Discussion Topics
Soft Tissue
What are the components of gingival tissue? How are these components formed embryologically?
How are epithelium and connective tissue related? What are the major fiber types of the gingival connective tissue? The PDL fibers?
Hassell, T.M: Tissues and cells of the periodontium. Periodontal 2000; 3:9-38, 1993.
What are the different types of epithelium found in the oral cavity? What features are unique to each?
Bartold PM, Walsh LJ, Narayanan AS: Molecular and cell biology of the gingival Periodontal 2000 24:28-55, 2000.
Lozdan JC, Squier C. The histology of the mucogingival junction. J. Periodontal Res. 4:83-93, 1969
Stanford TW, Levin MP, Payne TF: A comparison of the mucogingival junction in dentulous and edentulous areas. J. Periodontal. 47:522-524, 1976
What is an interdental papilla? Describe its morphology. Are there different types of papillas?
What determines if epithelium is keratinized or not? How can this influence surgery design?
Karring T, Ostergaard E, Loe H: Conservation of tissue specificity after heterotopic transplantation of gingival and alveolar mucosa. J. Periodontal Res. 6:282-293, 1971.
Karring T. Lang N, Loe H: The role of gingival connective tissue in determining epithelial differentiation. J. Periodontal Res. 10:1-11, 1975.
What is the importance of gingival pigmentation? How can this influence surgery design?
Perlumutter S, Tal H.: Repigmentation of the gingiva following surgical injury. J. Periodontal 57:48-50, 1986
Describe the blood supply to the gingiva. Are there any surgical considerations related to the blood supply?
What causes stippling at the histologic level? Is the presence or absence of stippling important?
Greene AH: A study of the characteristics of stippling and its relation to gingival health. J. Periodontal. 33:176-182, 1962
What is the significance of gingival color?
Baumgartner WJ, et al. The diagnostic value of redness in gingivitis. J Periodontal 37:294-298, 1962
Is keratinized or attached gingiva necessary for health? If so, how much? Does the width of attached tissue change over time?
Bowers GM: Study of the width of attached gingiva. J. Periodontol. 34:201-209, 1963.
Lang NP, Loe H: The relationship between the width of keratinized gingiva and gingival health. J. Periodontol. 43: 623-627, 1972
Schoo WH, van der Velden U : Marginal soft tissue recessions without attached gingiva: A five year longitudinal study. J. Periodontal Res. 20:209-211,1985.
Wennstrom JL: Lack of association between width of attached gingiva and development of soft tissue recession. A 5-year longitudinal study. J. Clin. Periodontol. 14:181-184, 1987.
Tenenbaum H, Tenenbaum M: A clinical study of the width of the attached gingiva in the deciduous, transitional and permanent dentitions. J. Clin. Periodontol. 13:270-275, 1986.
Does the thickness of keratinized tissue influence the surgical treatment plan?
Eger, T., Muller, H.P., Heinecke A.: Ultrasonic determination of gingival thickness. J. Clin Periodontol 23: 839 – 845, 1996
Studer, S., Allen, E.,, Rees., T., Kouba., A.: The thickness of masticatory mucosa in the human hard palate and tuberosity as potential donor sites for ridge augmentation procedures. J. Periodontol 68(2):145-151, 1997
Is keratinized tissue necessary for implants? Why or why not?
Berglundh T, Abrahamsson I, Welander M, Lang NP, Lindhe J.Morphogenesis of the peri-implant mucosa: an experimental study in dogs. Clin Oral Implants Res. 2007 Feb;18(1):1-8.
Adibrad M, Shahabuei M, Sahabi M. Significance of the width of keratinized mucosa on the health status of the supporting tissue around implants supporting overdentures. J Oral Implantol. 2009;35(5):232-7.
Bouri A Jr, Bissada N, Al-Zahrani MS, Faddoul F, Nouneh I. Width of keratinized gingiva and the health status of the supporting tissues around dental implants. Int J Oral Maxillofac Implants. 2008 Mar-Apr;23(2):323-6.
Marquez IC. The role of keratinized tissue and attached gingiva in maintaining periodontal/peri-implant health. Gen Dent. 2004 Jan-Feb;52(1):74-8; quiz 79. Review.
Guglielmoni P, Promsudthi A, Tatakis DN, Trombelli L.Intra- and inter-examiner reproducibility in keratinized tissue width assessment with 3 methods for mucogingival junction determination. J Periodontol. 2001
Discussion Topics: Soft Tissue
What are the components of gingival tissue? How are these components formed embryologically?
Review article about the development of the periodontium
· Periodontium is defined as the tissues supporting and investing the tooth. The tissues supporting are developmentally derived from the dental follicle proper, whereas those investing the tooth are an adaptation of the oral mucosa.
· Regulatory genes and signaling molecules participate in cell differentiation. Neuroectoderm -> Ectomesenchyme -> Dental follicle -> Periodontium.
· The cells detach from the neuroectoderm of the neural crest and migrate and differentiate to form a variety of different tissues including mesenchyme or embryonic connective tissue. This mesenchyme is designated as ectomesenchyme to reflect its origin from the neuroectoderm.
· Odontogenesis: the initiation of tooth development has long been a matter of debate with experiemental evidence presented to support either a lead role for the epithelium of 1st arch or the ectomesenchyme of the 1st arch. It seems like it is more complex situation and than odontogenic potential is present in epithelium and ectomesenchyme. There is a transfer of patterning and signaling mechanisms from the epithelium to the ectomesenchyme. Local upregulation involves both the ectomesenchyme which forms the dental papilla and the ectomesenchyme that forms the dental follicle.
· Dental follicle: is the formative organ for the tissues of tooth support. Tissue between the tooth germ and the forming bone of the jaw
· All the evidence to this point indicates that the tissues of tooth support (cementum, periodontal ligament and alveolar bone) represent a functional unit, the dental follicle proper, defined developmentally as odontogenic tissue, and a product of the cascade of signaling initiated initially in the first arch epithelium and responded to by the ectomesenchyme of the same arch surrounding the early tooth germ. It is both logical and consistent to reserve the term dental follicle proper for this layer immediately encapsulating the tooth germ as it is clearly odontogenic. Thus, the enamel organ is the formative organ of enamel, the dental papilla the formative organ of the dentine pulp complex and the dental follicle proper, the formative organ for the tissues of tooth support.
- The combination of newer investigative techniques of recombinant DNA technology and immunocytochemistry have established that the dental papilla and dental follicle proper are derived from embryonic connective tissue derived from neuroectoderm (the neural crest). It has also been shown that a cascade of signals exists involving homeobox genes and growth factors initiate odontogenesis and the differentiation of dental tissues. These tissues include acellular cementum, periodontal ligament and alveolar bone proper.
Purpose: To review and depict the protective architecture of the human gingival tissue
Discussion: Clinical and histological features: Externally the gingival extends from the gingival margin to the MGJ. Internally it includes the supra-alveolar fiber apparatus and particular groups of supra-alveolar fibers (could be considered part of the PDL). Therefore it’s regarded as a combination of epithelial and connective tissue that forms a collar of masticatory mucosa around teeth.
