CBCT analysis of the relative position between maxillary central incisors and alveolar bone in Southern Chinese adults / 口腔疾病防治

Objective@#Exploring the position and bone wall thickness characteristics of the maxillary central incisors in Southern Chinese adults to provide a clinical reference for the design of immediate maxillary central incisor implantation surgery.@*Methods@#The hospital ethics committee approved the study, and the patients provided informed consent. CBCT images of 990 adult patients (aged 20-79 years) from the Stomatology Hospital (January 2018 to December 2021) were categorized based on the dental arch form and age-sex groups. Sagittal CBCT images of the maxillary central incisors were used to measure the labial and palatal bone thickness wall at 4 mm the CEJ to apical, the middle of the root, and the angle between the tooth long axis and the long axis of the alveolar process, to compare the thickness of the labial and palatal bone walls in samples of male and female patients, and to explore the relationship between the angle between the tooth long axis and the alveolar process long axis in samples of male and female patients in different age groups (20-39 years; 40-59 years; 60-79 years).@*Results@#Significant differences were found in the labiopalatine side of the alveolar bone of the maxillary incisor root position. A total of 95.8% (948/990) of the maxillary incisors were positioned more buccally, 4.1% (41/990) were positioned more midway, and 0.1% (1/990) were positioned more palatally. The thicknesses of the bone wall at the CEJ of 4 mm below the palatal side, the middle of the root, and at the apex were greater (1.82 ± 0.56 mm, 3.20 ± 1.10 mm, and 7.70 ± 2.00 mm, respectively) than those at the labial side (1.21 ± 0.32 mm, 0.89 ± 0.35 mm, and 1.86 ± 0.82 mm, respectively), with statistical significance (P<0.05). Male bone wall thickness was generally greater than female bone wall thickness (P<0.05). The angle between the long axis of male teeth and the alveolar bone was 14.77° ± 5.66°, while that of female teeth was 12.80° ± 5.70°, with a statistically significant difference (P<0.05). The angle between the long axis of teeth and the alveolar bone in the 40-59-year-old group and the 60-79-year-old group was greater than that in the 20-39-year-old group, and the difference was statistically significant (P<0.05).@*Conclusion@#A total of 95.8% of adults in South China have maxillary central incisors with root deviation toward the labial bone cortex. The thickness of the labial bone wall is much thinner than that of the labial bone wall, which is the middle of the thickness of the root. In Southern Chinese adults, the angle between the upper central incisor and the long axis of the alveolar bone in males is greater than that in females, and the degree of the angle increases with age. It is recommended to pay attention to the thickness of the bone wall around the root and the angle between the teeth before immediate implantation surgery to choose a reasonable implantation plan.

Aesthetic perception of black spaces between lower incisors by laypeople of different ethnicities and age groups

Objective: To evaluate the degree of perception among lay people of different age groups about black spaces between lower incisors. Methodology: digital changes were performed in a frontal photograph of a smiling 30 year-old patient, simulating different dimensions of black spaces. The images were printed on photographic paper and applied with a questionnaire in order to evaluate the attractiveness using as tool a visual analogue scale (VAS). The participants were divided into 6 groups, considering race (Caucasian and Negroid) and age (15-19 years, 35-44 years and 65-74 years old). The differences between the examiners were checked by the Mann-Whitney test and the significance level was 5% (α = 0.05) for all analyzes. Results: The photographs that did not have black spaces were better graded and the ones that had larger black spaces scored worse. The older age group and the Negroid race group graded better the photograph with the largest black spaces, compared to the younger age groups and the group of Caucasians. Conclusion: black spaces between lower incisors are esthetically unattractive and their perception decreases with aging, besides being less relevant to older and Negroid people.

Evaluation of enamel thickness of mandibular incisors

ABSTRACT Objective: To measure enamel thickness at the proximal surfaces of the mandibular incisors, using micro-computed tomography (micro-CT) scans. Material and Methods: Forty-one single-rooted mandibular incisors were selected and analyzed according to anatomical characteristics, to form three groups: Group 1 - central incisors (n = 18); Group 2 - right lateral incisors (n = 10); and Group 3 - left lateral incisors (n = 13). First, enamel thickness at the proximal contact areas of the mandibular incisors was measured. Second, the mesial and distal surfaces of the lateral incisors were compared. Finally, the relationship between the tooth width and the mean enamel thickness was determined. Each tooth was scanned with a micro-CT scanner, and the image was processed with SCANCO micro-CT onboard analysis software. Results: There were no statistically significant differences in mean enamel thickness between the mesial and distal surfaces for each lateral incisor, or between contralateral lateral incisors. In all surfaces analyzed, the upper zones had statistically significantly thinner enamel (0.52 ± 0.10 mm) when compared to the middle and lower zones (0.60 ± 0.08 mm and 0.59 ± 0.08 mm, respectively). There was no correlation (r =0.07) between enamel thickness of the mandibular incisor and the tooth width. Conclusions: The enamel thickness of the mandibular incisors is similar on the mesial and distal surfaces, with the thinnest layer located at the upper zone.

