Digital analysis of the correlation between gingival thickness and alveolar bone thickness in the maxillary anterior teeth region / 中华口腔医学杂志

Objective: To measure the labial gingival thickness and bone lamella thickness in the maxillary anterior area using digital method, and to analyze the correlation between the two, so as to provide a reference for esthetic restoration and implantation treatment of the upper anterior area. Methods: Fifty-seven patients [23 males, 34 females, (25.8±4.5) years old] who planned to receive posterior dental implant restoration were recruited randomly with the inclusion and exclusion criteria in Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University from May 2020 to October 2020. The 3Shape software was used to perform oral scanning, and cone beam CT (CBCT) was taken for each patient. The image data was fitted and registered by the 3Shape software. The gingival thickness at 2 mm below the gingival margin, bone thickness and gingival thickness at 2 and, 4 mm below the crest of the labial alveolar crest in maxillary central incisors, lateral incisors and canines, were measured. Results: The gingival thickness at 2 mm below the gingival margin of maxillary central incisors, lateral incisors and canines was (1.42±0.21), (1.19±0.17) and (1.23±0.20) mm respectively (F=12.47, P<0.001). The gingival thickness at 2 mm below gingival margin and 4 mm below crest of residual ridge in the male patients were (1.31±0.21) and (0.67±0.22) mm, and those in the female patients were (1.26±0.22) and (0.58±0.19) mm respectively, and there were statistically significant differences in the gingival thickness between the "2 mm below gingival margin" group and the "4 mm below crest of residual ridge" group (t=2.01 and 3.97, P<0.05). There was a positive correlation between gingival thickness and alveolar bone thickness at 2 mm and 4 mm below the crest of residual ridge in maxillary anterior region, and the correlation coefficients (r) were 0.387 and 0.344 respectively (P<0.05). Conclusions: Gingival thickness of maxillary anterior area is related to the tooth position and gender. The gingival thickness of men is greater than that of women.The gingival thickness at 2 and 4 mm below the crest of the alveolar crest is positively correlated with the thickness of the alveolar bone.

Three-dimensional morphology analysis of the supraosseous gingival profile of periodontally healthy maxillary anterior teeth / 北京大学学报(医学版)

OBJECTIVE@#To measure the three-dimensional morphology of the labial supraosseous gingiva (SOG) and the thickness of related labial bone in maxillary anterior teeth of periodontally healthy Han nationality youth using soft tissue indirect imaging cone-beam computed tomography (CBCT).@*METHODS@#Twenty-five periodontally healthy subjects (11 males and 14 females) with 150 maxillary anterior teeth were involved in this study. A special impression with radiopaque material including the maxillary teeth was made, then a CBCT scan with the elastomeric matrix in position was taken for each subject. The imaging data were generated and transferred to a volumetric imaging software in which three-dimensional reconstruction was conducted and the image analyses were carried out. Measurements were made at the site of labial center of the maxillary anterior teeth. The height of the SOG, the distance between cemento-enamel junction (CEJ) and bone crest, the gingival thickness at the CEJ, and the thickness of bone 2 mm below the labial bone crest were measured and the correlation analysis between the parameters was made. All the data analyses were performed using SPSS 22.0. The data were analyzed with ANVOA and Pearson correlation tests with the significance level at α=0.05.@*RESULTS@#The mean SOG values were (3.49±0.70) mm, (3.48±0.81) mm, and (3.54±0.67) mm for central incisors, lateral incisors and canines, respectively. There were no statistically significant differences among the different sites (P > 0.05). The mean gingival thickness values were (1.45±0.23) mm, (1.13±0.24) mm, (1.14±0.22) mm for central incisors, lateral incisors and canines, respectively. The gingival thickness of the central incisors was the largest among the maxillary anterior teeth with statistically significant difference (P < 0.05). No correlation was found between the SOG and gingival thickness among the maxillary anterior teeth (P > 0.05).@*CONCLUSION@#The gingival thickness of central incisors was the largest and the supraosseous gingival height had no correlation with gingival thickness among the periodontally healthy maxillary anterior teeth.