MGJ is usually 3-5 mm apical to the level of the alveolar crest and it remains constant with increasing age.
Gingival height increases from the primary to the permanent dentition.
Gingival thickness ranges between .5 and 2.5 and is inversely proportional to gingival height.
Strictly normal gingival is an artifact that can be produced under rare experimental conditioned where there is no need for a defense mechanism.
Clinical normal gingiva exists under a low-grade defense in which microbial and antigenic challenges are compatible with health. These defense mechanisms include a gingival sulcus and junctional epithelium (high turn-over rate) with widened intercellular spaces that harbor elevated numbers of neutrophilic granulocytes and sulcus fluid (exudative nature).
The protective function of the gingival epithelium against infection is enhanced by the action of salivary secretions that physically cleanse and lubricate the epithelial surfaces and provide antimicrobial protection through various constituents that are directly toxic to bacteria or interfere with their ability to colonize the mucosal surfaces.
On average, the gingival unit is composed of 4% junctional epithelium, 27% oral gingival epithelium, 69% connective tissue with cellular infiltrate occupying 3-6% of the gingival volume.
The first line of defense is provided by neutrophil granulocytes. The second line of peripheral defense is formed by combined antibody and neutrophil axis, while the last and third defense is provided by monocyte and lymphocyte axis that modulates the inflammatory response.
How are epithelium and connective tissue related? What are the major fiber types of the gingival connective tissue? The PDL fibers?
P: Review the basic structural configuration of the periodontium.
Gingival epithelium consists of 4 layers: strata basale, spinosum, granulosum, and corneum
Basal- cuboidal cells, anchored to basal lamina via hemidesmosomes and adjacent cells w/ gap jxns and hemidesmosomes
Sulcular epithelium- boundries are height of FGM and JE
Junctional epithelium – extends from base of gingival sulcus to an area at the cervix of the tooth near the CEJ, widest (20-30 cell layers) at its most coronal aspect, and tapers to only a few cells near the CEJ
Cells you will find in the epithelial tissue – keratinocytes, melanocytes, langerhans cells
Connective Tissue – 60-65% is collagen
5 principal fiber groups
Dentogingival – connect cementum to lamina propria, provide gingival support
Alveologingival – connect alveolar crest to lamina propria, attach gingiva to bone
Dentoperiosteal – from cementum near CEJ to periosteum of alv crest, anchor tooth to bone
Circular – within attached gingival, encircle each tooth – maintain contour and free margin of gingival
Transseptal – from interproximal cementum coronal to alv crest – maintain relationships of adjacent teeth
Cells in the connective tissue – all blood cells, fibroblasts (65%)
PDL – 0.15-0.4 mm space
5 principal fiber groups
Alveolar crest – from cementum near CEJ apical into alv crest – retain tooth in socket, oppose lateral forces
Horizontal – from coronal cementum laterally into alveolus – restrain lateral movement
Oblique – from cementum of mid root (80-85%) coronally and obliquely into bone – resist axial forces
Apical – from apical cementum apically into bone – prevent tipping, resist luxation
Interradicular – from furcation area cementum apical to bone – aid in resisting tipping and torquing
Ample blood supply
Dental A (pulp), interradicular (bi/trifurcation areas) and Interdental.
Alveolar bone- thickness of the plates varies from tooth to tooth throughout the arch. Typically thickest in the lingual mandible- except in the incisor region. The crest normally follows the CEJ contour and is 2-3mm apical in health. Trabecular bone is found between the cortical plates and serves to buttress the forces applied to alveolar bone- its orientation specific to the direction of forces applied.
Cementum – 50-200 um – principal function is to provide anchorage of tooth into alveolus – accomplished via collagen fiber bundles of pdl (sharpey’s) embedding into cementum. Also serves to maintain interocclusal relationship. As occlusal surface dimension is lost due to attrition, the tooth erupts and more cementum is laid own apically to maintain width of PDL space.
Acellular cementum – more coronal
Cellular cementum – more apical
What are the different types of epithelium found in the oral cavity? What features are unique to each?
Purpose: To discuss the general architecure, cellular composition, bichemical attributes and interactive relationship between the gingivsal epithelium and connective tissue.
Discussion: Periodontium is comprised of four principal components: the gingiva, the PDL, the alveolar bone and cementum. Pathological changes occurring in one component may affect maintenance, repair or regeneration of the other components. Anatomically the gingiva is classified in the free gingival margin, the interdental gingiva and the attached gingiva. Histologically in the overlying epithelial structures (predominantly cellular in nature) and underlying connective tissue (CT) (less cellular, composed primarily of an integrated network of proteins, growth factors, minerals, lipids and water.
Oral gingival epithelium
· Stratified squamous keratinized
· Four layers: stratum basale (basal layer), stratum spinosum (prickle cell layer), stratum granulosum (granular layer) and stratum corneum (cornified layer)
· 0.2-0.3mm in thickness
· Extensions and depression in the CT form the rete ridges
· Basal layer contains keratinocytes, Langerhans cells (associated with protective immunity), melanocytes and Merkel cells (most likely involved in mechano-perception)
Oral sulcular epithelium
· Epithelial lining of the gingival sulcus
· Approximately 0.5mm in depth in health
· Structure and composition is similar to the oral gingival epithelium
· Multilayered and often parakeratinized
· Less infiltrated by PMNs and less permeable comparing to JE
Junctional epithelium
· Extends from the base of the gingival sulcus to approximately 2mm coronal to the alveolar bone crest.
· Formed during phases of tooth eruption
· Nonkeratinized, originates from the enamel organ
· Forms the tissue attachments of the gingiva to the tooth structures
· Ranges in thickness from a few cells at its most apical portions to 15-30 cells at its most coronal portion and cells are parallel to the tooth surface
· Two layers: stratum basale (cells proliferate rapidly) and suprabasale
· No rete ridges
· Larger gaps between cells than oral gingival or sulcular epithelium
· Numerous migrating PMNs that increase in presence of plaque and are associated with gingival inflammation
Epithelia have very little extracellular and in contrast to the CT do not contain any fibrous proteins in the extracellular matrix. Type VIII collagen has been noted and may help the attachment to the tooth. Intercellular material of gingival epithelium contains a variety of glycoproteins, lipids, water and proteoglycans. Intercellular matrix of gingival epithelia serves roles in cell adhesion, adhesion to the tooth surface and basement membrane and also plays an important role the regulation of diffusion of water, nutrients and toxic materials through the epithelium.
Epithelial repair and regeneration
Within hours of injury the epithelial cells begin to migrate to cover the exposed CT. Undamaged cells commence migration under stimuli provided by locally released factors such as epidermal GF, PDGF, fibronectin and other cytokines. In the initial phases of healing (1-2 days) of GV wounds the migrating epithelial surface is 2-3 cells thick and forms a stratum basale. By Day 5 the wound appears fully covered and by Day 7 the epithelium is matured and a new stratum corneum is evident. After gingival flaps epithelium will proliferate apically as long as there are no attached collagen fibers on the root surface, and this process explains the formation of long junctional epithelium. New CT tissue and cementum are formed in the apical part which means that if these tissues are given appropriate time and environment regeneration will occur.
