogenic membrane. This outcome can be due to providing the site with adequate thickness for biologic width and therefore adequate peri-implant seal.

BL:thin mucosal tissues may cause early crestal bone loss, butthickening the tissue with allogenic membrane may significantly reduce bone resorption.

Critique:long-term evaluation? Different surgical placement approaches. (one-stage vs. two-stage)

El-Kholey 2014

P:To assess if dental implant uncovering is possible with a diode laser without anesthesia, and to compare its performance with traditional cold scalpel surgery.

M&M:30 healthy pts (19W, 11M, ages 25-54yrs). 45 implants are placed with 2-stage technique (43 traditional flap, 2 flapless). After 12 weeks, patients returned for second-stage surgery. Patients were divided into two groups. Control Group: 15pts, 22 implants exposed through circular incision using a No. 15 surgical blade. Patients were asked to return after 1 week for clinical evaluation. Experimental group: 15pts, 23 implants exposed using a 970nm diode laser. For comparison of the two techniques, the following parameters were assessed: 1) Need for local anesthetic and amount; 2) Duration of surgery; 3) Intraoperative bleeding; 4) Subjective pain scale; 5) Patients asked to record their use of analgesic medication during the postoperative pain; 6) Time for taking final impression

R:Significant difference between the 2 groups regarding the need for local anesthetic. All control patients needed local anesthetic, and only 1 experimental patient needed local. No bleeding was encountered during the laser surgery, while normal bleeding occurred during traditional surgery. The duration of surgery was comparable for both methods. Postoperatively, no patient in either group suffered from significant pain, with no significant difference between the two groups. After 7 days, the laser-treated group was completely healed with no signs of inflammation or edema. In the control group, healing was adequate at 7 days, but there was some edema present at the gingival margins. The mean time to taking of impressions for the laser-treated patients was 7.13 days, while it was 12.0 days for the control group; however, this was not found to be statistically significant.

D: Application of the surgical lasers for uncovering implants offers a series of potential advantages: improved vision due to hemostasis, less mechanical trauma, elimination of need for local anesthetic, shortening time needed to take final impression. Punch incisions were not used in this study, but this could potentially improve healing process. The only limitations to the use of the laser to uncover implants are the lack of adequate zones of keratinized tissue and knowledge of where the implant has been placed. There is concern over damaging the implant with use of a laser, but studies have shown that the diode is one of the safest types of lasers to use around implants.

BL: The use of a diode laser in second stage implant surgery can minimize surgical trauma, eliminate the need for anesthesia, improve visibility during surgery due to absence of bleeding, and eliminate postoperative discomfort.

Saade 2013

PURPOSE: To describe the pouch roll technique for implant soft tissue augmentation of small defects to achieve contemporary patient aesthetic expectations and preserve periodontal health longitudinally (5 years). Procedure was performed during placement of a nonsubmerged implant or during second stage surgery.

METHODS:Technique description: Intrasulcular buccal incision made, which continued interproximally along the teeth to the palate, followed by horizontal incision. A semilunar incision was then made, maintaining the delicate 1 to 2 mm of gingival sulcus, which will become the interproximal papillae. Minipedicle flap was de-epithelialized. Full thickness flap then elevated, creating a pouch the length of the minipedicle flap. The minipedicle is sutured beneath the full thickness flap on the buccal surface of the implant.

RESULTS/DISCUSSION/CONCLUSION: This study demonstrated that over 5 years of follow up, the pouch roll technique maintained its stability and is a less invasive option for restoring marginal gingival contour. It is recommended that this technique be performed concomitant to implant surgery so that second stage surgery may be used as an additional opportunity to modify soft tissues if necessary.

5 year follow up photographs of both cases:

BL: Pouch roll technique offers many advantages for restoring small soft tissue defects associated with implants. Advantages: preservation of papilla, increased soft tissue thickness, aesthetic improvements, healing by primary intention, less invasive, cost effective. Disadvantages: Cannot restore more than 2-3 mmsoft tissue defects (bone grafting required for these defects).

