Periodontal characteristics in individuals with varying form of the upper central incisors

It has been suggested that the variation in the morphology of the human periodontium may be related to the shape and form of the teeth. Furthermore, the severity of symptoms of periodontal disease have been proposed to differ among these various morphologic entities or "biotypes". The aim of the present study was (i) to identify individuals with markedly different crown forms and (ii) to determine probing pocket depth, probing attachment level and amount of gingival recession that had occurred at different teeth and tooth surfaces in such individuals. Clinical photographs of the maxillary incisor tooth region of 113 subjects who had been recruited for a long-term study on periodontal disease were available. The length (CL) and width (CW) of the crowns were determined and the CW/CL ratio was calculated for each tooth. 10% in each tail, 11 subjects in each group, were arbitrarily chosen as having either a long-narrow (N) or a short-wide (W) form of the central incisors. The probing pocket depth, probing attachment level and gingival recession data available from all subjects and subjects in groups W and N were compared and analyzed using the Student t-test and multiple regression analysis. The result from the analyses demonstrated that: (1) subjects with a long-narrow form of the upper central incisors had experienced more recession of the gingival margin at buccal surfaces than subjects who had a short-wide tooth form; (2) there was a significant influence of the CW/CL-ratio on the probing attachment level (p less than 0.05) and the amount of gingival recession (p less than 0.01) on buccal tooth surfaces.(ABSTRACT TRUNCATED AT 250 WORDS)     

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).     

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.     

Morphological changes in the attached and keratinized gingiva and gingival sulcus in the mixed dentition period

Abstract A longitudinal study was undertaken to examine the changes in the sulcus probing depth, keratinized and attached gingiva during the mixed dentition period. 54 children aged 7 to 9 years at the first examination were examined twice, with an interval of 5 years. Sulcus probing depth and keratinized gingiva were examined at the buccal aspect of the incisors, and either right or left cuspids and posterior areas. The width of the attached gingiva was obtained by substracting the probing depth from the width of the keratinized gingiva. When compared to primary predecessors, the permanent teeth had a deeper probing depth, narrower attached gingiva and at the maxillary teeth, a wider keratinized gingiva. When a pennanent tooth was present at both examinations, there was a significant increase in width of the attached gingiva with a corresponding decrease in probing depth, and a slight beginning of an increase in the width of keratinized gingiva. Previous and the present findings indicate that during the early years after eruption of the permanent tooth, an increase in width of the attached gingiva takes place, without occlusal migration of the marginal gingiva whereas, at later stages, this coronal migration takes place, concomitant to tooth eruption.     

改良根向复位瓣技术在上颌后牙区种植二期手术中的应用效果评价

目的 探讨上颌后牙区种植体颊侧角化龈重建方法,评估其临床疗效及对种植体牙周状况的影响。方法 筛选种植二期手术且伴有角化龈不足的患者11例,共11个上颌后牙区种植位点,应用改良根向复位瓣技术在种植二期手术同期为患者进行角化龈重建。于二期手术后6周进行冠修复,并于冠修复3个月后复诊。分别记录术前、冠修复时和冠修复完成3个月后的角化龈宽度。拍摄根尖片,测量牙周探诊深度（PD）和探诊出血位点百分比（BOP）。采用SPSS 19.0软件包对数据进行配对样本t检验。结果 冠修复完成时,角化龈宽度为（3.30±0.36） mm,术前为（1.44± 0.34）mm,平均增加1.86 mm（P<0.01）。重建的角化龈宽度在冠修复3个月后仍然保持稳定,平均（3.34±0.33） mm（P=0.58）,无明显炎症与骨吸收。PD为（2.83±1.20） mm,BOP比为18.2%。结论 在种植二期手术同期,采用改良根向复位瓣技术能有效重建上颌后牙区种植体颊侧附着龈,短期内可以保证良好、稳定的效果。     

120名汉族青年前段牙弓唇侧角化龈宽度的测量

目的 通过测量获取前段牙弓唇侧角化龈和附着龈宽度的相关数据,以期为牙周解剖和牙周手术提供参考.方法 选择20～30岁牙龈健康的汉族青年120人,分别测量前段牙弓唇侧龈缘高点处角化龈宽度及龈沟深度、邻间牙龈乳头尖端处冠根向角化龈宽度,并对数据进行统计学分析.结果 龈缘高点相应处角化龈宽度在上颌前段牙弓最宽可达(5.6±1.3)mm,在下颌前段牙弓最宽可达(4.5±1.1)mm,且以切牙区最宽,尖牙、第一前磨牙其宽度逐渐变窄,第二前磨牙开始增宽;上、下颌前段牙弓邻间牙龈乳头尖端相应处冠根向角化龈宽度范围分别为(6.2±1.3)～(8.9±1.4)mm及(5.8±1.0)～(7.6±0.9)mm.结论 本组汉族青年前段牙弓唇侧龈缘高点相应处角化龈宽度和附着龈宽度因人和牙位而异;由于唇系带的附着,两中切牙邻间牙龈乳头尖端相应处冠根向角化龈宽度最窄.     