Uso de métodos não invasivos para avaliação da espessura muco-gengival: a tecnologia a favor do diagnóstico / Use of non-invasive methods to evaluate muco-gingival thickness: the technology in favor of diagnosis

O objetivo no presente estudo foi realizar uma revisão atualizada da literatura sobre os diferentes métodos não invasivos utilizados para avaliação da espessura muco-gengival. O biotipo gengival é considerado um dos principais elementos de influência no resultado do tratamento estético. Pacientes com gengiva espessa demonstram ser mais resistentes à recessão gengival após terapia cirúrgica e/ou restauradora. Em contrapartida, pacientes com biotipo fino apresentam maior risco de recessão, sendo necessário, muitas vezes, o enxerto de tecido conjuntivo. O palato é a principal área doadora para enxerto de tecido conjuntivo subepitelial, sendo que a determinação da espessura da mucosa palatina é de grande importância para a previsibilidade dos procedimentos cirúrgicos. Existem diversos métodos para mensurar a espessura muco-gengival, alguns considerados invasivos, como: a avaliação transgengival (ou transmucosa); e outros, mais recentes, considerados não invasivos, como as imagens seccionais de ultrassom, tomografias computadorizadas ou imagens de ressonância magnética. Apesar de diversos estudos demonstrarem resultados positivos do uso de exames por imagens para avaliação da espessura dos tecidos muco-gengivais, concluiu-se que os métodos invasivos ainda parecem ser os mais utilizados.

The aim of the present study was to carry out an updated review of the literature on the different non-invasive methods used to evaluate muco-gingival thickness. The gingival biotype is considered one of the main influential elements in the result of the aesthetic treatment. Patients with thick gingiva demonstrate to be more resistant to gingival recession after surgical and/or restorative therapy. On the other hand, patients with fine biotype are at greater risk of recession, often requiring the grafting of connective tissue. The palate is the main donor area for subepithelial connective tissue graft, and the determination of the thickness of the palatal mucosa is of great importance for the predictability of surgical procedures. There are several methods to measure muco-gingival thickness, some considered invasive, such as: transgingival (or transmucosal) evaluation; and others, more recent, considered noninvasive, such as sectional images of ultrasound, computed tomography or magnetic resonance imaging. Although several studies show the positive results of the use of images in the assessment of thickness of mucogingival tissues, invasive methods still appear to be the most used.

Do different vertical positions of maxillary central incisors influence smile esthetics perception?

ABSTRACT INTRODUCTION: The purpose of this study was to determine the perception of smile esthetics among orthodontists and layperson, with respect to different maxillary central incisors vertical positions in full-face and close-up smile analyses. METHODS: Frontal photographs of the smiles of two adult women were used. Images were altered to create a symmetrical image with the gingival margin levels of the maxillary canines matching the central incisors and a 1.0-mm central-to-lateral incisal step. Later, the images were altered in order to create six different central incisor vertical positions in 0.5-mm increments. The images were randomly assembled in an album, which was given to 114 judges, 57 orthodontists and 57 laypersons, who were asked to evaluate the attractiveness of the images using the visual analog scale. The data collected were statistically analyzed by means of 1-way analysis of variance with the Tukey post-hoc test and the Student t test. RESULTS: The highest rated smiles showed two notable characteristics: a) the central incisor gingival margins matched or were 0.5 mm below the line of the canine gingival margins and; b) the central-to-lateral incisal step was 1.0 to 1.5 mm. The worst smiles showed two notable characteristics: a) the central incisor gingival margins were 1.0 mm above or 1.5 mm below the canine gingival margins and; b) no step between the centrals and laterals or a 2.5-mm step. CONCLUSION: The vertical position of the maxillary central incisors significantly affected the perception of the smile esthetics, whereas slightly extruded central incisors were more esthetically preferred than intruded.