Interface between epithelium and CT
Interface between basal epithelial cells and CT is called basement lamina. It serves as a barried to the exchange of cells and some large molecules across the junction. It is composed of 4 elements: hemidesmosomes, lamina lucida, lamina densa and affine band of specialized CT containing a variety of fibrillar and nonfibrillar proteins. The reticular layer is of CT origin and the other three of epithelial origin.
Basement membrane consists of type IV collagen (major component), laminin and heparin sulfate proteoglycan perlecan, hemidesmosomes, K-laminin, anchoring fibrils which contain type VII collagen and several others proteoglycans. Type VII collagen is the predominant component of the anchoring fibrils of the basement membrane.
JE is associated with two basement membranes. The internal basement lamina facing the tooth and the external facing the CT. Internal basement lamina is unique because it lacks Type IV collagen and prototypic laminin (laminin-1) two common components of basement membranes.
Fibroblast of the gingiva
Gingival CT is a largely fibrous connective tissue. Fibroblast are of mesenchymal origin and play a major role in the development, maintenance and repair of gingival conectivce tissues.
· In vivo they have a typical elongated or spindle shape and, consistent with their high level of synthetic activity, have prominent rough ensoplasmic reticulum and Golgi apparatus
· In vitro these cells may often vary in their appearances
· Wide range of variable features
· Involved in regulatory processes via phagocytosis and secretion of collagenases
· Synthetize MMPs that together with their inhibitors allow for a very regualted control of matrix degradation for remodelling or turnover purposes
· Fibroblasts are very sensitive to changes in the surrounding matrix, GF or cytokines
· They have an ability for site directed migration (chemotaxis) and attachment to various substrata
· Major mediator tha influences the synthesis of collagen and other matrix components of fibroblasts is TGF-β
Matrix composition:
Type I collagen is the main one in all layers of gingival CT. Fibers are arragned in two patterns. One consisting of large, dense bundles of thick fibers (Type I collagen) and the oter a loose pattern of short thin fibers mixed with a fine reticular network (Type III collagen). Gingival CT also contain Type V and VI collagen.
Vascular supply of the gingiva forms to distinct networks, one bounded by the oral and sulcular ginigval epithelia and the other subjacent to the junctional epithelium. Adjacent to the JE the vascular plexus is composed of anastomosing postcapillary venules termed the gingival plexus. Elsewhere in the gingiva the capillary loops consist of an asxending arterial and a descending venous component.
Within the gingival CT most nerve fibers are myelinated and closely associated with the blodd vessels. Nerves may also penetrate in the JE.
Repair of gingival CT
Due to their high turnover rate the CT of the gingivae have remarkably good helaing and regenerative capacity and generally show little evidence of scarring following surgical wounding.
Changes to the gingival tissues with the onset of inflammation
Epithelium and in particular the JE is involved at the earliest phases of the inflammatory response. Many cellular signaling events occur as a rapid response to the accumulation of dental plaque. Epithelial cells can produce numerous cytokines including IL-1 and IL-8, and growth factors such as PDGF-AA and –AB. They express intercellular adhesion molecule-1 and E- selectin. Tissue destruction at the epithelium – CT interface may be associated with changes in interactions between these two tissues and could be mediated via a number of integrins. Because of the JE permeability from the external surface towards the CT a chemotactic gradient is created and more neutrophils are attracted. Once this level of infiltration has ocured and if the driving stimulus remains, the normal rapid turnover of the JE is insufficient to restore health and the pathway to ongoing tissue damaged is established. Ginigval epithelial cells are stimulated to produce collagenase – 3 (MMP-13) byt TNF-α, TGF-β and keratinocyte growth factor. CT destructios occurs 3-4 days after plaque accumulation. The dstruction begins at the perivascular collagen bundles and approximately 70% of collagen within the foci of inflammation is lost. The major inflammtory cells responsible for the destruction are PMNs and macrophages. The inflammatory process develops, tissue destructions expands deeper towards the PDL and alveolar bone. Ginigval fibrosis is seen in slowly progressive periodontitis. TGF-β affects matrix accumulation through activating the transcription of genes of type I, III, IV, VI, and VII collagens and proteoglycans. Collagen synthesis is inhibited by PG-E2, INF-γ and TNF-α.
P: To study the histology of the mucogingival junction (MGJ) of humans and monkeys in order to establish reliable criteria with which to define the MGJ.
M+M: 12 tissue samples of gingiva/mucosa with accompanied MGJ were obtained from M+F pts, 19-59 yrs old and 7 specimens from monkeys, tissue 1-2mm wide.
· Specimens were examined by histological and histochemical (looking at distribution of acid phosphatase and nonspecific esterase- related to process of keratinization) as to examine the keratinization process
R:
· Clinically the MGJ appears as a scalloped line, histologically this line may be represented by a surface groove.
· The mucogingival surface groove (the line between the keratinization and non-keratin) is present in about half of the specimens.
· CT pattern differs on either side of the surface-groove, the MGJ is the point where a sudden increase of elastic fibers occurs as you move towards the alveolar mucosa.
· MGJ can show a slight overlap of keratinization of the type described as incomplete parakeratosis. The most superficial cells resemble the deep cells of the epithelium and are not keratinized.
· Also, there is a change in the distribution of acid phosphatase, esterase, and glycogen, and a transition from keratinized to non-keratinized tissue.
· The changes at the MGJ are due to underlying connective tissue (corium), not from lateral influences.
BL: The mucogingival surface groove (the line between the keratinization and non-keratin) is present in about half of the specimens. The MGJ is the point where a sudden increase of elastic fibers occurs as you move towards the alveolar mucosa. Also, there is a change in the distribution of acid phosphatase, esterase, and glycogen, and a transition from keratinized to non-keratinized tissue. The changes at the MGJ are due to underlying connective tissue (corium), not from lateral influences.
P: To compare the histology and histochemistry of the MGJ in dentulous and edentulous areas.
M&M: 30 specimens (15 dentulous/15 edent) were excised from 10 subjects with an average age of 58. The biopsies were obtained postmortem (within 18 hours of death). All tissues were taken posterior to the first PM and were evenly divided between maxilla and mandible. All edentulous areas had worn RDPs or complete dentures. The specimens were studied for degree of keratinization, occurrence of PAS positive material (glycogen is PAS positive but is rendered nonstaining by diastase digestion), location of elastic fiber termination, epithelial thickness (by means of a calibrated micrometer eyepiece).
R:
Degree of keratinization: orthokeratosis more often in edent attached gingiva (AG), but difference not SS. Transition from parakeratosis or orthokeratosis to nonkeratinized epithelium was noted in the intermediate zone (the distance from the most apical rete ridge characteristic of AG to the most coronal rete ridge charact. of alveolar mucosa) of all specimens. The alveolar mucosa was non-kerat in all but 2 cases.
Occurrence of PAS positive material: glycogen was observed in the more superficial cells of the alveolar mucosa and intermediate zone in all specimens and was uniformly distributed. The difference was not SS.