Tinti 2002
to show the opportunity and predictability of creating new papillae between implants in the buccal aspect by dislodging a thick palatal flap buccaly and sutured using the ramp mattress suture.
M&M:8 patients aged between 37 and 63 years whom received Branemark implants in the anterior and lateral sextants of the maxilla by a two-stage surgery has consented to participate in this study. A Sharp linear incision in a distomesial direction is performed with a full thickness approach slightly palatal to the implants, starting 5 mm posterior to the most distal implant and ending 5 mm mesial to the most mesial implant. The placed healing abutments will keep the full-thickness buccal flap raised during the healing period and the vestibular gingival margin will be coronal to the palatal gingival margin by 5 to 6 mm. The ramp mattress suture is made by passing the needle through the vestibular site of the buccal flap in the interproximal area in a vestibulopalatal direction approximately 5 mm apical to the gingival margin. On the palatal site, the palatal flap has been engaged from its entire thickness and approximately 5 mm apical to the gingival margin by passing it in a palatovestibular direction; then it is immediately repassed in a vestibulopalatal direction, approximately 5 mm distal. At this point, the buccal flap has to be engaged in a palatovestibular direction 5 mm apical to its gingival margin, and the knot is placed on the vestibular site approximately 3 mm distal to the first entry point. Second surgical phase, after an adequate healing period of approximately 4 to 5 weeks, a vestibular scalloped gingivectomy is performed around the vestibular surface of the abutment to create either a scalloped gingival margin or interproximal papillae only in the vestibular area and a crown lengthening procedure is performed on the adjacent teeth.

Results:After a 12-months healing period, the gingiva appeared healthy and not inflamed. Probing depthswere 1 mm palatally, 2 mm buccaly and 3 mm interproximally without bleeding. The newly formed papillae were cleansable, stable without shrinkage. Radiographically, the bone crests remained flat and unchanged. However, improved esthetics have been maintained throughout the 12 months follow up period.
Conclusion:The authors confirm the capability of forming interproximal papillae using the ramp mattress suture in conjunction with delayed gingivectomy based on 56 treated papillae. The clinical results were stable, shrinkage was no more than 30% of the buccaly displayed flap, and the esthetics results were satisfying to the clinician and patient.

Lee 2010

Purpose:Pink gingival esthetics, especially on anterior teeth has been a critical factor in deciding the overall success of the implant-supported restoration. Soft tissue profile is one of the most important factors, and most specifically, inter-implant papillae are a critical factor for implant esthetics. Reconstructing a predictable implant papilla is the most complex aspect of implant dentistry. Various techniques for inter-implant papilla reconstruction, at the time of second surgery stage, have been introduced. The aim of this study is to suggest and evaluate a surgical technique for reconstructing inter-implant papillae.

M&M: A 28-year-old male had an implant placed on the 13 (6) and 14 (5) area. After a healing period of four months after implant placement, a second stage surgery was planned for inter-implant papilla reconstruction, using the method of an I-shaped incision, method modification of the suggested technique by Shahidi et al: A labial horizontal incision was performed mesiodistally 0.5 mm-1mm inside from the labial border of the implant. A horizontal incision was also performed parallel to the buccal side, on the palatal side, which was in contact with the palatal borderline of the implant different from the labial side. Another incision was done bucolingually over implant midline perpendicular to horizontal incision lines performed on labial and palatal sides. The flap was reflected and implant was exposed to connect the healing abutment and both flaps were folded up along the healing abutment, without a suture.

Results: Two weeks after surgery, soft tissue augmentation between the two implants was achieved.

Conclusion:I-shaped incisions for papilla reconstruction performed during the second stage implant surgery were useful for inter-implant papilla reconstruction and showed a good esthetic result. The advantage of this method is a decrease in chair time, less postoperative discomfort and great esthetics.

Topic: Second Stage (Uncovery)

Author: Tal H.

Title: Spontaneous early exposure of submerged implants: I. Classification and clinical observations.

Source: J Periodontol. 1999 Feb;70(2):213-9.

