Gingival phenotypes in young male adults

Abstract In a previous study on 42 young adult, periodontally healthy subjects without any attrition, abrasion or crown restoration, gingival thickness (GTH) was determined at facial aspects of premolars, canines and incisors by a novel ultrasonic device. GTH strongly depended on periodontal probing depth, width of gingiva (WG), and tooth type. Whereas the ratio of crown width to its length (CW/CL) was not identified as an explanatory variable, a significant influence of the subject was ascertained. The aim of the present study was to extend these analyses in order to identify subjects with different morphological characteristics of gingiva, i.e., gingival phenotypes. When employing cluster analysis on standardized parameters mean GTH, WG and CW/CL of upper canines, lateral and central incisors, 3 clusters were identified. Cluster A comprised 2/3 of subjects, displaying “normal” GTH, WG and CW/CL. Cluster B (n=9, 21%) had a significantly thicker and wider gingiva, and a more quadratic form of upper front teeth. A 3rd cluster (cluster C, n=5, 12%) was identified showing “normal” GTH, high CW/CL, but a narrow zone of keratinized tissue. Some characteristics of gingival phenotype of the upper front tooth region were also found at upper premolars (WG, CW/CL) but in general not at mandibular teeth. Present results clearly indicate evidence for the existence of different gingival phenotypes. Clinical relevance of these observations has to be tested in longitudinal studies.     

Thickness of palatal masticatory mucosa associated with age.

BACKGROUND: The palatal masticatory mucosa is widely used as a donor material in periodontal plastic surgery. However, there are relatively few studies investigating the volume or thickness of the palatal mucosa. The purpose of this study was to determine the thickness of palatal masticatory mucosa in Asian subjects aged 14 to 59 years by a direct clinical technique. The associations of age and gender with the thickness of palatal mucosa were also examined. METHODS: Sixty-two systemically and periodontally healthy Asians (31 males; 31 females; age range 14 to 59 years) participated in this study. The younger age group (age 14 to 21 years) consisted of 32 subjects with a mean age of 16.8 years, whereas the older age group (age 30 to 59 years) consisted of 30 subjects with a mean age of 38.7 years. A bone-sounding method using a periodontal probe with minimal anesthesia and a prepared clear acrylic stent were utilized to assess the thickness of palatal mucosa at 15 measurement sites defined according to the gingival margin and mid-palatal line. Multiple linear regression analysis was performed to examine the associations of age and gender with the mean mucosal thickness at the subject level. The Wilcoxon test was used to determine the difference in mucosal thickness between the 2 age groups, and between gender at each measurement point. RESULTS: The mean thickness of palatal masticatory mucosa ranged from 2.0 to 3.7 mm. The younger age group had significantly thinner mucosa (mean 2.8 +/- 0.3 mm) than the older age group (mean 3.1 +/- 0.3 mm). Females had thinner mucosa than males in the same age group, but the difference was not statistically significant. Overall, the thickness of palatal mucosa increased from the canine to second molar areas and in the sites furthest from the gingival margin towards the mid-palate (with the exception of the first molar area, where significantly decreased thickness was observed). CONCLUSIONS: Within the limits of the present study, the canine and premolar areas appear to be the most appropriate donor site for grafting procedures in both young and adult individuals. The subepithelial connective tissue graft procedure can be considered as a treatment modality in young patients, since a sufficient volume of donor tissue can be obtained from the hard palate area. Other factors that may influence the thickness of palatal mucosa such as racial and genetic factors and body weight need to be further investigated.     

Masticatory mucosa and periodontal phenotype: a review

In recent years, the dimensions of different parts of the masticatory mucosa have become the subject of considerable interest in periodontics from both an epidemiologic and a therapeutic point of view. In the present article, the clinical relevance of the thickness of the masticatory mucosa for the development of gingival recessions, surgical root coverage, as well as graft harvesting will be reviewed. The concept of different periodontal phenotypes has recently been substantiated by experimental evidence using a novel, commercially distributed, ultrasonic measuring device. Based on observations made in a series of investigations, it has become clear that individuals with thin and vulnerable gingival tissue prone to the development of recession often also present with thin palatal mucosa that might not be very suitable for obtaining connective tissue of proper thickness for plastic periodontal surgery. Periodontal phenotypes are closely associated with, and are in fact an expression of, the so-called biologic width, which should be considered during subgingival placement of restorations in particular. Thus, a detailed analysis of the thickness of the masticatory mucosa may be necessary in several clinical situations.     