下颌后牙区不同时机游离龈移植的效果对比

目的对不同时机的游离龈移植术（FGG）增加下颌后牙区种植体周颊侧角化龈的临床效果进行评价。 方法选择2018年10月至2020年10月就诊于东莞健力口腔医院修复种植科下颌后牙区单牙缺失角化牙龈不足的患者（宽度为2 ~ 4 mm）共40例,将纳入的40例患者进行编号,以随机数字表法抽取20例为实验组,其余20例为对照组。实验组种植Ⅰ期手术时放置愈合基台同期行FGG。对照组种植Ⅰ期手术潜入式愈合,3个月Ⅱ期手术时放置愈合基台同期行FGG。术后观察移植物的存活情况,测量术前牙槽嵴顶剩余角化龈宽度,测量颊侧FGG后即刻、移植术后2个月、戴牙后即刻和戴牙后6个月的颊侧角化龈宽度,使用SPSS 20.0软件对移植物存活率、颊侧不同时间点角化龈宽度等进行统计分析,采用配对t检验进行比较,以P<0.05认为差异有统计学意义。 结果两组手术均获得成功,伤口正常愈合,组织瓣均存活。术前实验组和对照组牙槽嵴顶余留角化龈宽度分别为（2.9 ± 0.3）和（3.0 ± 0.3）mm,差异无统计学意义。实验组和对照组术后即刻种植体颊侧龈缘中点角化龈宽度分别为（4.9 ± 0.5）和（4.9 ± 0.5）mm,差异无统计学意义（t = 0.2,P = 0.8）。实验组和对照组术后2个月颊侧龈缘中点角化龈宽度分别为（4.2 ± 0.4）和（4.5 ± 0.4）mm,差异有统计学意义（t = -2.9,P<0.05）。实验组和对照组戴牙当天种植体颊侧龈缘中点角化龈宽度为（3.2± 0.4）和（3.7± 0.5）mm,差异有统计学意义（t = -2.6,P<0.05）。实验组和对照组戴牙后6个月种植体颊侧龈缘中点角化龈宽度为（3.1 ± 0.4）和（3.5 ± 0.3）mm,差异有统计学意义（t = -3.7,P<0.05）。 结论当下颌后牙区剩余角化龈为2 ~ 4 mm时,FGG在种植Ⅰ期手术同期及Ⅱ期手术同期均能获得较好的增加角化龈的效果。相比于种植Ⅰ期手术同期进行FGG,Ⅱ期手术同期FGG能获得更好的颊侧角化龈的宽度,但会增加手术次数。     

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.     

Mucogingival changes resulting from mandibular incisor tooth movement.

This study involved a cephalometric analysis of 1,150 fully treated orthodontic cases evaluated by Kodachrome slides, plaster casts, and cephalometric films to determine changes in the width of keratinized gingiva relative to lower incisor tooth movement and to ascertain the incidence of mucogingival problems in orthodontic patients. It was apparent that in a small percentage of cases visible mucogingival changes occurred and could be statistically correlated with the magnitude and direction of tooth movement. In this group of patients 1.3 percent (sixteen) showed a decrease in the width of keratinized gingiva with either minimal movement or some labial movement of the mandibular incisors; 0.69 percent (eight) had an increase in keratinized gingival width concomitant with significant lingual positioning of the lower incisors. The salient point to be made is that with an initial minimal or inadequate width of keratinized gingiva (0 to 2 mm.), mandibular incisor tooth movement over a period of treatment could significantly affect the final quality of gingival health in the critical mandibular anterior region.     

3-year observations on gingival recession in mandibular incisors in children

28 children aged 6-13 years, with gingival recession localized to mandibular incisors, were monitored longitudinally to evaluate any changes of the labial periodontal tissues. Measurements included dental plaque, gingival inflammation, gingival recession, probing depth, probing attachment level, keratinized and attached gingiva. Following baseline examination, the incisors were observed at yearly intervals over 3 years. The results showed that a high level of oral hygiene was maintained and that gingival inflammation occurred only to a minor degree throughout the observation period. Gradual reductions in the amount of gingival recession and probing attachment levels took place in all children except for 1 of the subjects with 1 severely malpositioned tooth. Probing depths and widths of keratinized and attached gingiva remained relatively unchanged. The finding that gingival recession in mandibular incisors in young children often improves over time suggests that preventive or reparative treatment in this part of the developing dentition may not be necessary. Decisions about such treatment should be postponed until any spontaneous improvement has taken place.     