Type: clinical

Keywords: Dental implants/classification; infection; prevention and control; osseointegration.

BACKGROUND: Spontaneous early exposure of an implant is one of the complications that canadversely affect osseointegration of implants.

METHODS: This study clinically classified spontaneous early exposure, described and analyzed this complication in a group of 148 patients treated with 372 submerged implants: 216 (58%) in the mandible and 156 (42%) in the maxilla. Edentulous sites were exposed by mid-crestal incisions and full thickness gingival flaps. Incisions were closed in an attempt to achieve complete closure and healing by primary intention. Measurements were taken to avoid mechanical trauma to the mucosa over the implants. Patients were followed up weekly and examined to identify early exposures. Perforations were classified according to the degree of exposure from 0 (no perforations) to 4 (complete exposure).

Class 0: The mucosa covering the implant is intact

Class 1: a breach in the mucosa covering the implant is observed. Oral implant communication can be detected with a periodontal probe but the implant surface cannot be observed without mechanically interfering with the mucosa

Class 2: The mucosa above the cover screw is fenestrated; the cover screw is visible. The borders of the perforation’s aperture do not reach or overlap the borders of the cover screw at any point

Class 3: Cover screw is visible. In some parts, the borders of the perforation aperture overlap the borders of the cover screw.

Class 4: Cover screw is completely exposed

RESULTS: Of the implants 51 (13.7%) presented spontaneous early exposure, (13%) in the mandible and 23 (14.7%) in the maxilla. Class 2 perforation was the most frequent, followed by Class 3, Class 1 and Class 4. Inflammation at the mucosal orifices of the perforations was minimal, but no objective index (bleeding, probing) was taken in order to avoid morphological changes of the lesions that were biopsied for histological examination.

CONCLUSIONS: Early perforation and partial exposure of the implant’s covering device are a nidus for plaque accumulation. If left untreated, this may result in inflammation and damage to the peri-implant mucosa, and possible peri-implant bone.

The possible reasons of early perforationinclude, failure of the mucosal incision to produce healing by primary intention due to tension in the flaps, acute mechanical trauma or continuous pressure over the implant’s covering and cover screw loosening.


Topic: Uncovery

Author: Moritz Hertel & Yun-Chie Roh & Konrad Neumann & Frank Peter Strietzel

Title: Premature exposure of dental implant cover screws.
A retrospective evaluation of risk factors and influence on marginal peri-implant bone level changes

Source: Clin Oral Invest (2017) 21:2109–2122

Type: clinical.

Keywords: Dental implant . Cover screw . Premature exposure . Marginal peri-implant bone level change

Purpose: The purpose of this study were to identify risk factors associated with the premature cover screw exposure (pCSE) at dental implants and to evaluate the influence of a pCSE on peri-implant marginal bone level (MBL) change compared to non-exposed implants.

Methods: Retrospective data collected and studied from 165 patients (mean age = 54.0 ± 14.4 years) who received 395 submerged implants. Demographic, health-related, and therapeutic variables were analyzed for their respective impact. MBL change was detected bydigital radiographs obtained from first- and second-stage surgeries.

Results: pCSE were detected in 43 patients (26.1%) and 53 implants (13.4%). An increased frequency of exposure was significantly associated with (I) male gender (p = 0.012) at patient level and (II) the posterior region of the jaws (p = 0.005), implant systems with platform-matching cover screws, and a vertical distance of ≥0.5 mm between bone crest and the implant platform (both p < 0.001) at implant level. The decrease in mesial, distal, and total MBL differed significantly (mean total = 0.8 ± 0.7 vs. 0.3 ± 0.5 mean mesial = 0.8 ± 0.8 vs.0.3±0.6 mean distal=0.8±0.8vs.0.3±0.6mm p < 0.001) between non-exposed and pCSE implants.