Thickness of posterior palatal masticatory mucosa: the use of computerized tomography

BACKGROUND: Periodontal plastic surgery is used to fulfill the esthetic and functional demands of patients. The palatal masticatory mucosa is the main donor site for connective tissue, and the thickness of the graft tissue obtained is an important factor for the success of this technique. The aim of this study was to measure the thickness of masticatory mucosa in the posterior palatal area using computerized tomography (CT). METHODS: The thickness measurements were performed on the images of 100 adult subjects who underwent CT on the maxilla for implant surgery. Twenty-four standard measurement points were defined in the hard palate according to the gingival margin and the middle palatal suture. The radiographic measurements were used after calibration. The data were analyzed to determine the differences in the mucosal thickness according to gender, age, tooth position, and depth of the palatal vault. RESULTS: The overall mean thickness of the palatal masticatory mucosa was 3.83 +/- 0.58 mm (range: 2.29 to 6.25 mm). Females had significantly thinner mean masticatory mucosa (3.66 +/- 0.52 mm) than males (3.95 +/- 0.60 mm) (P <0.0001). The thickness of the palatal masticatory mucosa increased with age. The mean thickness according to tooth site was 3.46 mm (maxillary canine), 3.66 mm (first premolar), 3.81 mm (second premolar), 3.13 mm (first molar), 3.31 mm (the base of the interproximal papilla of the first and second molars), and 3.39 mm (second molar). There was an overall increase in the thickness of the palatal masticatory mucosa as the distance from the gingival margin to the middle palatine suture increased, with the exception of the Ca-d (a point at 12 mm from the gingival margin of the canine) region. There was no significant difference in the thickness of the palatal masticatory mucosa between the groups with high or low palatal vaults. CONCLUSIONS: The palatal masticatory mucosa thickness increased from the canine to premolar region but decreased at the first molar region and increased again in the second molar region, with the thinnest area at the first molar region and the thickest at the second premolar region. The canine to premolar region seems to be the most appropriate donor site that contains a uniformly thick mucosa. CT can be considered an alternative method for the measurement of palatal soft tissue thickness.     

Soft tissue thickness for placement of an orthodontic miniscrew using an ultrasonic device

OBJECTIVES: To evaluate area- and gender-related differences in the soft tissue thickness of potential areas for installing miniscrews in the buccal-attached gingiva and the palatal masticatory mucosa. MATERIALS AND METHODS: The sample consisted of 61 Korean young adults. An ultrasonic gingival-thickness meter was used to measure the soft-tissue thickness in the buccal-attached gingiva just adjacent to the mucogingival junction of the upper and lower arches and 4 mm and 8 mm below the gingival crest in the palatal masticatory mucosa. Independent t-test, paired t-test, and one-way analysis of variance were used for statistical analysis. RESULTS: Buccal-attached gingiva thickness in the upper arch was significantly greater in men than in women, but buccal-attached gingiva thickness in the lower arch and palatal masticatory mucosa thickness 4 and 8 mm below the gingival crest did not show gender differences. Significantly thicker soft tissue occurred in the anterior areas in the upper arch and in the posterior areas in the lower arch. In the palatal masticatory mucosa, significantly thicker soft tissue was found 4 mm below the gingival crest in the anterior areas and 8 mm below the gingival crest in the posterior areas. The areas between the canines and the premolars showed higher values than other areas 4 mm below the gingival crest. However, the soft-tissue thickness 8 mm below the gingival crest showed a progressive increase from the anterior to the posterior areas. CONCLUSION: Measurements of the soft-tissue thickness using an ultrasonic device could help practitioners select the proper orthodontic miniscrew in daily clinical practice.     