RESUMO Objetivo: Medir a espessura do esmalte nas superfícies proximais dos incisivos inferiores, usando imagens de microtomografia computadorizada (micro-CT). Material e Métodos: Quarenta e um incisivos inferiores com raiz única foram selecionados e analisados de acordo com as características anatômicas, formando três grupos: Grupo 1 - incisivos centrais (n = 18); Grupo 2 - incisivos laterais direitos (n = 10); e Grupo 3 - incisivos laterais esquerdos (n = 13). Primeiro, foi medida a espessura do esmalte nas áreas de contato proximal dos incisivos inferiores. Em segundo lugar, as faces mesial e distal dos incisivos laterais foram comparadas. Por fim, foi determinada a relação entre a largura do dente e a espessura média do esmalte. Cada dente foi escaneado com um scanner micro-CT, e a imagem foi processada com o software de análise SCANCO micro-CT. Resultados: Não houve diferenças estatisticamente significativas na espessura média do esmalte entre as superfícies mesial e distal de cada incisivo lateral, ou entre os incisivos laterais contralaterais. Em todas as superfícies analisadas, as zonas superiores apresentaram esmalte significativamente mais fino (0,52 ± 0,10 mm) quando comparadas às zonas média e inferior (0,60 ± 0,08 mm e 0,59 ± 0,08 mm, respectivamente). Não houve correlação (r = 0,07) entre a espessura do esmalte do incisivo inferior e a largura do dente. Conclusões: A espessura do esmalte dos incisivos inferiores é semelhante nas faces mesial e distal, com a camada mais fina localizada na zona superior.

Management of unerupted anterior teeth an audit of treatment outcomes

Anterior teeth are valuable for aesthetics, speech and mastication . Their absence, impaction and/or delayed eruption create significant distress often leading to early presentation to the dental office. This study presents an audit of the management of impacted anterior teeth that presented at a tertiary level dental clinic. The periodontal outcomes of the aligned teeth were also reported. Methods : This is an observational study spanning a nine-year period. Demographic data, clinical presentation as well as post alignment dental and periodontal status of the impacted teeth were assessed. Data was analysed using the Statistical Package for Social Sciences (SPSS) version 26. Fisher's exact test and paired samples T-test were used for categorical and continuous variables respectively. Significance was set at P < 0.05. Results: Twenty-eight (1.76%) cases presenting with failed eruption of thirty-two anterior teeth were found during the period under review. Eight patients were treated by extraction, orthodontic treatment and space closure or prosthetic replacement with a mean treatment time of 2.83 ± 2.66 years. Thirteen patients completed treatment by orthodontic alignment with mean alignment time of 1.4 ± 1.5 years and treatment time of 3.6 ± 2.5 years. There was significant difference in the post-operative root length of aligned teeth compared to their normal antimeres (p < 0.005). Conclusion: Patients with impacted anterior teeth presented later than was beneficial for spontaneous alignment of their teeth. The average 1.5mm loss of root length observed was not detrimental to the anatomical retention or function of the aligned teeth. There is need for more enlightenment with regards to early presentation for dental problems to avoid expensive and time-consuming treatments.

Inter-incisive index in Bulgarians and its application in dentistry / Indice interincisivo en búlgaros y su aplicación en odontología

SUMMARY: In recent years, aesthetic dentistry has become a major focus for the public. Facial attractiveness plays a key role on modern society and the creation of harmonious smile is an aim for every dentist. The objective of this study was to define certain values of the inter-incisive index in Bulgarians, the sexual dimorphism and bilateral asymmetry and to verify differences of this index between Bulgarians and other Balkan populations. The present study included 121 males and 111 females of Bulgarian origin aged 20- 40 years. Mesiodistal dimensions of maxillary central and lateral incisors were measured by Dentistry Sliding Vernier Caliper. We used the technique of direct anthropometry, modified by Prof. Y. Yordanov. We calculated the inter-incisive index as ratio of the mesiodistal dimension of maxillary lateral incisor to the mesiodistal dimension of the maxillary central incisor. The measurements were analyzed with SPSS 23. The level of statistical significance was set at P< 0.05. The inter-incisive index showed no statistically significant differences between left and right side of the dental arch in both sexes. We did not find statistically significant differences between males and females as well. On the other hand, we found statistically significant differences in MD values of incisors between Bulgarians and other Balkan nations. Inter-incisive index shows no sexual dimorphism and bilateral asymmetry in Bulgarians. This can be helpful in aesthetic dentistry, in prosthodontics and in orthodontic treatment planning.