Discussion/Conclusion: Radiographically detectable peri-implant bone level change is one of the relevant criteria for peri implant health as well as for the successful evaluation of implant-prosthetic rehabilitation. This study showed that pre- mature exposures of cover screws were found to be more commonly associated with male gender at the patient level and with the posterior region of the alveolar ridges of the maxilla and the mandible. The radiographically detectable loss of marginal bone height was significantly higher around implants with prematurely exposed cover screws compared to those with non-exposed cover screws.



Topic: Second-stage surgery soft tissue augmentation procedures

Author: Bassetti R, Sculean A.

Title: Soft tissue augmentation procedures at second-stage surgery: A systematic review.

Source: Clin Oral Investig. 2017 Sep;20(7):1369-87.

DOI: 10.1007/s00784-016-1815-2

Type: Systematic review

Keywords: Second-stage surgery . Re-entry . Peri-implant keratinized mucosa . Peri-implant soft tissue volume

Purpose: To evaluate the efficacy of different soft tissue augmentation/correction methods in terms of increasing the peri-implant width of keratinized mucosa (KM) and/or gain of soft tissue volume during second-stage surgery.

Methods: Electronic search perfomed in MEDLINE and EMBASE to identify relevant literature up to July 31, 2015. The search string comprised the combination of key words and free-text terms, the linkage was conducted using Boolean operators. Aditionally a manual search of relevant articles since 1900 was performed.

Inclusion criteria: Publication in peer-reviewed literature, case series, prospective cohort study, controlled clinical trial, randomized clinical trial, full text in English or German, Studies in which an insufficient soft tissue condition around submucossaly osseointegrated dental implants existed at the time of second-stage surgery, all implant were placed submucosally, observation period of at least 3 months.


10 out of 1627 fulfilled the inclusion criteria applied in this systematic review. In all 10 publications evaluated, the estimated risk of bias was considered high.

Width of keratinized tissue: Depending on the surgical technique applied and graft material used, the enlargement of KT ranged between -0.20 and 9.35mm. Two studies compared the application of Xenogenic Collagen Matrices (gain after 3 months 9.35mm, 6 months 7.13mm, 60 months 5.53mm) to that of Free Gingival Graft (Gain after 3 months 8.93mm, 6 months 8.13mm, 60 months 7.70mm). In both groups, a statistically significant increase in KT was achieved.

Another study compared the application of an apically positioned partial-thickness flap (gain 4.63mm). In a prospective clinical study, a combination of APFTF and PCPCTG was applied at second stage-surgery. At 3-5 months, a mean final gain of KT of 3.07mm was reported. Compared with baseline, in one study applying APPTF technique, a final loss of 0.20mm was reported.

Postoperative shrinkage or relapse of KM

In the first study, a shrinkage rate after a follow-up of 6 months of 32.92% for the control group (APPTF + FGG) and 41.12% for the test group (APPTF + XCM) after 60 months such one of 40.65% for the control group and 52.89% for the test group was documented, respectively. The highest reduction in KT width after surgery occurred in early healing phase and up to 6 months.


Soft tissue thickness: Only one of the 7 studies reported on the change in soft tissue thickness between baseline and 12 months after intervention. In group 1 (APPTF), a mean soft tissue thickness gain of 1.37mm was measured. Furthermore, measurements of 2.41 mm in group 2 (Roll Envelope Flap) and 3.10mm in group 3 (APPTF + SCTG) were reported. The differences between groups were statistically significant.

Augmentation of peri-implant soft tissue volume during second-stage surgery: 62 patients and 90 implant sited were treated using a soft tissue augmentation technique. index system where the soft tissue convexity at the facial implant aspect (CPF) was assessed before surgery (CPF 0.58), 1 week after surgery (CRF 2.58), and 6 months after surgery (CRF 1.83). A statistically significant increase in volume was reported at both follow-up time points.

Discussion/Conclusion: Studies demonstrated that both an adequate peri-implant width of KM and an adequate soft tissue thickness seem to have an impact on the long-term stability of peri-implant tissues.

1) Compared to implant sites with a band of ≥ 2mm of KM, sites with less than 2mm seem to be more prone to brushing discomfort, plaque accumulation, and peri-implant inflammation.

2) Thin peri-implant mucosal tissue is associated with more crestal bone loss.