Elastic fiber termination: elastic fibers either ended in the intermediate zone of AG (not far into it) in all but one edentulous specimen, where they remained entirely in mucosa.
Width of intermediate zone: varied form 600-1800 microns. No SS noted.
Epithelial measurements: AG had longer rete ridge length than mucosa. This difference was not SS
BL: No SS between both areas.
What is an interdental papilla? Describe its morphology. Are there different types of papillas?
P: The purpose of this study was to determine: (1) whether the dental crest is concave or convex in shape, (2) what type of epithelium covers the interdental crest and (3) whether an interdental papilla will regenerate to its original form after excision.
M&M: 16 dental students from Ohio State University, age 22-27. Clinically normal papillae were used between “normally contacting teeth”. Part One: (1) 2 biopsy specimens taken from each student, one from the anterior and one from the posterior region. From maxilla, 6 anterior and 5 posterior were taken. From the mandible, 10 anterior and 11 posterior were taken. Incisions were made along the base of the papilla to the alveolar crest on the facial and lingual. (2) the shape of the interdental crest was determined using a dissecting microscope 12.5x and 50x magnification. (3) papilla photographed in facial/lingual plane. (4) specimens prepared for histologic sectioning. Part Two- the regenerated interdental papilla was excised 32-86 days later from all but one student.
R: part one: 30 of the 32 interdental crests were concave, 15 had a saw tooth appearance. Stratified squamous epithelium covered both lingual and facial peaks and it was non-keratinized in 23 specimens. Epithelial cells of 21 of 32 specimens had a vacuolated appearance. B/L sections had collagenous fiber bundles running through the lamina propria in a B/L direction. Lymphocytes and plasma cells were noted in the connective tissue of 26 specimens, especially adjacent to the epithelial attachment. Part two: 22 papillae did not regenerate to their original height leaving a 0.5-2 mm space. The facial and lingual surfaces of all papillae did not fill the embrasure as seen before excision. 7 specimens were torn during removal and it was not possible to judge their shape. 10 of 23 regenerated papillae were convex. 5 appeared as two marginal margins. Round cell infiltration was noted again but in 8 cases less than the original interdental papillae.
C: As noted prior by Cohen, the interdental papilla is concave (col). The concavity of the 30 interdental crests varied from obvious to slight. They varied from a col shape to a facial peaked concavity. The vacuolated appearance of the epithelial cells of the 21 crestal areas may be caused by increased glycogen content of the cells, which results from slight degree of inflammation. Bundles were seen running in a B/L direction through the lamina propria, which in previous studies was suggested that these fibers assist and maintain the shape and position of the papilla. Round cell infiltration (chronic inflammation) was found in every interdental papilla examined, indicating a defense mechanism responding to the constant presence of bacteria. All regenerated papilla appeared flatter and did not fill the embrasure.
BL: The interdental papilla is concave in shape, is covered with stratified squamous epithelium, mostly non-keratinized, and does not regenerate to its original form and height after excision.
Purpose: To elaborate on the histology of the retrocuspid papillae and propose a hypothesis of origin.
Materials and methods: a) The histopathology files studied by light microscopy of six diagnosed cases as retrocuspid papilla.
b) Ten clinical cases (not biopsied) checked for color change after applying light pressure with the periodontal probe.
c) Previews studies reviewed to determine morphology of blood vessels in the mandibular cuspid area during eruption.
Results:
Histologic findings generally showed alterations of the epithelium (acanthosis and long rete pegs). Epithelium measured from the top of the dermal pegs could be thinner or similar to the surrounding epithelium. Blood vessels number could be increases (three cases), unaltered (two cases) or decreased (one case) compared to the edges of the biopsy.
All cases showed that the retrocuspid papilla blanched after light pressure with the periodontal probe.
Review of studies showed that the encircling plexus of an erupted tooth often anastomoses with the lingual circulation.
Discussion: Differences in vascularity and epithelial thickness explain variations in appearance.
Hypothesis of formation: When the unerupted deciduous cuspid moves coronally, its encircling plexus causes erosion of the lingual cortical plate. Anastomosis of the dento-vascular plexus with the blood supply of the lingual soft tissue, results in the formation of the papilla. During permanent cuspid’s eruption a similar process occurs. The old encircling plexus is now the vascular plexus of the periodontal ligament and is anastomosed to the gingiva at the site of the retrocuspid papilla. Formation of the retrocuspid papilla only occurs in mandibular cuspids. Initially the papilla begins as a slight surface elevation and becomes more prominent in children; however the papillae regress with age. The absence of the papillae could be due to a thick lingual bone, which prevents anastomosis of the plexi. It’s absence can also be caused when the permanent toothbud migrates far enough labially to prevent anastomosis.
Blanching could be used as a tool for differential diagnosis.
What determines if epithelium is keratinized or not? How can this influence surgery design?
Purpose: To study the maintenance of tissue characteristics of gingival, alveolar and palatal mucosa after heterotopic transplantation
Material and methods
8 adult monkeys
Buccal crevicular epithelium adjacent to maxillary and mandibular premolar area was excised
A mucoperiosteal flap consisting of gingiva and alveolar mucosa was elevated
Separate pedicules of gingiva and alveolar mucosa were produced, transported and sutured
In animals free palatal grafts including epithelium and lamina propia were transplanted to the anterior maxilla/mandibular alveolar mucosa.
Recipient sites were prepared by removal of a split thickness flap leaving periostium and a layer of connective tissue adjacent to alveolar bone.
Total material: 20 gingival grafts, 20 alveolar grafts, 14 palatal grafts
Animals were sacrificed, observation periods 5 and 14 days, 1-8, 10 and 12 months
Controls were obtained from tissue adjacent to the donor and recipient sites
Results
60 days post op the appearance of grafts was identical to the tissue of the donor site, in palatal grafts even rugae was present.
The distribution of collagenous, elastic and silver stained fibers, the absence and presence of a keratin layer and localization of a PAS positive material on the epithelium were maintained
Discussion
Tissue characteristics of gingival, alveolar and palatal mucosa are preserved after transplantation to new environment. Grafts displayed clinical features characteristic to the donor site
Histodifferentiation occurs as a response to morphogenic stimuli from connective tissue
Keratinization is not dependent on whether or not connective tissue is attached to hard tissues and not influenced by function.
Conclusions
Major connective tissue characteristics of gingival, alveolar and palatal mucosa are preserved after heterotopic transplant
Specificity is genetically determined and histodifferentiation may be induced by stimuli generated by underlying connective tissue
Grafting of keratinized oral mucosa may be better method for predetermining the post surgical width of the gingiva
P: To study the role of gingival CT in determining the differentiation of the overlying epithelium.
M: Free grafts of CT without epithelium were transplanted from either the keratinized gingiva or the non-keratinized alveolar mucosa (controls) into areas of the alveolar mucosa in 7 monkeys. The grafts were placed in pouches created in the CT as close as possible to the overlying epithelium. After 3-4 weeks, the transplants were exposed by removal of the overlying tissue in order to allow epithelialization from the surrounding non-keratinized alveolar mucosa. The transplants were examined clinically and histologically at 1, 2, 3, 4, 6, 8, 11 and 12 months.