On the relationship between crown form and clinical features of the gingiva in adolescents

Abstract The purpose of the present study was to examine the relationship between the form of the crowns in the maxillary front tooth segment and (1) a group of morphological characteristics and (2) the thickness of the gingiva. 108 subjects devoid of symptoms of destructive periodontal disease were examined regarding, e.g., probing depth, thickness of the free gingiva, width of the keratinized gingiva and the contour of the marginal gingiva. From clinical photographs of the maxillary front tooth region, the width (at the apical third – CW) and the length (CL) of the crowns of the 6 front teeth were determined. A CW/ CL-ratio was calculated for each tooth and averaged for each tooth region. The individual mean CW/CL-ratio values for the central incisors were ranked. After correction for incisal attrition, the 10 subjects ranked highest and the 10 ranked lowest were selected as having either a long-narrow (group N) or a short-wide (group W) form of the crown of the tooth. The data for each of the examined parameters were averaged for each tooth region in each subject and mean values for subjects in groups W and N were compared using the Student t-test. Stepwise multiple regression analysis, including data from the whole sample, was performed for each tooth region with the thickness of the free gingiva as the dependent variable. The results from the analyses demonstrated that individuals with a long-narrow form of the central incisors displayed, compared to individuals with a short-wide crown, form (i) a narrow zone of keratinized gingiva, (ii) shallow probing depth, and (hi) a pronounced “scalloped” contour of the gingival margin. There was no significant difference between groups N and W with respect to the thickness of the free gingiva. The CW/CL-ratio data revealed that a certain form of the crowns in the central incisors was accompanied by a similar form in the lateral incisor and canine tooth region. The regression analyses demonstrated that the thickness of the free gingiva in central incisors was significantly related to (i) the width of the keratinized gingiva, (ii) the buccolingual width of the crown and (iii) the presence of an interproximal gingival groove. In lateral incisors, the thickness of the free gingiva was associated with the probing depth at the buccal surface. No single variable was significantly related to the thickness of the gingiva in canines.     

Thickness of masticatory mucosa

BACKGROUND: The aim of the present study was to assess thickness of all parts of the masticatory mucosa by using an ultrasonic measuring device. METHODS: A total of 40 periodontally healthy subjects, 19 to 30 years old, took part. Thickness of masticatory mucosa was measured at a maximum of 149 sites in each proband. RESULTS: Female volunteers had significantly thinner mean masticatory mucosa than males (p<0.01). Mean thickness of facial gingiva ranged between 0.7 mm at canines in the maxilla and central incisors in the mandible and 2.3 mm at 3rd molars in the mandible. In the mandible, thickness of lingual gingiva ranged between 0.9 mm at lateral incisors and 2.3 mm at 3rd molars. Interdental gingiva ranged between 1.0 mm 2.1 mm. With 3 mm or more, on average, palatal masticatory mucosa was thickest in the 3rd molar region and at 2nd premolars at more central locations. 2 regions with comparatively thin palatal mucosa of about 2 mm were identified, namely (i) at central and lateral incisors and (ii) at the prominence of the palatal roots of 1st and 2nd molars. The thickest tissue with more than 4 mm, on average, was observed in the tuberosity and retromolar regions. CONCLUSIONS: Considerable intra- as well as interindividual variation of thickness of masticatory mucosa could be observed. According to differences in thickness of facial and interdental gingiva, it appears that lining is also an important function of the gingiva in reducing and smoothing the pronounced convexities of the dentoalveolar, i.e., skeletal, complex.     

The gingival biotype revisited: transparency of the periodontal probe through the gingival margin as a method to discriminate thin from thick gingiva