Topic: Second stage (uncovery)

Author: Lin et Al.

Title: Impact of timing on soft tissue augmentation during implant treatment: A systematic review and meta-analysis

Source: Clinical Oral implants research

DOI: 10.111/clr.13148

Type: Systematic review and meta-analysis.

Keywords: Dental implants, keratinized tissue, mucosal recession, soft tissue augmentation, soft tissue thickness, systemic review and meta-analysis.

Purpose: examine the effect of timing on soft tissue augmentation outcome during implant treatment and assess the soft tissue conditions as well as its stability overtime.

Methods: Based on Population, Intervention, Comparison, and Outcome (PICO) criteria, the question for the present literature search was addressed as follows:

P: patients received dental implant placement in partial edentulous sites,

I: autogenous soft tissue graft (either free gingiva graft or connective tissue graft) was performed to improve the peri-implant soft tissue conditions,

C: perform soft tissue grafting at different time points during implant treatment, either simultaneously or after implant surgery (staged), and

O: improve the keratinized tissue width (KTW), STT and minimize mid-buccal mucosal recession.

Eligible studies were included if they met the following criteria: (1) any human studies (prospective or retrospective, randomized or not, cohort or case series trials); (2) dental implants should be located in single or partial edentulous areas; (3) soft tissue augmentation/ correction should be performed during or after implant placement; (4) at least 3-month follow-up period after soft tissue augmentation; (5) autogenous soft tissue graft used for soft tissue augmentation/correction; (6) data of KTW and/or STT and/ or MR available; and (7) full text in English.

Electronic and manual searches for articles written in English up to September 2017 were performed by two independent reviewers. Human clinical studies with the purpose of evaluating outcomes (at least 3-month follow-up) of autogenous soft tissue graft for augmentation during implant treatment, either simultaneous or after implant placement (staged), were included. Cumulative changes of keratinized tissue width (KTW), soft tissue thickness (STT), and mid-buccal mucosal recession (MR) data were analyzed with a random effects model to compare the postoperative outcomes.


  • Width of Keratinized tissue gain: Majority of the studies are in favor of having a band of KT to not only improve esthetic appearance but also to facilitate oral hygiene performance for better implant long-term stability. Among all related articles, apically positioned flap plus vestibuloplasty and autogenous grafts was regarded as the most effective technique to obtain KT. In spite of less surgical time and patients comfort autograft remains the gold standard for soft tissue augmentation in terms of KTW, tissue thickness, esthetic and long-term volume stability.
  • Soft tissue thickness: Soft tissue volume comprises two parts in different directions: biological width and soft tissue thickness. To facilitate evaluation the effect of timing on soft tissue augmentation outcomes, we subdivided the assessment into two groups (simultaneous or staged). Data from this review showed 0.95 and 1.12 mm of STT gain in staged and simultaneous groups, respectively. However, no significant difference was found. Soft tissue graft during implant treatment could definitely be considered to improve the contour and esthetics, especially in thin biotype. Interestingly, the soft tissue stability on simultaneous soft tissue graft remains a concern among many clinicians, however, both groups achieved comparable STT gain.

Data from this paper showed techniques used for harvesting autogenous soft tissue did not affect the outcomes.

Conclusion: The limitations of this review should be acknowledged. (1) Most of the included studies had small sample sizes and short follow-up periods; (2) there were inconsistencies in methodologies with various treatment modalities; (3) the present review includes only English language publications, which may have introduced selection bias. Therefore, there is a need for a better RCT with longer follow- up, larger sample size, and clearer study design that compares simultaneous and staged soft tissue augmentation.


Topic: Second stage (Uncovery)

Author: Froum, S

Title: Incision Design and Soft Tissue Management to Maintain or Establish an Interproximal Papilla Around Integrated Implants: A Case Series

Source: Int J Perio Rest Dent 2018. Jan/Feb;38(1):60-

Introduction: One of the challenges in creating an esthetic and successful implant restoration is maintenance or reconstruction of the interproximal papillae. The papillae height between an implant and a natural tooth is reported to average 4.5 mm and 3.5 mm between 2 implants.