RESUMEN: En los últimos años, la odontología estética se ha convertido en un foco importante para el público. El atractivo facial juega un papel clave en la sociedad moderna y la creación de una sonrisa armoniosa es importante para todos los dentistas. El objetivo de este estudio fue definir ciertos valores del índice interincisivo en búlgaros, el dimorfismo sexual y la asimetría bilateral y verificar diferencias de este índice entre búlgaros y otras poblaciones balcánicas. El presente estudio incluyó a 121 hombres y 111 mujeres de origen búlgaro entre 20 y 40 años de edad. Las dimensiones mesiodistales de los incisivos superiores centrales y laterales se midieron con un calibrador Vernier deslizante de odontología. Utilizamos la técnica de antropometría directa, modificada por el Prof. Y. Yordanov y se calculó el índice interincisivo como la relación entre la dimensión mesiodistal del incisivo lateral superior y la dimensión mesiodistal del incisivo central superior. Las medidas se analizaron con SPSS 23. El nivel de significancia estadística se fijó en P<0,05. El índice interincisivo no mostró diferencias estadísticamente significativas entre los lados izquierdo y derecho de la arcada dentaria en ambos sexos. Tampoco encontramos diferencias estadísticamente significativas entre hombres y mujeres. Por otro lado, encontramos diferencias estadísticamente significativas en los valores de DM de los incisivos entre búlgaros y otras naciones balcánicas. El índice interincisivo no muestra dimorfismo sexual ni asimetría bilateral en los búlgaros. Esto puede ser útil en odontología estética, en prostodoncia y en la planificación de tratamientos de ortodoncia.

Agenesis of maxillary lateral incisors: diagnosis and treatment options

ABSTRACT Introduction: There are different possibilities of orthodontic planning for cases with congenital absence of maxillary lateral incisors. This subject divides the opinion of orthodontists and oral rehabilitation clinicians, due to the advantages and disadvantages of each treatment option, which may involve opening spaces for future implants and/or prosthetic restorations, or closing the spaces by positioning the maxillary canines in the place of lateral incisors. The correct diagnosis and careful evaluation of each patient allow to determine the best therapeutic approach. This paper discusses the main topics to be considered when planning these cases. Objectives: To evaluate the main aspects related to orthodontic treatment planning in cases of congenital absence of maxillary lateral incisors, to aid the decision-making, with clinical and scientific basis.

RESUMO Introdução: Existem diferentes possibilidades de planejamento ortodôntico para os casos que apresentam ausência congênita de incisivos laterais superiores. Esse é um assunto que divide a opinião de ortodontistas e reabilitadores orais, devido às vantagens e desvantagens de cada uma das opções de tratamento, as quais podem envolver a abertura de espaços para futuros implantes e/ou restaurações protéticas ou o fechamento dos espaços, com posicionamento dos caninos superiores no lugar dos incisivos laterais. O correto diagnóstico e uma criteriosa avaliação de cada paciente permitem determinar a melhor abordagem terapêutica. Nesse artigo, serão discutidos os principais tópicos a serem considerados no planejamento desses casos. Objetivos: Avaliar os principais aspectos relacionados ao planejamento do tratamento ortodôntico nos casos de ausência congênita de incisivos laterais superiores, de maneira a auxiliar nas tomadas de decisão, com embasamento clínico e científico.

Ausencia congénita de incisivos laterales superiores. Enfoques terapéuticos y sus resultados a largo plazo. Revisión descriptiva

RESUMEN: La agenesia de incisivos laterales superiores corresponde a un desafío clínico, en cuanto a planificación de tratamiento, así como también para la obtención de resultados estéticos y funcionales adecuados. Con el fin de conseguirlo, el clínico debería informarse sobre las diferentes opciones terapéuticas disponibles en la actualidad, considerando que la indicación depende de cada caso clínico individual, es decir, del paciente en su contexto integral sumado a su condición intra-oral. Además, es importante evaluar los resultados a largo plazo de las diferentes alternativas, para lograr la resolución clínica más adecuada y estable en el tiempo. El éxito en estos pacientes, requiere de un enfoque multidisciplinario, considerando especialistas en ortodoncia, rehabilitación oral, periodoncia y cirugía oral de ser necesario. El objetivo de esta revisión es describir y comparar las alternativas terapéuticas para la agenesia de incisivos laterales maxilares.