Masticatory mucosa in subjects with different periodontal phenotypes

AIMS: The aim of the present investigation was to study thickness of masticatory mucosa and gingival width in subjects with different periodontal phenotypes. METHODS: Periodontal phenotypes were defined with the aid of cluster analysis of standardised parameters including mean gingival thickness and width as well as ratio of crown width to its length at maxillary canines, lateral and central incisors of 40 young adults with healthy periodontal conditions. RESULTS: 3 groupings could be observed. Clusters A1 and A2 comprised 75% of all subjects. They were characterised by thin gingiva and a slender tooth form. Clusters A1 and A2 were differentiated by gingival width. Cluster B comprised 11 subjects with relatively thick and wide gingiva and a quadratic tooth shape. In general, characteristics of the frontal sextant in the maxilla were also found in other parts of the dentition. Thus, mean thickness of masticatory mucosa as well as gingival width and crown form differed significantly among clusters. In addition, cluster B subjects had a significantly greater mean periodontal probing depth. Multiple linear regression analysis was employed to identify significant factors influencing palatal mucosal thickness. Women had considerably thinner palatal mucosa than men. Furthermore, cluster affiliation had a significant influence on thickness of palatal mucosa. Thickest tissue was found in the premolar region, whereas the mucosa over the root prominence of the first molar represented an anatomical barrier for graft harvesting. CONCLUSIONS: Thickness of masticatory mucosa strongly depends on gender and the periodontal phenotype.     

Dimensional alterations of the gingiva related to changes of facial/lingual tooth position in permanent anterior teeth of children

Abstract Maxillary and mandibular anterior permanent teeth in 38 children aged 7–12 years were examined 2 × with an interval of 2 years to determine whether spontaneous facial/lingual tooth position changes were related to alterations of the widths of keratinized and attached gingiva and the clinical crown height. Measurements included dental plaque, gingival inflammation, probing depth, and width of keratinized and attached gingiva. In addition, study casts from the baseline and 2-year examinations were used to measure clinical crown height and tooth position. The results showed that significant alterations in the widths of the keratinized and attached gingiva took place when the teeth changed positions in facial or lingual directions. The changes in gingival widths could to some extent be coupled to changes in clinical crown height. In teeth moving lingually, the gingival widths increased and the clinical crown height decreased. In teeth moving facially, the gingival widths decreased, and the facial gingiva sometimes receded. These gingival alterations call for examination of the facial gingiva as part of the monitoring of the development of the permanent dentition.     

INFLUENCE OF CROWN SHAPE ON ROOT COVERAGE THERAPY

Objectives:

The aim of this study was to evaluate the influence of the crown shape on the outcomes of root coverage procedures.

Material and methods:

Eighty patients with Miller class I gingival recessions in maxillary canines or premolars were selected. The recession areas were treated using the subepithelial connective tissue grafting. The following clinical parameters were analyzed: crown length (CL) and width (CW), recession height and width, probing depth, clinical attachment level, width and thickness of the keratinized tissue and percentage of root coverage achieved. These measurements were recorded at baseline and 6 months after the surgical procedure. The CW/CL ratio was calculated for each tooth and the median obtained (0.83). Patients were then ranked into two groups, according to the shape of the tooth with gingival recession: Group A – square crown shape (CW/CL values above 0.83) and Group B – long and narrow crown shape (CW/CL values below 0.83).

Results:

No statistically significant differences (p>0.05) were found between groups in any of the clinical parameters at baseline. After 6 months, both groups presented improved clinical outcomes for all parameters analyzed compared to baseline (p>0.05). The mean percentages and standard deviations of root coverage achieved in Group A and Group B was 91.37 (16.75) and 85.49 (23.55), respectively (p>0.05).

Conclusions:

Crown shape did not influence the root coverage obtained with the subepithelial connective tissue graft technique.     