3 essential factors for maintaining or regenerating soft tissue quality and volume around implants are preservation of blood supply, minimal scar tissue formation during surgery and preservation of the bone.

Objective: The objective of this article is too present a retrospective series of 14 consecutive cases of 22 implants in the esthetic zone, where specific incision designs and soft tissue management techniques were used at the time of implant placement and the second stage abutment or provisional restoration surgery.

Methods: A total of 14 patients were included in the study, 8 of which received 10 nonadjacent implants while 6 received 2 adjacent implants. The implants sites included central, lateral and premolar. Horizontal ridge augmentation was preformed whenever the buccal plate was less than 2 mm thick, (which was the case in 21 out of 22 patients). Implants were placed with a thermoplastic surgical guide. All implants had cover screws and were submerged when horizontal ridge augmentation was done. 90days later, second stage abutment insertion surgery was performed. A U shaped incision with divergent arms open toward the palate was reflected, a platform switching abutment was connected. A provisional restoration was also delivered on the same appointment. Clinical and radiographic examination were performed by 2 independent calibrated clinicians to evaluate the presence of papillae at each postsurgical visit.

Results: excellent results shown on clinical photos in article.

Discussion: This study shows that papillae can be predictably maintained or regenerated when using specific incision designs at the time of the implant placement. Careful planning and meticulous execution to maintain healthy soft tissue should be performed throughout all procedures.

Conclusion: The critical factors for success were: 1- the preservation of the blood supply, 2- preservation of bone on the teeth adjacent to the implant, and 3- minimal scar tissue formation.


Topic: Second stage uncover.

Author: Urban,I., Klokkevold, P., Takei, H

Title: Papilla reformation at single tooth implant sites adjacent to teeth with severely compromised periodontal support.

Source: The international Journal of Periodontics and Restorative Dentistry 2017 Jan/Feb;37(1):9-1

DOI: 10.11607/prd.2818.

Type: Clinical case

Keywords: papilla reformation, interdental papilla, periodontal support, single tooth implant.

Purpose: to determine factor that will influence in the formation of interdental papilla.


Case 1: Healthy 45-year-old woman with a compromised maxillary left central incisor that was treated endodontically (due to a trauma two months ago), pocket probing depth of 9 mm with bleeding, high mobility, and severe loss of interradicular bone.

Extraction of the tooth with autogenous bone graft, collagen membrane, and connective tissue graft. After six months of healing, the implant (Nobel Biocare) was placed with a full-thickness flap, and a prefabricate surgical guide. After the implant placement a 2 mm dehiscence appeared in buccal. Due to that, autogenous bone and a subepithelial connective tissue graft were placed to treat the dehiscence and augment the interproximal bone. After 6 months, the area healed and a provisional restoration, which stayed in mouth for 6 months, was placed 2 weeks after the implant exposure. Finally, a zirconia abutment and crown were delivered. After 9 year both the implant and interdental papilla were successful.

Case 2: Healthy 25-year-old women presented for an evaluation after implant, and bone graft failure on the maxillary left central incisor. The implant placement and the bone graft were placed simultaneously. A decision was made to remove the implant, reconstruct the hard and soft tissue architecture for esthetics, and place a new implant. Bone graft was removed with curettes, 8 weeks later, the process was repeated. A full thickness midcrestal incision was made on the alveolar crest. Autogenous bone from ascending ramus and inorganic bovine bone were used. An implant and a polytetrafluoroethylene membrane were placed. After 9 months, the membrane was removed, and a standard diameter implant was placed (Nobel Biocare). After 6 months, the area healed and a provisional restoration, which stayed in the mouth for six months, was placed 2 weeks after the implant exposure. Finally, a zirconia abutment and crown were delivered. After 7 year both the implant and interdental papilla were successful.