R: The gingival CT grafts became covered with keratinized epithelium displaying the same characteristics as those of normal gingival epithelium. The alveolar mucosa transplants were covered non-keratinized epithelium. Tissue type is determined by CT, not by function.
BL: Gingival connective tissue is capable of inducing the formation of a keratinized gingival epithelium.
What is the importance of gingival pigmentation? How can this influence surgery design?
P: To report 2 cases of ging repigmentation following removal of gingival tissue.
M+M: 2 Jewish Yemanite male patients with moderate or heavy pigmented gingiva received depigmentation via excision of pigmented keratinized gingiva in maxillary anterior for cosmetic purposes. After surgery, the exposed lamina propia was covered with a periodontal pack.
R: 1st pt : 25 years old- area remained depigmented 2 years; at 32 months some pigmentation was observed in previously depigmented areas ąappearing as small spots, pt was advised against further tx and after 7 years with exception of the two limited sites that remained clinically depigmented, the surgical area was repigmented to different degrees.
2nd pt (36 years old)- no repigmentation after 8 years post-op.
D: Possible explanation for the 2 year delay in repigmented areas is that migration of melanocytes did not occur during this period, or that the melanocytes which had migrated were not active. Why migration and/or activation of cells occurs in some patients soon after clinical healing while in other patients the process is delayed is difficult to explain.
BL: Repigmentation post-operatively is spontaneous and unpredictable. Possible explanation of repigmentationą Migration theory where active melanocytes from normal skin and hair proliferate and migrate into depigmented areas.
Describe the blood supply to the gingiva. Are there any surgical considerations related to the blood supply?
P: to report on the vasculature distribution of mongrel dog periosteum
Materials & Methods: 7 mongrel dogs with a healthy peridontium were used. Corrosion casts (injection with acrylic resin followed by dissolution of soft tissue) were prepared of 5 dogs and examined wby SEM. 2 Specimens were injected with India ink and examined by light microscopy.
Results: The plexus of the periosteum in the gingiva is more coarse when compared to the alveolar mucosa which is more dense. In the mucosa, the subepithelial capillaries formed a network structure- there was no papilla formation.
Vessels penetrating the gingiva from the alveolar mucosa run along the bone surface to the alveolar crest. Before reaching the crest, they branch in 2 directions – one runs towards the epithelium buccal and sulcular(plexus of lamina propria), and the other continues along the bone surface (periosteum plexus). The plexus of the lamina propria comprise arterioles and venules (20-40 um), that communicate with vessels in the alveolar bone through the Volkman’s canals. Beneath the buccal gingival epithelium, short conical papilla were seen in the connective tissue. The capillary structure resembled a loop, and the appearance replicated the papilla. At the MCG, the vasculature transformed from a loop to a netlike structure. Beneath the sulcular epithelium, the connective tissue displayed a smooth concavity with no papilla. Capillaries formed a smooth concavity from the free gingival margin to the edge of the junctional epithelium.
Bottom Line: There is a correlation between the morphological consistency of the connective tissue and its microvasculature architecture.
P: To determine if increased blood flow associated with gingivitis would decrease following resolution of gingival inflammation, if increased blood flow in inflamed gingiva was associated with changes in the blood flow of the alveolar bone, and if blood flow in gingiva and alveolar bone increased if periodontitis was reactivated by ligating teeth.
M&M: adult beagle dogs with naturally occurring periodontitis were included. 1st experiment: left maxillary and mandibular teeth of 4 dogs were left untreated whereas the right maxillary and mandibular teeth received SC/RP on the beginning of the experiment, brushed daily and scaled weekly to maintain gingival health. Clinical parameters were taken weekly and blood flow was measured after 12wk. 2nd experiment: all teeth of 5 dogs received SC/RP on day 0. Floss- covered wire ligatures were placed in cervical grooves of mandibular right teeth and retained for 12wk. Left mandibular teeth were brushed daily and scaled weekly to maintain health. Teeth in the maxillary left and right quadrants of the same dogs were ligated for 4 and 10wk respectively. Blood flow was measured by injecting radioisotope-labelled microspheres into the systemic circulation of each dog. After the microspheres had impacted, dogs were killed and blood flow was measured.
R: Experiment 1: Blood flow in healed, non-inflamed gingiva was significantly less than in inflamed gingiva. No differences in the blood flow of alveolar bone underlying inflamed or non-inflamed gingiva were present. Blood flow was significantly higher in gingiva than in alveolar bone. Experiment 2: Overt gingival inflammation was present around 75-100% of ligated teeth, while gingiva of cleaned, non- ligated teeth were clinically non-inflamed. Gingival blood flow was significantly increased by 54% around ligated teeth but bone blood flow remained unchanged. Duration of the ligation did not alter blood flow. There was a progressive increase in blood flow as GI increased. The difference in blood flow in gingiva with no BOP (GI>1) and gingiva with BOP (GI<2) was significant.
C: Changes in blood flow associated with inflammation are reversible. Blood flow in alveolar bone is regulated independently of gingival blood flow.
P: To evaluate dynamic changes in the gingival microvasculature following the development of partial mouth experimental gingivitis in human subjects.
Materials and methods:
· 10 male, 18-30 yrs old, good health subjects, upper anterior teeth examined
· Baseline data gathered and 12-16 days later data obtained after gingivitis developed. GI, PI, BOP and GCF volume were measured.
· Videomicroscopic and laser doppler techniques used to measure the # of visible vessels, and those with active flow, and red blood cell velocity.
· Vitals recorded as to rule out systemic influences
· Split mouth design
Results:
· Gingivitis developed in all subjects: increase in PI, GI, BOP and GCF volume.
· No change seen in superficial capillary red blood cell velocity as evaluated by videomicroscopic measures of individual vessels in marginal gingiva.
· SS decrease in regional gingival blood flow observed via doppler evaluation.
· Significant increase in the number of superficial vessels visible in a microscopic field during gingivitis.
· No differences between control and gingivitis states in the systemic cardiovascular and respiratory measures.
BL: No differences were seen in the parameters designed, therefore it can be assumed that the gingival vascular changes described were secondary to gingivitis itself. The data presented showing an increase of superficial vessel numbers and a decrease in Doppler flow in gingivitis are not necessarily contradictory to previous studies who failed to show histo differences in gingival vascular volume between control and gingivitis.
P: To detail the vascular supply to the floor of the mouth and lingual gingiva and to explain the relative contribution and importance of the sublingual versus the submental artery in humans.
M&M: 74 adult cadavers (52 men, 22 women) from 45-92 years of age were studied. All were white except one that was African-American and one Asian. Any branch 1/3 the diameter of the submental artery or larger was arbitrarily defined and recorded as a large branch. The presence of this large branch perforating the mylohyoid muscle indicated that it played a role in the arterial circulation ot the floor of the mouth. The diameter of the vessels were measured with a needle compass and millimeter ruler. The sublingual artery was recorded as (1) normal or (2) small, insignificant, or missing.