Mucogingival interceptive surgery of buccally-erupted premolars in patients scheduled for orthodontic treatment. I. A 7-year longitudinal study

BACKGROUND: Mucogingival interceptive therapy in patients with buccally erupting teeth is performed to prevent the ectopic permanent tooth from developing periodontal lesions. The keratinized tissue entrapped between the erupting tooth and the deciduous tooth is retained to maintain a satisfactory width of the gingiva for the permanent tooth. The aim of the present study on buccally-erupted premolars scheduled for orthodontics was to evaluate the keratinized tissue width 3 months, 2 years, and 7 years subsequent to mucogingival interceptive therapy and orthodontic treatment. METHODS: Twenty-nine patients participated. Three different surgical techniques were used according to specific indications. Eight patients were treated with double pedicle flaps (DPF), 10 patients with apically positioned flaps (APF), and 11 with free gingival grafts (FGG). RESULTS: The amount of keratinized tissue on the treated (test) sites was not significantly less than on the control (untreated) sites showing normally erupting premolars at all observation periods. All 3 surgical procedures appeared to be effective in saving the keratinized tissue for the permanent tooth. Preoperative periodontal parameters such as gingival width, probing depth, and bleeding on probing significantly influenced the outcome 3 months after surgery (P <0.01). CONCLUSIONS: Mucogingival interceptive surgery is an effective approach to conserve the keratinized buccal gingiva of ectopically erupting premolars.     

Changes in the gingival thickness and keratinized gingival width of maxillary and mandibular anterior teeth after orthodontic treatment

ObjectivesTo evaluate changes in the gingival thickness (GT) and keratinized gingival width (KGW) of the maxillary and mandibular central and lateral incisors and canines after fixed orthodontic treatment and their association with sagittal tooth movement (STM).Materials and MethodsIn this study of both arches, 60 periodontally healthy subjects who had completed fixed orthodontic treatment were included. Using pretreatment and posttreatment lateral cephalograms, STM of the maxillary (1-NA angle and distance, and 1-SN angle) and mandibular (1-NB angle and distance, and IMPA angle) incisors were evaluated to divide the subjects into protrusion and retrusion groups. Pretreatment and posttreatment GT was identified via transgingival probing, and KGW was calculated from the free gingival margin to the mucogingival junction.ResultsThe intragroup pretreatment and posttreatment comparison results showed a significant decrease in the GT of the maxillary and mandibular anterior teeth in the protrusion and retrusion groups and a decrease in the KGW of the maxillary lateral incisors in the protrusion group. Pearson correlation coefficient analyses for maxillary and mandibular anterior teeth revealed that the GT changes were not significantly associated with STM. However, a positive correlation existed between the KGW of tooth numbers 13 and 41 and STM.ConclusionsSTM was not significantly associated with decreased GT of the maxillary and mandibular anterior teeth, but it was positively correlated with the KGW of tooth numbers 13 and 41.     

Anatomic crown width/length ratios of unworn and worn maxillary teeth in white subjects

STATEMENT OF PROBLEM: Dimensions of teeth have been available for a century. Some significant and clinically relevant aspects of dental esthetics, however, such as the crown width/length ratios, have not been presented in tooth morphology sources until recently. PURPOSE: The purpose of this study was to analyze the anatomic crowns of 4 tooth groups (central incisors, lateral incisors, canines, and first premolars) of the maxillary dentition with respect to width, length and width/length ratios and determine how these parameters are influenced by the incisal edge wear. MATERIAL AND METHODS: Standardized digital images of 146 extracted human maxillary anterior teeth from white subjects (44 central incisors, 41 lateral incisors, 38 canines, 23 first premolars) were used to measure the widest mesiodistal portion "W" (in millimeters) and the longest inciso-cervical/occluso-cervical distance "L" (in millimeters). The width/length ratio "R" (%) was calculated for each tooth. A 1-way analysis of variance was used to compare the mean values of W, L, and R for the different groups ("unworn" and "worn" subgroups, except for premolars). Multiple least significant difference range tests (confidence level 95%) were then applied to determine which means differed statistically from others. RESULTS: There was no influence of the incisal wear on the average value of W (width) within the same tooth group. The widest crowns were those of central incisors (9.10 to 9.24 mm) > canines (7.90 to 8.06 mm) > lateral incisors (7.07 to 7.38 mm). Premolars (7.84 mm) had similar width as canines and worn lateral incisors. The L-value was logically influenced by incisal wear (worn teeth were shorter than unworn teeth) except for lateral incisors. The longest crowns were those of unworn central incisors (11.69 mm) > unworn canines (10.83 mm) and worn central incisors (10.67 mm) > worn canines (9.90), worn and unworn lateral incisors (9.34 to 9.55 mm), and premolars (9.33 mm). Width/length ratios also showed significant differences. The highest values were found for worn central incisors (87%) and premolars (84%). The latter were also similar to worn canines (81%), which constituted a homogeneous group with worn lateral incisors (79%) and unworn central incisors (78%). The lowest ratios were found for unworn canines and unworn lateral incisors (both showing 73%). CONCLUSIONS: Along with other specific and objective parameters related to dental esthetics, average values for W (mesiodistal crown dimension), L (inciso-cervical crown dimension), and R (width/length ratio) given in this study for white subjects may serve as guidelines for treatment planning in restorative dentistry and periodontal surgery.     