Discussion/result: The cases presented examples of successful implant placement and reconstruction of interproximal bone and papilla if the time to heal is enough. Even though no histologic slides were presented, clinical stability and the excellent esthetics demonstrate the successful of this treatment. There is a biologic limit to created papilla that is 5 mm from interdental bone to contact point.

Conclusions: Connective tissue and bone graft should be done simultaneously. These cases were challenging and required multiple surgeries and extended healing times. Patient preparation and careful selection is strongly recommended. More research and clinical trials should be done to have more information before they are recommended into routine clinical practice.

Bressan 2014

P: The study aimed at evaluating the effect of chlorhexidine (CHX) in preventing plaque biofilm (PB) formation on healing abutments (Has) in patients rehabilitated with osseointegrated implants

M&M:54 Has were placed 1 week after implant surgery (test group). After 7 days, a new set of 50 Has were placed in the same implant sites and removed 1 week after (control group). During the 2 testing periods, patients were instructed to apply: CHS mouth rinsing twice daily and no brushing (test); no CHX mouth rinsing and no brushing (control). Scanning electron microscopy and image analysis were blindly used to objectively quantify plaque biofilm amount on removed HAs.

R: Median values and interquartile ranges of the percent ratio of titanium surfaced covered from PB were 0.9 (test) and 1.2 (control).

C: CHX mouth rinse significantly limited plaque formation on HAs, being a valid contribution to mechanical brushing in early phases of plaque control on dental implants.

Koutouzis 2013

P: to evaluate the effect of healing abutment disconnection and reconnection on soft and hard peri-implant tissues.

M&M:The study is a prospective randomized controlled clinical trial. 16 patients were included. An endodontic file was used to measure soft tissue thickness. Following one-stage implant placement, test group implants (n = 10) received a permanent abutment and control group implants (n = 11) received a healing abutment. After 2 months of healing, control group implants underwent a prosthetic protocol involving implant-level impressions and a two-time abutment disconnection and reconnection process prior to delivery of the definitive prosthesis. Test group implants underwent a prosthetic protocol involving abutment-level impressions without any abutment disconnection. Clinical parameters (PI, PD, BOP, KG, peri-implant mucosa height PMH) were recorded at 2 weeks, 2 (before impression taking), 3 (immediately after pros delivery), and 6 months after surgery. Marginal bone levels were assessed radiographically at implant placement at 3 and 6 months.

R:The overall survival rate from implant placement to the last follow-up visit was 100% for both groups. The mean marginal bone loss at the 6-month examination was 0.13 mm for test group implants and 0.28 mm for control group implants. There were no significant differences regarding changes in peri-implant mucosal dimensions between the two groups.

Marginal bone level changes (mean and standard variation-mm)
time Test
At 3 month -0.07 (0.13)
At 6 month -0.13 (0.20)

C:The study indicates that implants receiving a final abutment at the time of implant placement exhibited minimal marginal bone loss and were similar to implants subjected to abutment disconnection and reconnection two times.

BL: Disconnection and reconnection of the abutment two times did not cause negative dimensional changes in the peri-implant mucosa.

Lin 2013

P:The aim of this retrospective study was to determine if peri-implant crestal bone level alterations at different time phases may depend on the type of implant abutment connection.

M&M:Only single implants or two implants splinted with a fixed prosthesis were used in this study. Diameters used (4 to 5mm) and length of implants used (10 to 12mm). Implants were embedded at crestal bone levels and cover screws to facilitate healing were placed (for 3 to 6 months). After connection of impression copings, a PA was taken, which served as the baseline for crestal bone level. The time intervals for radiographs: T0 (day of implant delivery); T1 (day of prosthesis delivery); T2 (3 months after loading); T3 (6 months after loading). All PA radiographs were taken with a cone indicator with a standardizing radiographing process. The following measurements were collected: Bone-implant contact (BIC) and vertical bone gap (VBG). Differences in the VBG measured at various time were used to quantify the changes in the peri-implant bone level. SPSS 18 was used for statistical analyses. Three-implant abutment connection types were analyzed (external hex, internal octagon, and internal Morse taper).