R: A large branch of the submental artery perforating the mylohyoid muscle was found in 74/124 dissections (59.7%). No large branch was found in the remaining 40%. Also, in 93% of the positive sides, the perforating branch was larger than ½ the diameter of the parent submental artery and thus could be considered the terminal branch. The point at which this branch perforated the mylohyoid muscle was on average 37mm posterior to the menton, measured along the inferior border of the mandible (range 20-55mm). In the floor of the mouth, 53% contained a small, insignificant, or missing siblingual artery. The remaining 47% had a normal sublingual artery. In all cases with a small, insignificant, or missing sublingual artery, a large perforating branch of the submental artery was found.
BL: The submental artery can be considered the main arterial blood supply to the floor of the mouth and mandibular lingual gingiva. Therefore, when a hemorrhage is present, the submental artery or its parent facial artery should first be ligated (if not sufficient, the lingual artery should then be ligated).
What causes stippling at the histologic level? Is the presence or absence of stippling important?
P: To study the location, individuality, microscopic appearance of stippling and its relation to gingival health, as well as differences in stippling between different age groups and genders.
M: 250 subjects with healthy gingiva and 50 with gingival pathology, 2.5-65 years of age, examination using a small magnifying glass. 20 of those with pathology were treated, gingival biopsies pre and post treatment.
R: In a certain individual the heaviest stippling will be in the upper labial followed by lower labial, lingual and then buccal. Stippling might occasionally appear in the free marginal gingiva but usually only in the attached gingiva. The attached gingiva covering the root area of the canine does not exhibit any stippling. Stippling is unique to the individual, Differences between genders are mainly in size where men have larger more pronounced. Stippling first appears at 6 years of age, increases in prevalence up to adolescence and starts to disappear in old age. Microscopically, stippled tissue appears alternating of elevations and depressions of the epithelium with high lamina propria projections in areas of thin elevated epithelium. The depressions exhibit a thick layer of epithelium. Stippled areas are highly keratinized. Only when inflammation progresses from the free gingival margin to the attached gingiva will stippling disappear, in 19/20 patients that were treated stippling reappeared
BL: Stippling might not always be present in health, but it might aid in diagnosis
What is the significance of gingival color?
P: Determine if color changes in gingiva can be used as a diagnosis of disease severity or chronicity
M: Denture acrylic made into different shades of gingival using dye mixes. 38 areas of 24 well maintained pts from 27-75 y.o were evaluated using the color wheel created. Biopsies were taken of each area and results compared to color wheel.
R: All biopsies diagnosed with chronic inflammation. Color evaluation varied throughout the color wheel spectrum w/ each separate specimen. Color is unreliable as indicator of severity. Keratosis of epithelium does not influence color. Long standing gingival inflammation tends to return to original pink color. Less red does not mean more severity and more blue does not mean more chronicity. Color is a useful diagnosis in gingivitis.
B.L: Color is useful in diagnosis of gingivitis, but not as an indicator of severity.
Is keratinized or attached gingiva necessary for health? If so, how much? Does the width of attached tissue change over time?
P: To determine if the width of attached gingiva varies with each tooth, each individual, age, sex, and to answer the following questions
what are the average and extreme widths of attached gingiva?
2) What factors affect the width of attached gingiva?
M: 160 subjects with the clinical signs of normal gingival included and separated into 4 age groups. 1) 3-5 y/o, 2) 15-25, 3) 25-35, 4) >35. 20 M and 20 F in each group. In addition 80 subjects w/ 1 or more of the following were examined: malposed teeth, high frenum attachments, and recession. Buccal and labial zone of attached gingiva was measured w/ periodontal gauge calibrated in mm’s.
Results and BL
No SSD b/w mean widths of attached gingival in M and F
Width of attached gingiva did vary b/w individuals.
Increase of attached gingival from deciduous dentition to adult dentition
Attached gingival ranged from < 1mm-9mm
Narrowest band in region of mandibular 1st bicuspid and cuspid
Widest band in max lateral and central incisors
-In subjects with no attached gingival the remaining tissue would curl and was freely movable and was usually inflamed
Teeth in labio or bucco-version had a narrower zone of att gingival, than properly aligned corresponding teeth on opposite side. Teeth in lingual version had a broader zone of att gingival.
Narrow widths assc. w/ high frenum and muscle att.
Areas of recession were also accompanied by narrow zones of att gingiva. In cases of moderate recession, there was often no att. gingiva. Clinical health can be observed in pt’s with <1mm attached gingiva
P: To examine the width of facial and lingual keratinized gingiva and to determine how much keratinized gingiva is adequate for the maintenance of gingival health.
M&M: 32 dental students, ages 19-29 years, no pockets and supervised oral hygiene for 6 weeks were included. After 6 weeks, gingival index (GI), plaque index (PI), width of KG and PDs were assessed. Gingival exudate was assessed on all buccal and lingual surfaces which had 2mm or less of KG and randomly selected tooth surfaces with KG 2.5-3mm. Only plaque free surfaces were scored.
R: After 6 weeks of controlled oral hygiene the mean individual PI was 0.22, the mean individual GI was 0.09. Average PD was 1mm and 1168/1406 tooth surfaces were completely plaque free. Facial KG was widest in the area of upper and lower incisors and narrowest adjacent to the maxillary and mandibular canines and 1st premolars. Lower premolars and molars showed the widest lingual gingiva, while the incisors showed the narrowest lingual gingiva. In the maxilla the facial gingiva was generally 0.5-1mm wider than in the mandible. Most surfaces (>80%) with 2mm KG were clinically healthy and 76% of these surfaces failed to show gingival exudation. All surfaces with <2mm KG exhibited signs of clinical inflammation and varying amounts of gingival exudate.
C: Gingival health is compatible with very narrow gingiva. However, in areas with <2mm KG gingival inflammation persisted in spite of effective oral hygiene. It is suggested that 2mm of KG (corresponding to 1mm attached) is adequate to maintain gingival health.
Schoo 1985
ARTICLE
P: To investigate changes in the position of the buccal soft
tissue margin of gingival recession.
M+M: Five year longitudinal study. 25 patients, 18-67
years old. Total of 106 buccal sites with localized recession and pockets< 3 mm.
73 mandibular and 33 maxillary teeth- 27 incisors, 32 canines, 41 premolars and
6 molars. Prior to baseline exam, all patients received initial tx: SRP, OHI
given, instructed atraumatic brushing technique with soft toothbrush. Examine
for recession, PD, and gingival width annually. The teeth (not patients) were
divided into two groups: group without attached gingiva (AG=0): 52 teeth, group
with attached gingiva (AG>0): 54 teeth.
R: After 5 years there was NSD between two groups for recession, pocket depth, attachment level and gingival width. No association between plaque or gingivitis and any other of the parameters. SS loss of attachment was found in the group with attached gingiva.
BL: The assumption that the presence of attached gingiva reduces the risk of further loss of attachment is questionable, surgical intervention should not be solely based on this parameter. When gingival recessions are present, elimination of traumatic oral hygiene habits will be enough to prevent further clinically significant loss of attachment and recession regardless of the width of the gingiva.