RESUMO OBJETIVO: o objetivo do presente estudo foi avaliar a percepção da estética do sorriso, entre ortodontistas e leigos, em relação a diferentes posições verticais de incisivos centrais superiores, em análises de face completa e do sorriso aproximado. MÉTODOS: foram utilizadas fotografias frontais de sorrisos de duas mulheres adultas. As imagens foram alteradas para criar uma imagem simétrica, com o nível das margens gengivais dos caninos superiores igual ao dos incisivos centrais e um degrau incisal de 1,0 mm entre central e lateral. Posteriormente, as imagens foram alteradas para criar seis diferentes posições verticais de incisivos centrais, em incrementos de 0,5 mm. As imagens foram montadas aleatoriamente em um álbum, que foi dado a 114 avaliadores (57 ortodontistas e 57 leigos), que foram convidados a avaliar a atratividade das imagens usando uma escala analógica visual. Os dados coletados foram analisados estatisticamente por meio da análise de variância (ANOVA) de um fator com o teste post-hoc de Tukey e o teste t de Student. RESULTADOS: os sorrisos mais bem avaliados apresentaram duas características notáveis: a) as margens gengivais dos incisivos centrais corresponderam ou estavam 0,5 mm abaixo da linha das margens gengivais dos caninos; b) o degrau incisal entre central e lateral foi de 1,0 a 1,5 mm. Os piores sorrisos mostraram duas características notáveis: a) as margens gengivais dos incisivos centrais estavam 1,0 mm acima ou 1,5 mm abaixo das margens gengivais dos caninos e; b) nenhum degrau entre os centrais e laterais ou um degrau de 2,5 mm. CONCLUSÃO: a posição vertical dos incisivos centrais superiores afetou significativamente a percepção da estética do sorriso, ao passo que incisivos centrais ligeiramente extruídos foram mais preferidos esteticamente do que intruídos.

Improving gingival smile by means of guided bone regeneration principles

ABSTRACT Objective: This study evaluated the effectiveness of guided bone regeneration (GBR) carried out with xenogenic bone substitute (Bio-OssTM) and collagen resorbable membrane (Bio-GideTM) to improve gingival smile (GS) in patients with excessive vertical maxillary growth (EVMG). Methods: Twelve healthy women aged between 20 and 49 years old (mean age of 26 years), with 5 mm or more of gingival exposure during fully posed smile (FPS) due to EVMG, were included. Baseline digital photographs were taken with standardized head position at rest and FPS. In eight out of 12 cases, crown lengthening procedure was indicated and the initial incision was made 2 to 4 mm from the gingival margin. In four cases, with no indication for crown lengthening procedure, a sulcular incision was performed. GBR was performed in all cases, using micro screws and/or titanium mesh associated with Bio-OssTM and Bio-GideTM. After 10 days, sutures were removed. Recall appointments were scheduled at 1, 6, and 12 months when standardized photographs were again taken. ImageToolTM software was used to measure the gingival exposure (GE) during FPS from the standardized close-up smile photographs at baseline and 12 months. Results: GE mean at baseline was 275.44 mm2. After 12 months, patients who undergone exclusively GBR procedure, presented GE reduction of 40.7%, ∆ = 112.01 mm2 (statistically significant, p = 0.12), and patients who had crown lengthening associated with the graft had a reduction of 60%, ∆ = 167.01 mm2. Conclusion: Our results using GBR to improve GS in cases of EVMG showed an exceptionally high patient acceptance and satisfaction. One-year follow-up confirmed stable results.

RESUMO Objetivo: o presente estudo avaliou a eficácia da regeneração óssea guiada (ROG) usando enxerto ósseo xenógeno (Bio-Oss(r)) e membrana de colágeno reabsorvível (Bio-Gide(r)) para melhorar a estética do "sorriso gengival" (SG) em pacientes com crescimento maxilar vertical excessivo (CMVE). Métodos: foram incluídas 12 mulheres saudáveis com idades entre 20 e 49 anos (média = 26 anos) com 5mm ou mais de exposição gengival durante o sorriso amplo posado (SAP), em função de CMVE. Foram realizadas fotografias digitais padronizadas (FDP) em repouso e em SAP. Em 8 dos 12 casos, foi indicado o procedimento de aumento da coroa clínica, e a incisão inicial foi realizada de 2 a 4mm da margem gengival. Em 4 casos, para os quais não houve indicação de aumento da coroa clínica, foi realizada uma incisão intrassulcular. A ROG foi realizada, em todos os casos, utilizando-se mini-implantes e/ou malha de titânio, associados a Bio-Oss(r) e Bio-Gide(r). Após 10 dias, as suturas foram removidas. O programa ImageTool(r) foi utilizado para medir a "área gengival exposta" (AGE) durante o SAP, nas imagens padronizadas do sorriso, em close-up, ao início do estudo e após 12 meses. Resultados: a média da AGE no início do estudo foi de 275,44mm2. Após 12 meses, os pacientes submetidos exclusivamente ao procedimento de ROG apresentaram redução na AGE de 40,7%, Δ = 112,01mm2 (estatisticamente significativo, p = 0,12); já nos pacientes em que o aumento de coroa clínica foi associado ao enxerto, a redução foi de 60%, Δ = 167,01mm2. Conclusão: os resultados do uso da ROG para melhorar o SG em casos de CMVE demonstraram aceitação e satisfação extremamente elevadas por parte dos pacientes. O acompanhamento de 1 ano pós-tratamento confirmou a estabilidade dos resultados.