R:The results indicated that there were no SSD among the different types of implant-abutment connections

D:The mean changes of the peri-implant crestal bone were less than 1mm in the first year for all implants. One limitations of this study was the small sample size, which was due to the strict inclusion criteria. Further studies, with longer follow up times, are needed.

BL:The level of peri-implant crestal bone does not differ significantly during either the healing phase or the loading phases among 3 different implant-abutment connection designs. The level of peri-implant crestal bone changes significantly with the time interval (healing phase, loading phase 1, and loading phase 2), with it being slightly greater before the application of occlusal loading.

Topic: Abutment changes on periodontal stability

Author: Esposito M, Bressan E, Luongo G.

Title: Do repeated changes of abutments have any influence on the stability of peri-implant tissues? One-year post-loading results from a multicentre randomised controlled trial

Source: Eur J Oral Implantol. 2017;10(1):57-72.

DOI: PMID: 28327695

Type: Multicentre RCT

Keywords: dental implant, immediate loading, peri-implant marginal bone levels, repeated abutment changes

Purpose: To compare hard and soft tissue changes between immediately non-occlusal loaded implants which had definitive abutments placed at implant placement and never removed versus conventionally loaded implants which had provisional abutments changed at least three times.


2 Groups: 1) patients having implants which received abutments that were removed at least three times and were conventionally loaded after 3 months of unloaded healing and 2) Patients who received definitive abutments immediately after implant placement and were immediately loaded, without removing the abutments.

Inclusion: any partially edentulous patient requiring one fixed implant supported prosthesis supported by a maximum of three implants, 18 years or older. One prosthesis per patient was considered with an initial insertion torque of at least 35Ncm.

-20 Patients (per practice) were recruited and treated in four Italian private practices and categorized into 1) non-smokers, 2)moderate smokers and 3) heavy smokers.

After the implant placement, PA xrays were taken, amount of keratinized mucosa was measured at the buccal sites.

Implants of the repeated abutment disconnection group, the abutment was removed three times.

1) impression, 2) testing the fit of the metal core or framework, 3) during delivery.

Outcome measures:

-Buccal peri-implant tissue recessions were assessed by a blinded outcome assessor on plaster models taken at delivery of the definitive prosthesis and 1 year after.

-Esthetic evaluation from clinical pictures at 4 and 12 months after loading using the pink esthetic score.

-Patient satisfaction was assessed at 0 and 12 months after loading.

-Peri-implant marginal bone level changes on PA radiographs at implant placement, 4 months after loading, delivery of prosthesis and 1 year after.


A total of 80 patients with 128 implants supporting 41 single crowns and 39 fixed partial prosthesis were included.

-There was no statistically significant differences in failures/complications between the two groups.

-Pink Esthetic Score: after 4 and 12 months, the difference in PES score was not statistically significant between groups. When evaluating the single esthetic domains, in only one case was a statistically significant difference observed. The soft tissue contour at 1 year post-loading with implant of the definitive abutment group scoring 0.25 significantly better than implants of the abutment disconnection group.

-Buccal recession: At 1 year, 0.35mm for definitive abutment group and 0.65mm for the repeated abutment changes group. No statistically significant differences between them.

-Patient satisfaction: all patient declared themselves very satisfied with the outcome.

-Marginal bone level changes: At implant placement there was a statistically significant difference (though not clinically relevant) between the two groups of 0.08mm, in fact bone levels were 0.11mm for the repeated abutment and 0.03mm for the definitive abutment group. At 1 year the difference was statistically significant, 0.06mm for definitive abutment and 0.23mm for the repeated abutment changes group.

-Keratinized mucosa: There was no differences at 4 and 12 months after loading between the two groups.


Apart from 0.16mm of bone loss and 0.25 difference in soft tissue contour of the PES score at 1 year post-loading favoring implant that received definitive abutments which were no longer removed, no other significant differences were observed. Given that no clinically significant differences were observed, clinicians can choose the procedure they find more convenient. Another finding from this trial was that immediate loading procedures did not affect the implant success negatively, which is in agreement with the finding of a Cochrane systematic review.