CR: Pt OH and gingival indices were not assessed throughout the 5 year study, and OH instruction was only given once prior to initial exam and never repeated again. Only after 5 yrs did they assess plaque, GI, and BOP.
P: To report the 5-year results from a previous study with respect to the position of the soft tissue margin at 26 buccal sites sx deprived of all gingival tissue.
M&M: The entire zone of gingiva was sx removed around 26 canine-PM teeth in the mandible of 6 pts. Following the sx, 14/26 of these sites were lacking attached gingiva (AG) and the remaining 12 sites had less than 1mm of AG. OH was “very controlled” for 6 months. In addition to these test areas, 2 areas per pt with >1mm AG were examined to serve as controls. The control sites were the buccal sites of the teeth adjacent to the test teeth. To evaluate the AG, the alveolar mucosa was stained with an iodine solution. Acrylic stents were made for guiding the perio probing. Pts were recalled every 6 months over 5 years.
R: The probing attachment level remained essentially unchanged over 5 years. An increase in rec was found in 1/14 test areas lacking AG and in 1/12 areas with <1mm AG. In adjacent controls (>1mm AG), 3 sites developed rec accompanied by a reduction of the width of the gingiva. A coronal re-growth of the soft tissue margin was observed in 7 of the test areas, out of which 3 areas also showed gain of PAL.
BL: In pts with adequate plaque control, the lack of AG does not result in an increased incidence of soft tissue recession. The authors feel that a narrow zone of gingiva apical to a localized rec is the consequence, rather than the cause of the rec.
P: To study the width of the facial AG in deciduous, transitional, & permanent dentitions.
M&M: Evaluated 331 individuals between 3-15 years old, all free of clinical inflammation, determined KG, PD, & amount of AG. Recession measured from CEJ to FGM.
R: Mean width of AG did not increase from the deciduous to permanent dentition. The width of AG was narrower in newly erupted permanent teeth. The widest zone of AG was found over the central and lateral incisors, decreased over the canine and 1st premolar, and increased over the 2nd premolar and 1st molar. Overall, greater AG in the maxilla.
BL: Increased AG in the permanent dentition was related to a concomitant decrease in sulcus depth by a coronal shift of CEJ level & coronal migration of the JE. Smallest width for AG in both primary and permanent teeth is in mand canines and 1st PM, widest is max lateral and 1st molar.
Does the thickness of keratinized tissue influence the surgical treatment plan?
Eger 1996 NO ARTICLE
Purpose: To determine the validity and reliability or measuring gingival thickness with an ultrasonic device, and to measure gingival thickness in relation to tooth type and age
Materials and Methods: Ultrasonic measurements were performed in 200 periodontally healthy, male subjects, representing 3 different age groups (20-25 , 40-45, 55-60). Each subject received an exam, oral hygiene instructions, a cleaning/scaling. 2 weeks later, measurements taken of probing depth, width of gingival, recession and crown length. Linear regression and correlation analysis was performed.
Results: There was a wide range of thicknesses ranging from 0.3 – 3.1 mm. In the maxilla, mean gingival thickness ranged from 0.9 mm (in canines and 1st molar) to 1.3 mm (2nd molars). In the mandible, they ranged from 0.8 (canines) to 1.5 mm (2nd molars). There were no differences noted between age ranges. In evaluating statistics of youngest age group, the variance in thickness was attributed to probing depth, recession, width of gingival, and tooth type.
Conclusions: There are individual differences in gingival thickness (based on different biotypes). Thickness mainly depends on tooth type and is correlated with width of gingival. Validity of measuring gingival thickness with the ultrasonic device was excellent.
P: To clinically determine the thickness of masticatory mucosa in the hard palate and tuberosity
as potential donor sites for ridge augmentation procedures
M: 31 healthy Caucasians (17 males 14 females, average age 35 years old), thickness measured through bone sounding using a periodontal probe 0.45 mm in diameter. Hard Palate: three lines drawn on casts 3, 8, and 12 mm away from and parallel to the gingival margin, with 6 measurements taken at each site corresponding to the midpalatal of canine and premolars, palatal root of first and second molars and interdentally between the molars. Tuberosity: two lines parallel to the distal gingival margin of second molar 2-6 mm respectively with three measurements on each. Measurements taken 30 minutes after local anesthesia (to avoid misreadings from increased volume of anesthetic in tissue).
R: No differences between genders except in one area (most distal area on the palate was thicker in females). Tuberosity area was thicker than the palatal mucosa, thinnest mucosa in the hard palate was over the palatal root of the maxillary first molar, thickest at the canine. Thickness increases as distance from the free gingival margin increased.
BL: in the canine-premolar region wide and shallow grafts might be harvested, if you extend distally the mucosa is going to become thinner close to the first molar which may act as an anatomical barrier, the maxillary tuberosity offers significantly thicker soft tissue for deep grafts.
Is keratinized tissue necessary for implants? Why or why not?
P: To study the morphogenesis of the mucosal attachment to implants made of c.p. titanium.
M&M: 20 Labrador dogs were included. All mandibular premolars were extracted. After a healing period of 3 months, 4 implants (ITI Dental Implant System) were placed into the right and left sides of the mandible. A non-submerged implant installation technique was used and the mucosal tissues were secured to the conical marginal portion of the implants with interrupted sutures. The sutures were removed after 2 weeks and daily plaque control program of the remaining teeth and the implants was initiated. The animals were sacrificed and biopsies were taken at day 0, day 4, 1 wk, 2 wks, 4, 6, 8, 12 wks. Histological analysis was performed.
R: Healing was uneventful following implant installation in all 160 sites. A coagulum occupied the area between the mucosa and the implant immediately after sx. At 4 days of healing the blood clot was infiltrated by numerous neutrophils granulocytes. At 2 weeks after surgery, the peri-implant mucosa adhered to the implant surface by a connective tissue that was rich in cells (fibroblasts was the dominating cell population in the CT interface but at 4 weeks the density of fibroblasts had decreased) and vascular structures. In the marginal portion of the tissue, proliferation of epithelium had occurred and the first signs of a barrier epithelium (junctional) were observed. At 4 weeks of healing, barrier epithelium had formed and occupied about 40% of the mucosa interface to titanium. The CT was well organized and contained large portions of collagen and fibroblasts. Bone remodeling had resulted in a distinct crestal bone portion of about 3.2mm apical of the soft tissue margin. Tissue maturation and collagen fiber organization was evident from 6-12 weeks of healing and the formation of barrier epithelium was completed between 6 and 8 weeks. A dense layer of elongated fibroblasts formed the connective tissue interface to titanium.
C: The soft tissue barrier adjacent to titanium implants placed using a non-submerged installation procedure developed its final characteristics within 6 weeks post-op. Before this time period, the establishment of the barrier epithelium and the maturation of CT may be incomplete.
P: To evaluate whether the width of the keratinized mucosa around implants supporting overdentures has a positive effect on the health of the surrounding soft and hard tissues.