Changes in alveolar bone support induced by the Herbst appliance: a tomographic evaluation

ABSTRACT Objective: This study evaluated alveolar bone loss around mandibular incisors, induced by the Herbst appliance. Methods: The sample consisted of 23 patients (11 men, 12 women; mean age of 15.76 ± 1.75 years), Class II, Division 1 malocclusion, treated with the Herbst appliance. CBCT scans were obtained before treatment (T0) and after Herbst treatment (T1). Vertical alveolar bone level and alveolar bone thickness of mandibular incisors were assessed. Buccal (B), lingual (L) and total (T) bone thicknesses were assessed at crestal (1), midroot (2) and apical (3) levels of mandibular incisors. Student's t-test and Wilcoxon t-test were used to compare dependent samples in parametric and nonparametric cases, respectively. Pearson's and Spearman's rank correlation analyses were performed to determine the relationship of changes in alveolar bone thickness. Results were considered at a significance level of 5%. Results: Mandibular incisors showed no statistical significance for vertical alveolar bone level. Alveolar bone thickness of mandibular incisors significantly reduced after treatment at B1, B2, B3, T1 and significantly increased at L2. The magnitude of the statistically significant changes was less than 0.2 mm. The changes in alveolar bone thickness showed no statistical significance with incisor inclination degree. Conclusions: CBCT scans showed an association between the Herbst appliance and alveolar bone loss on the buccal surface of mandibular incisors; however, without clinical significance.

RESUMO Introdução: este estudo avaliou a perda óssea alveolar ao redor dos incisivos inferiores induzida pelo aparelho de Herbst. Métodos: a amostra foi composta por 23 pacientes (11 homens e 12 mulheres; média de idade 15,76 ± 1,75 anos), má oclusão de Classe II, divisão 1, tratados com aparelho de Herbst. TCFCs foram realizadas antes do tratamento (T0) e após o tratamento (T1) com o Herbst. A altura e a espessura óssea alveolar dos incisivos inferiores foram avaliadas. As espessuras ósseas vestibular (V), lingual (L) e total (T) foram mensuradas nos terços cervical (1), médio (2) e apical (3) dos incisivos inferiores. O teste t de Student e o teste t de Wilcoxon compararam as amostras dependentes nos casos paramétricos e não paramétricos, respectivamente. As análises de Pearson e Spearman determinaram a correlação entre as alterações na espessura do osso alveolar. Os resultados foram considerados para um nível de significância de 5%. Resultados: os incisivos inferiores não apresentaram significância estatística para a altura óssea alveolar. Após o tratamento, a espessura óssea alveolar dos incisivos inferiores reduziu-se significativamente em V1, V2, V3 e T1 e aumentou significativamente em L2. A quantidade da alteração óssea significativa foi menor que 0,2mm. As alterações na espessura óssea alveolar não apresentam correlação estatisticamente significativa com o grau de inclinação do incisivo. Conclusões: as imagens de TCFC demonstram associação entre o uso do aparelho de Herbst e a perda óssea alveolar no lado vestibular dos incisivos inferiores; entretanto, sem significância clínica.