Aim: To detect groups of subjects in a sample of 100 periodontally healthy volunteers with different combinations of morphometric data related to central maxillary incisors and surrounding soft tissues. Material and Methods: Four clinical parameters were included in a cluster analysis: crown width/crown length ratio (CW/CL), gingival width (GW), papilla height (PH) and gingival thickness (GT). The latter was based on the transparency of the periodontal probe through the gingival margin while probing the buccal sulcus. Every first volunteer out of 10 was re‐examined to evaluate intra‐examiner repeatability for all variables. Results: High agreement between duplicate recordings was found for all parameters, in particular for GT, pointing to 85% (κ=0.70; p=0.002). The partitioning method identified three clusters with specific features. Cluster A1 (nine males, 28 females) displayed a slender tooth form (CW/CL=0.79), a GW of 4.92 mm, a PH of 4.29 mm and a thin gingiva (probe visible on one or both incisors in 100% of the subjects). Cluster A2 (29 males, five females) presented similar features (CW/CL=0.77; GW=5.2 mm; PH=4.54 mm), except for GT. These subjects showed a clear thick gingiva (probe concealed on both incisors in 97% of the subjects). The third group (cluster B: 12 males, 17 females) differed substantially from the other clusters in many parameters. These subjects showed a more quadratic tooth form (CW/CL=0.88), a broad zone of keratinized tissue (GW=5.84 mm), low papillae (PH=2.84 mm) and a thick gingiva (probe concealed on both incisors in 83% of the subjects). Conclusions: The present analysis, using a simple and reproducible method for GT assessment, confirmed the existence of gingival biotypes. A clear thin gingiva was found in about one‐third of the sample in mainly female subjects with slender teeth, a narrow zone of keratinized tissue and a highly scalloped gingival margin corresponding to the features of the previously introduced “thin‐scalloped biotype” (cluster A1). A clear thick gingiva was found in about two‐thirds of the sample in mainly male subjects. About half of them showed quadratic teeth, a broad zone of keratinized tissue and a flat gingival margin corresponding to the features of the previously introduced “thick‐flat biotype” (cluster B). The other half could not be classified as such. These subjects showed a clear thick gingiva with slender teeth, a narrow zone of keratinized tissue and a high gingival scallop (cluster A2).     

The influence of gingival dimensions on bleeding upon probing in young adults with plaque-induced gingivitis

In both cross-sectional and longitudinal studies of young adults with plaque-induced gingivitis it has been observed that bleeding upon probing is only weakly associated with supragingival plaque. It has been speculated that gingival bleeding may be influenced by several independent factors other than plaque. Great intra- and interindividual variation of gingival thickness and width has been reported. Based on respective observations, the existence of different gingival phenotypes has been suggested. The aim of the present study was to investigate the possible influence of gingival thickness and width on bleeding on probing. Forty young adults with mild, plaque-induced gingivitis, 24 non-smokers and 16 smokers, participated in this cross-sectional study. In addition to periodontal probing depth, clinical attachment loss, width of gingiva, bleeding on probing, and presence of plaque, gingival thickness was measured with an ultrasonic device. Multivariable models were separately calculated for buccal, mandibular lingual, and palatal surfaces and generally adjusted for tooth type. Generalised Estimation Equation methodology was employed in order to adjust for correlated observations. Plaque was significantly associated with bleeding upon probing only at buccal sites (odds ratio 1.80, 95% confidence interval 1.19-2.72) An influence of similar magnitude was identified for smoking (odds ratio 1.76; 1.07-2.89). At lingual sites in the mandible, bleeding was influenced by smoking (odds ratio 2.25; 1.18-4.25) and gingival thickness (odds ratio for thick gingiva >1 mm of 1.93; 1.02-3.65), but not plaque. At palatal sites, only periodontal probing depth had an influence (odds ratio 1.89; 1.25-2.84). It was concluded that, apart from supragingival plaque, smoking was an independent risk factor for gingival bleeding on probing. Thin and vulnerable gingiva of insufficient width was not more likely to bleed after probing than thicker tissue.     

Ultrasonic determination of thickness of masticatory mucosa: a methodologic study.

OBJECTIVE: The aim of the present study was to assess the reliability and validity of ultrasonic measurements of thickness of the masticatory mucosa. STUDY DESIGN: Eleven periodontally healthy subjects took part. Thickness of the buccal gingiva was assessed midbuccally and interdentally. In the maxilla, the palatal mucosa was measured at every tooth midpalatally, between the first and second molars, and between the second and third molars at each of 3 defined locations 4 mm apart. In the mandible, thickness of the lingual gingiva was measured midlingually as well as interdentally between the first and second molars and between the second and third molars. Thickness of the retromolar mucosa was also assessed. All 1,293 measurements were repeated after 24 hours. Validity of measurements was tested in a porcine model. RESULTS: Mean (+/- standard deviation) thickness of the midbuccal and midlingual gingiva was 0.99+/-0.52 mm; the measurement error was 0.26 mm. Measurements were well correlated (Pearson's r = .74, P<.001). Mean thickness of the papillary gingiva was 1.19+/-0.53 mm; the measurement error was 0.37 mm (r = .58, P<.001). A lower reliability was observed for palatal measurements of mucosal thickness; mean thickness was 2.36+/-0.87 mm, and measurement error was 0.54 mm (r = .64, P<.001). The validity of measurements was excellent in the 0.5-4.5 mm range. CONCLUSIONS: Differences in reliability of ultrasonic assessments of mucosal thickness in different parts of the oral cavity may depend on the difficulties of repeatedly measuring at the same location, on varying thickness of the tissues, and on expression of palatal rugae. These problems might be resolved by averaging multiple measurements.     