M+M: 27 edentulous patients, 12M 15F, mean age 61 years old. 66 restored implants, with length 8-14mm and diameter 3.3-4.1mm. 24 implants in maxilla, 42 in mandible. Records and radiographs confirmed that the implants had been clinically successful for entire time before measurements took place. Patients were classified according to smoking status: 22 non-smokers, 3 current smokers and 2 former smokers. Clinical examination consisted of number and location of the implant, PI, GI, BOP, PD, PAL, Recession, radiographic bone levels and KG.
R: KG ranged from 0-6mm. A negative correlation was found between KG and recession. 36 implants had ≥2mm KG and 30 had <2mm. NSSD was found between the 2 groups with regards to PD and radiographic bone loss. SSD for PI, GI, BOP, recession and PAL.
BL: The absence of adequate KG around implants supporting overdentures was associated with higher plaque accumulation, gingival inflammation, bleeding on probing and recession.
CR: Statistically significant results, but clinically significant?
PURPOSE: To determine whether an association exists between the width of keratinized mucosa and the health of implant supporting tissues.
METHODS: Patients coming for biannual maintenance appointment were randomly selected. Total of 76 patients were used with 200 restored implants. 110 had >2 mm KG (group A). 90 had <2mm KG (group B). Implants had been in place for at least 12 months. A single examiner recorded location of implant, plaque index, gingival index, width of KG (at midfacial, roll technique used to establish MGJ), thickness of gingival tissue (2mm apical to gingival margin with 27 gauge needle with rubber stopper and UNC probe), probing depth (UNC probe), mobility, radiographic bone level, time since placement (years), and smoking history (packs per year).
RESULTS: Gingival index, plaque index, and radiographic bone level were significantly higher in group A than group B. No significant differences were noted in probing depth or smoking. Implants in group B had been restored significantly longer than those in group A. Implants with a narrower zone of KG were 3 times more likely to have BOP than those with a wider zone of KG and had higher mean alveolar bone loss.
DISCUSSION: Results showed that implants with narrower zones of KG (<2mm) had significantly more plaque and signs of inflammation (BOP) than those with wider zones of KG (>2mm). This supports the theory that narrow zones of KG are less resistant to insult due to mastication and frictional contact along the implant-mucosa interface.
CONCLUSION/BL: The findings of this study suggest that there is a relationship between width of KG and health of peri-implant tissues. Implants with less than 2 mm of KG showed higher BOP and alveolar bone loss that implants with wider zones of KG.
Cr: PAs were not standardized
Marquez 2004 NO ARTICLE
P: Review the variations in the width of keratinized tissue and attached gingival and their clinical significance regarding periodontal/peri-implant health. Historically a certain amount of attached gingiva has been considered necessary to maintain gingival health and prevent gingival recession. However there are considerable different opinions regarding when surgery is indicated for correcting gingival inadequacies. A functionally adequate band of KG and attached gingiva will effectively dissipate muscular and frenum pull and remain healthy without gingival recession occurring with normal function.
Attached gingiva = distance between gingival margin to the MGJ - depth of the sulcus or pocket
Width and Thickness of Gingiva
· Bowers study –width of gingival ranged from 1-9mm, values greatest at the incisor regions (with lateral being the greatest) and smallest at the canine and 1st premolar sites. Maxilla usually had a wider band than the mandible. Subjects with less than 1mm of attached gingiva displayed clinically healthy gingiva but the tissue usually was inflamed in areas where no attached gingiva was present. High frenum and muscle attachments were associated with narrow zones of attached gingiva.
· Andlin-Sobocki- longitudinal observations to confirm the pattern of facial keratinized tissue widths in children. Over a two-year period, primary and permanent teeth demonstrated an increase in the width of both facial attached and keratinized tissue. Zones of attached and keratinized tissue were narrower on facially positioned teeth than on well-aligned or lingually positioned teeth.
· Voight- Measured the width of lingually attached gingiva.
i. 1st and 2nd molars showed the greatest width (4.7mm)
ii. incisors and canines demonstrated the smallest width (1.9mm)
· Goaslind study – thickness of free gingiva averaged 1.56 mm (increased from anterior to posterior), and thickness of attached gingival averaged 1.25 mm.
Keratinized Tissue and Gingival Health
· Lang – a very narrow band of gingival is compatible with gingival health, inflammation persisted in areas with less than 2.0 mm of KG (1.0 mm AG) regardless of oral hygiene
· Miyasato – experimental gingivitis in areas of minimal keratinized gingival – this study found no apparent differences in plaque, gingival exudate and clinical gingival inflammation between areas with minimal KG (< 1 mm) compared to appreciable KG (> 2 mm)
Restorative Dentistry
Natural teeth
· Stetler and Bissada: evaluated periodontal condition of teeth whose submarginal restorations were associated with either narrow or wide zones of keratinized gingiva. Teeth with sub-g restorations and narrow zones of keratinized gingiva showed SS higher gingival scores than teeth with sub-g restorations and wide zones of keratinized gingiva. Teeth with no sub-g restorations showed no SSD between narrow and wide zones of kg.
· Dello Russo: it is best to place the lingual bar of partial removable denture as far from the marginal tissues as possible while maintaining contact with dense, collagenous attached gingiva.
Dental Implants
- Literature supports a sufficient zone of attached gingival is recommended for teeth to receive full- crown restorations. Same prerequisite for implants. A lack of masticatory mucosa and the presence of marginal nonkeratinized soft tissue often are associated with inflammation, which can result in peri-implant destruction.
Orthodontic Movement
· Boyd – Otho treatment is unlikely to result in increased amounts of KG.
· Maynard and Ochsenbein – recommend free gingival grafts prior to orthodontic movement to prevent recession in areas where attached gingival is 1 mm or less
· Artun and Krogstad reported recession associated with excessive proclination after orthodontic treatment
P: To compare intra- and inter-examiner reproducibility in measuring the apico-coronal dimension of kerainized tissue (KT) by using 3 different methods to identify MGJ location.
M&M:Fifteen patients 11 female, 4male, 22-75 years old. Inclusion criteria: at lease one tooth treated with gingival augmentation, at least one other tooth on the same arch without gingival augmentation. 17 teeth that received envelope flap plus CTG (surgery group) were compared to equal number of contralateral, non-treated teeth present in the same ach. Time elapsed from gingival augmentation procedure to KG assessment ranged fom 6-21 months. Two examiners at the same session measured the GI, Apico-coronal dimension of gingiva(KTW) via visual (VM), functional (FM) and visual after histochemical staining (iodine solution)(HM). The measurement were recorded using a customized block and with an unmarked caliper and transferred to a paper that was later measured under a dissecting microscope at 2x magnification. Data was analyzed via 3-way ANOVA, intra-class correlation coefficient.
R: Surgery sites had significantly higher width of KG. Intra-examiner reproducibility, ranged from .94 for VM to .99 for HM. Inter-examiner reproducibility reproducibility varied form .92 for VM to .98 for HM.
BL: All three methods for MGJ identification led to statistically and clinically similar recordings of KTW.