Non invasive and surgical measurement of length of soft tissue from the tip of interdental papilla to the alveolar crest

Various methods, including clinical and radiographic techniques, can be used to assess periodontal regeneration in interproximal areas. The goal of the present study was Periodontal regeneration; to compare the papilla length relative to the alveolar bone crest measured by clinical, intrasurgical, Radiographic bone length; and radiographic techniques. Bone probing length; Materials and The study sample included 250 interproximal papillae in 68 patients with Actual papilla length generalized chronic periodontitis. The papilla length from the alveolar bone crest was measured clinically [as the actual papilla length, APL], intrasurgically [as the bone probing length, BPL], and radiographically [as the radiographic bone length, RBL]. Measurements were standardized by using acrylic resin stents, XCP rinn, a paralleling technique, and/or a radiographic grid. The mean [+/- standard deviation] for RBL was 4.9 +/- 0.8 mm, BPL was 5.1 +/- 0.6 mm, and APL was 5.1 +- 0.6 mm. Correlations between RBL and APL and between BPL and APL were 0.918 and 0.943, respectively [both P < 0.01]. If the clinical recordings are appropriately standardized, then noninvasive radio-graphic methods can be used to evaluate the papilla length with good accuracy

Evaluation of an innovative radiographic technique - parallel profile radiography - to determine the dimensions of dentogingival unit.

Background: Maintenance of gingival health is a key factor for longevity of the teeth as well as of restorations. The physiologic dentogingival unit (DGU), which is composed of the epithelial and connective tissue attachments of the gingiva, functions as a barrier against microbial entry into the periodontium. Invasion of this space triggers inflammation and causes periodontal destruction. Despite the clinical relevance of the determination of the length and width of the DGU, there is no standardized technique. The length of the DGU can be either determined by histologic preparations or by transgingival probing. Although width can also be assessed by transgingival probing or with an ultrasound device, they are either invasive or expensive Aims: This study sought to evaluate an innovative radiographic exploration technique - parallel profile radiography - for measuring the dimensions of the DGU on the labial surfaces of anterior teeth. Materials and Methods: Two radiographs were made using the long-cone parallel technique in ten individuals, one in frontal projection, while the second radiograph was a parallel profile radiograph obtained from a lateral position. The length and width of the DGU was measured using computer software. Transgingival probing (trans-sulcular) was done for these same patients and length of the DGU was measured. The values obtained by the two methods were compared. Pearson product correlation coefficient was calculated to examine the agreement between the values obtained by PPRx and transgingival probing. Results: The mean biologic width by the parallel profile radiography (PPRx) technique was 1.72 mm (range 0.94-2.11 mm), while the mean thickness of the gingiva was 1.38 mm (range 0.92-1.77 mm). The mean biologic width by trans-gingival probing was 1.6 mm (range 0.8-2.2mm). Pearson product correlation coefficient (r) for the above values was 0.914; thus, a high degree of agreement exists between the PPRx and TGP techniques. Conclusions: We conclude that the biologic width of the DGU in humans can be measured with the PPRx technique. The values obtained agree with the values obtained by transgingival probing, a technique considered standard so far. Thus, the PPRx technique offers a simple, concise, noninvasive, and reproducible method that can be used in the clinical setup to measure both the length and thickness of the DGU with accuracy.

Histopathologic changes in soft tissue associated with radiographically normal impacted third molars.

Background: The incidence of impacted or embedded third molars accounts for approximately 98%. Since 1948, there are studies reporting pathological changes in an asymptomatic dental follicle. Controversy still exists for removal of asmptomatic impacted teeth. Hence, this study was performed to histologically evaluate soft tissue pathosis in the pericoronal tissues of impacted third molars with pericoronal radiolucency measuring up to 2.5 mm on orthopantomographs. Materials and Methods: Forty-one asymptomatic impacted third molars with follicular space of up to 2.5 mm on radiographs were included. The disimpacted teeth and the follicular tissues were obtained for histological examination. Results: Age of the patients ranged from 14 to 25 years. Of 41 tissues evaluated, histopathological reports of 18 follicles were suggestive of dentigerous cyst, two follicles showed odontogenic keratocyst, one follicle each of calcifying epithelial odontogenic cyst, ameloblastoma-like proliferation, odontogenic myxoma and odontogenic fibroma. Conclusion: This study showed 58.5% of asymptomatic cases with definite pathological changes. Hence, thorough clinical and radiographic examination should be carried out for all impacted third molars and the dental follicular tissue should be submitted for histopathological evaluation.