基于冠龈形态特征的牙周表型的分类研究

纳入87名牙周健康的青年志愿者,测量并记录上前牙区以下数据:牙龈厚度(GT)、角化龈宽度(GW)、龈乳头高度(PH)和牙冠宽长比(CW/CL),用聚类分析法对牙周表型归类.结果提示在一定的中国汉族青年人群中,分别存在着薄扇型(Ⅰ,n=31)、厚平型(Ⅲ,n=8)和中间型(Ⅱ,n=48)3种牙周表型.     

Variance components of gingival thickness

OBJECTIVES: Distinct periodontal phenotypes have been identified by cluster analysis, which is an explorative method with very low external validity. The aim of the present study was to investigate variance components of facial gingival thickness in young adults with mild gingivitis. MATERIAL AND METHODS: Thirty-three non-smoking females, 18-23 years of age, with mild or moderate plaque-induced gingivitis participated. Gingival thickness was measured at every tooth present by use of ultrasound technology to the next 0.1 mm with a lowest measurement of 0.5 mm. Periodontal probing depth and clinical attachment level were measured with a pressure-controlled probe. Gingival bleeding index was assessed after probing on a 0-2 scale, where 1 was slight, and 2 was profuse bleeding on probing. The Silness-Loe plaque index was recorded. Multilevel variance components and random intercept models were built. RESULTS: A 2-level (subject, tooth) variance component model of gingival thickness without any explanatory variable revealed an intercept (mean) of 0.93 +/- 0.02 mm. Subject variation of gingival thickness amounted to 4.2% of the total variance. Addition of tooth- and subject-related covariates to the model revealed, after adjusting for tooth type, an association with periodontal probing depth (estimated coefficient 0.067 +/- 0.025), and considerable association with average bleeding index (-0.395 +/- 0.149) and plaque index (0.125 +/- 0.048). Variation at the tooth level was drastically reduced; subject variation amounted to 5.2%. CONCLUSION: Gingival thickness is mainly associated with tooth-related variables. Bleeding tendency is higher if gingiva is thin. Subject variability related to periodontal phenotype may add to the total variance, however, to a very low extent.     

中国汉族成人后牙区硬腭黏膜厚度测量及各组织学层次分布规律研究

目的 本文测量中国汉族人群中后牙区硬腭黏膜的厚度,分析其变化规律及相关因素,观察硬腭黏膜固有层结缔组织各组织学层次的厚度、特点及分布规律。方法 36例患者根据牙龈生物型（gingiva biotype）分为三组,使用骨探测法（bone sounding）测量由尖牙至第二磨牙腭侧共45个位点硬腭黏膜的厚度,采集牙周软组织增量手术中移植软组织修剪下来的剩余组织,筛选具有硬腭黏膜全层的样本,采用免疫组化技术,镜下观察结缔组织的组织学特点及分布规律。结果 硬腭黏膜平均厚度(3.52±1.02）mm、尖牙区为(3.26±0.81）mm、第一前磨牙区为(3.57±1.05）mm、第二前磨牙区为(3.72±1.04）mm、第一磨牙区为(3.33±0.96）mm、第二磨牙区为(3.73±1.11）mm;硬腭黏膜的厚度与性别、年龄无显著相关性,与牙龈生物型之间存在统计学差异;HE染色显示硬腭黏膜结缔组织层具有致密的胶原纤维,由第二前磨牙区域开始出现明显的黏膜下层,在第一磨牙区域多见疏松结缔组织,内含大量脂肪组织、血管、腺体等。结论 在中国汉族人群中硬腭黏膜厚度由尖牙向后逐渐增厚,在第一磨牙区变薄,向第二磨牙区再次变厚;在尖牙、第一前磨牙和第二磨牙区可见由龈缘向腭中缝处黏膜厚度逐渐变厚;硬腭黏膜固有层含有致密的结缔组织,由第二前磨牙区开始出现黏膜下层,含大量脂肪组织、血管、腺体等。     