Use of the apically repositioned flap in the management of labially impacted maxillary central incisors

Management of labially impacted maxillary central incisors often requires a coordinated surgical and orthodontic approach. In such cases, the treatment objective is surgical exposure of the unerupted incisor, preferably with a functional width of keratinized gingiva on the labial surface. Tooth exposure is then followed by orthodontic intervention to move the tooth to the line of occlusion. This paper describes three cases where the apically repositioned flap technique was used to manage labially impacted maxillary central incisors.     

根向复位瓣技术重建种植牙颊侧角化龈的临床探讨

目的 探讨在口腔种植修复中应用根向复位瓣技术重建颊侧角化龈的方法,评价其应用效果.方法 选择上颌后牙区单颗牙种植术后颊侧角化龈缺失或过窄的患者13例,在种植Ⅱ期手术时同期行根向复位瓣术进行角化龈重建,术后1个月取模行冠修复.测量并比较术前、冠修复后1个月、6个月、12个月术区转移角化组织的宽度及厚度,记录牙龈指数(gingival index,GI)和龈沟探诊出血(bleeding on probing,BOP)情况.结果 冠修复后1、6、12个月,转移组织角化特征明显,组织健康,质地色泽与邻牙一致.3次测量宽度均值分别(3.25±0.40)mm、(3.04±0.34)mm、(2.97±0.32)mm;厚度均值分别为(2.05±0.20)mm、(1.91±0.23)mm、(1.84±0.25)mm;与邻牙角化龈的宽度(3.19±0.42)mm和厚度(1.96±0.23)mm的差异无统计学意义(P>0.05).GI和BOP阳性率与邻牙接近,呈健康牙龈形态.结论 在种植Ⅱ期手术时同期采用根向复位瓣技术能有效重建种植体周围的附着龈,效果可靠.     

Some periodontal tissue reactions to orthodontic tooth movement in monkeys

The purpose of the experiment reported was to study soft tissue changes at teeth which were orthodontically moved into areas with varying thickness and quality of periodontal tissues. The maxillary central incisors and first premolars in 5 adult monkeys were used as experimental teeth. 6 months prior to the start of the orthodontic treatment phase, the maxillary second premolars were extracted. By surgical means, areas with varying width of the keratinized gingiva were established in the incisor and premolar region. Following a clinical baseline examination which involved assessments of gingival width, location of the gingival margin in relation to cemento-enamel junction and probing attachment level, fixed orthodontic appliances were inserted in order to bodily move the two contral incisors in labial direction through the alveolar bone envelope and the first premolars in distal direction into contact with the first molars. Orthodontic forces were applied for a period of 3-4 months. The lateral incisors and first molars were selected as non-moved control teeth. After the experimental teeth had been retained in their new positions for 1 month, the clinical examination was repeated. Tissue blocks containing test and control specimens were subsequently dissected and prepared for microscopic analysis. The analysis included histometric assessments of loss of connective tissue attachment and height of alveolar bone. The results showed that at every second labially moved incisor, the gingival margin had become displaced in apical direction. The degree of displacement, however, was small and only at 2 teeth accompanied by loss of connective tissue attachment. Throughout the study, these particular teeth also showed obvious signs of gingival inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Gingival condition in areas of minimal and appreciable width of keratinized gingival

Sixteen dental, dental hygiene, and dental assisting students and dental faculty members who had contralateral or unilateral areas of minimal (less than or equal to 1.0 mm) and appreciable (greater than or equal to 2.0 mm) widths of keratinized gingiva on mid-buccal plaque-free surfaces of mandibular bicuspids were examined. Gingival exudate amounts and clinical inflammation based on color change and/or swelling and bleeding on probing were evaluated. The results showed that gingiva with "appreciable" width as well as gingiva with "minimal" width of keratinized tissue exhibited only minute amounts of gingival exudate. Also, there were generally no clinical signs of inflammation for both types of tissue. From the groups of 16, six subjects were selected who had contralateral pairs of minimal and appreciable keratinized gingiva. They were instructed to cease oral hygiene in the lower bicuspid area for 25 days. At day 0, 4, 7, 11, 14, 18, 21, and 25, plaque, gingival exudate, and clinical gingival inflammation were evaluated. Results revealed increases in plaque, gingival exudate scores and clinical gingival inflammation over the 25-day period with no apparent difference between the areas with minimal and appreciable width of keratinized gingiva.