Periodontal status of ectopic canines after orthodontic treatment

Objective: To evaluate the periodontal health and tooth vitality of palatally impacted and buccal ectopic maxillary canines after completion of orthodontic treatment.Materials and Methods:Fifteen patients who had unilateral, palatally impacted canines and 15 patients who had unilateral, buccal ectopic canines comprised the subjects of the study. Clinical and radiographic data was collected by recalling the patients in both groups after a mean period of 3.82 ± 1.54 years following completion of their orthodontic treatment. In both groups, the contralateral, normally placed canines served as controls.Results:Palatally impacted canines had greater pocket depths, higher gingival levels, higher electric pulp testing scores, and reduced bone levels compared to their contralaterals. Buccal ectopic canines had increased plaque and gingival bleeding index, greater pocket depths, reduced attached gingival width, higher gingival levels, increased clinical crown lengths, and higher electric pulp testing scores compared to their contralaterals. Buccal ectopic canines had lower electric pulp testing scores and higher bone levels compared to palatally impacted canines.Conclusion:All ectopic canines had increased plaque and gingival bleeding index, greater pocket depths, reduced attached gingival width, higher gingival levels, increased crown lengths, higher electric pulp testing scores, and reduced bone levels compared to their contralaterals.     

Two years oral use of chlorhexidine in man

Possible changes in the structure of human oral mucosa resulting from exposure to chlorhexidine were examined in biopsy specimens of palatal and gingival mucosa obtained from three groups of young adults who had rinsed for more than 1 year (a) once or (b) twice daily with 0.2 % chlorhexidine solution or (c) with a placebo mouthwash. Specimens were quenched in liquid nitrogen and cryostat sectioned perpendicular to the epithelial surface. Sections stained with hematoxylin and eosin were used to assess the degree of keratinization of epithelia and to measure the width of the stratum corneum. Sections treated with buffered alkaline solutions were used to expand and count the number of layers of cells in the stratum corneum.
All specimens examined showed evidence of keratinization and, in keeping with previous reports, palatal specimens were more frequently orthokeratinized than gingival specimens. Mean width of the stratum corneum of gingival specimens was approximately 13 μ m and of palatal specimens, 23 μ m. The mean number of layers of cells in the stratum corneum of the gingiva was approximately 10 and of the palate, approximately 12. Differences in the degree of keratinization and thickness of the stratum corneum between gingival and palatal specimens was statistically significant, but no statistically significant differences were found between the chlorhexidine-exposed and non-chlorhexidine-exposed palatal tissue in keratinization, layers of cells or thickness of the stratum corneum. Neither was there any statistical difference in the same parameters for the gingival specimens. The methods employed did not therefore detect any changes in the normal structure of keratinizing oral epithelia as a result of prolonged daily exposure to chlorhexidine.     

Thickness of facial gingiva.

Gingival thickness was measured in 10 subjects with healthy gingiva on the facial aspect of selected maxillary and mandibular teeth at the depth of the gingival sulcus and midway between the sulcus depth and mucogingival line. Measurement instrumentation, consisting of a differential transformer coupled to an oscillator and digital voltmeter was sensitive to the travel of a probe from the gingival surface to tooth surface or alveolar bone. The probe assembly was accurate to 0.01 mm and the average range of differences in replicate measurements under a variety of conditions never exceeded 0.15 mm. 1. Free gingival thickness averaged 1.56 mm + 0.39, attached gingival thickness averaged 1.25 mm + 0.42 and the total mean thickness for all areas measured was 1.41 mm. 2. Thickness in mandibular free and attached gingiva and maxillary free gingiva increased from anterior to posterior. Thickness in maxillary attached gingiva remained fairly constant. 3. Thickness measured at the depth of the sulcus was directly proportional to the free gingival width. 4. Thickness measured midway between sulcus depth and mucogingival junction was inversely proportional to attached gingival width.     

Ultrasonic determination of gingival thickness

Abstract The objectives of the present study were (I) to determine the validity and reliability of measuring gingival thickness (GTH) with a recently developed, commercially available ultrasonic device: (II) to measure GTH in relation to tooth type and age of proband;(III) to correlate GTH with varying forms of pre-molars, canines and incisors. Ultrasonic measurements were performed in 200 periodontally healthy, male probands representing 3 different age groups (20–25, 40–45, 55–60 years). In the maxilla, mean GTH varied between 0.9 mm (canines, 1st molars) and 1.3 mm (2nd molars). In the mandible respective mean values ranged between 0.8 mm (canines) and 1.5 mm (2nd molars). No differences in means and standard deviations (0.36–0.39 mm) were observed in different age groups. In order to correlate GTH with other clinical parameters and form of tooth, in 42 probands of the youngest age group, presenting with no attrition or abrasion, no artificial crown restorations and (following prophylaxis) no overt gingivitis and no periodontal probing depth in excess of 3 mm. detailed clinical measurements and stone model cast analyses were performed. By stepwise multiple linear regression analysis, 24% (p < 0.0001) of the variation of GTH was explained by probing depth, recession, width of gingiva and tooth type. The ratio of the width of the crown to its length was not included into the model. When performing analysis of covariance with the subject as factor, the model was improved, now explaining 41% of the variation of GTH. In this model, the influence of periodontal probing depth was decreased, and recession was not included. It was concluded that there are individual differences in GTH (i.e., different biotypes). However, thickness mainly depends on tooth type and is correlated with width of gingiva. There appears to be no association with shape and form of the tooth. Validity and reliability of measuring GTH with the ultrasonic device was found to be excellent.     

A possible influence of gingival dimensions on attachment loss and gingival recession following placement of artificial crowns

The aim of the present study was to determine the influence of gingival dimensions on the development of gingival recession following placement of artificial crowns. The study population consisted of 11 periodontally healthy patients in whom 44 maxillary anterior teeth and/or premolars had to be crowned. A total of 36 teeth (82%) had, after crown placement, a mean intracrevicular crown margin of 0.57 +/- 0.47 mm. Thirty-nine teeth without restorations served as controls. Immediately after incorporation, as well as after 3, 6, 9, and 12 months, periodontal examinations were carried out. Gingival thickness was determined sonometrically and averaged 1.25 +/- 0.40 mm. Mean periodontal probing depth was 1.80 +/- 0.54 mm. Twelve months later, crowned teeth had experienced a mean attachment loss of 0.17 +/- 0.99 mm as compared to an attachment gain of 0.18 +/- 0.46 mm at control teeth. At test teeth, the gingival margin had receded a mean of 0.43 +/- 0.74 mm. In multivariate analyses considering the correlated structure of the data employing generalized estimating equation methods, crown placement was identified as a major factor for attachment loss and development of gingival recession. In addition, a shallow probing depth and narrow band of gingiva negatively influenced the level of periodontal attachment. The present results point to the importance of a more detailed periodontal diagnosis of the dentogingival region before placement of artificial crowns.     

A new method to assess and measure palatal masticatory mucosa by cone-beam computerized tomography

Aim: The aim of this study was to apply a novel method to obtain high-quality images by cone-beam computerized tomography (CBCT) that consistently allowed the determination of the dimensions of the palatal mucosa.
Materials and Methods: Thirty-one patients participated in this study. At the time of the CBCT scanning, the patients wore a plastic lip retractor and wooden spatulas to retract soft tissues away from the teeth and gingiva. The thickness of the palatal mucosa was obtained at forty different locations on each patient.
Results: Retraction of the lips and cheek allowed a clear observation and measurements of the thickness of the palatal masticatory mucosa. The average thickness of the palatal mucosa was 2.92 mm in the canine area, 3.11 mm at the first pre-molar, 3.28 mm at the second pre-molar, 2.89 mm at the first molar and 3.15 mm at the second molar. Statistical differences were observed at different ages and heights of measurements.
Conclusions: A new non-invasive method to consistently obtain high-quality images of the palatal masticatory mucosa is described. Measurements of this mucosa could be obtained at different locations on the palate.     

Development of gingiva following surgical exposure of a facially positioned unerupted incisor

A case with a facially positioned, unerupted maxillary incisor is presented as an illustration of the potential of the periodontal tissues to establish a zone of gingiva following surgical intervention. Despite the fact that the tooth had an erupting position entirely within the area of the alveolar mucosa, a zone of keratinized gingiva developed following surgical exposure of the crown of the tooth. This healing potential should be considered when selecting the treatment for facially positioned, unerupted teeth.