ABSTRACT: The agenesis of upper lateral incisors represents a clinical challenge regarding treatment planning and appropriate aesthetic and functional results. In order to obtain the best results, the clinician should be informed about the different therapeutic options currently available, considering that the indication depends on each individual clinical case, that is, on the patient in his/her comprehensive context in addition to his/her oral condition. It is also important to evaluate long term results from each treatment available, in order to achieve the better outcome and most importantly, a stable clinical resolution over time. The treatment success in this kind of patients requires a multidisciplinary approach, including specialists in orthodontics, oral rehabilitation, periodontics, and oral surgery if necessary. The objective of this review is to describe and compare the therapeutic alternatives for maxillary lateral incisor agenesis.

Central incisors shape and proportions prevalence in Argentinian university students / Prevalencia de forma y tamaño de los incisivos centrales en estudiantes universitarios argentinos

ABSTRACT The aim of this study was to analyze the dimensions of the clinical crown of upper central incisors and the prevalence of tooth shapes by two different protocols. Assessment was performed on each of the 111 dental stone type V maxillae models of students of dentistry from Buenos Aires University [93 females and 18 males, mean age 23.70 (± 2.26) years] The mesial and distal-vestibular angles were defined on each right upper incisor, and the following segments were defined: AB (zenith - incisal edge), CD, EF, GH (apical, middle, and incisal thirds - vestibule - mesial and vestibule-distal angles) and their lengths were determined with a precision caliper. Then, the CD/AB, EF/AB and mean CD-EF/AB ratios were calculated. Shapes were assessed by four independent observers, three of whom evaluated digital images of the models, while the fourth had no access to the images, and determined the shapes using an algorithm developed from the dimensions of the studied segments. Rates and confidence intervals were determined, and Fleiss' Kappa was calculated to assess the agreement among the evaluators who worked with the images and among all of them. Average incisor length was 10 mm, and widths at CD and EF were 7.35 mm (0.65) and 8.27 mm (0.58), respectively. Regarding shapes, 51.58% (47.90-55.20) of the incisors were identified as square, 18.02% (14.50-21.90) as ovoid and 30.41% (30.00-30.90) as triangular. Fleiss' Kappa agreement was 0.71 (0.62-0.80). The application of the proposed algorithm provided a considerable level of agreement among the observers. Regarding tooth size, both the average segment length and the proportions were similar to those reported by various authors.

RESUMEN El objetivo de este trabajo fue analizar las dimensiones de las coronas clínicas de incisivos centrales superiores, y la prevalencia de cada una de las formas dentarias según diferentes formas de determinación. Se utilizaron modelos de yeso tipo V de 111 estudiantes (93 mujeres y 18 varones) con una media de edad de 23,70 (± 2,26) años. Se definieron los ángulos vestíbulo - mesial y distal para los incisivos centrales superiores derechos (1.1), se definieron los siguientes segmentos: AB (cenit - borde incisal), CD, EF, GH (tercios apical, medio e incisal - ángulos vestíbulo - mesial y vestíbulo- distal) y se determinaron sus longitudes con un calibre de precisión. Se calcularon las proporciones CD/AB, EF/AB y media CDEF/ AB. Las formas de las piezas dentarias fueron identificadas por cuatro observadores independientes, tres lo hicieron mediante la evaluación de imágenes digitales de los modelos confeccionados. El cuarto observador, sin acceso a las imágenes, asignó a cada pieza una de las formas determinadas mediante la aplicación de un algoritmo elaborado ad-hoc. Se obtuvieron tasas e intervalos de confianza y se calculó Kappa de Fleiss para valorar la concordancia entre evaluadores. La longitud promedio fue de 10 mm y el ancho en los segmentos CD y EF fueron de 7.35 mm (0.65) y 8.27 mm (0.58) respectivamente. En cuanto a formas el 51,58% (47.90-55.20) de los incisivos estudiados fueron identificados como cuadrados, el 18.02% (14.50-21.90) como ovoides y el 30,41% (30.00-30.90) triangulares. La concordancia de Kappa de Fleiss fue de 0.71 (0.62-0.80). La aplicación del algoritmo propuesto alcanzó un nivel de concordancia considerable entre los evaluadores. En cuanto al tamaño dentario, tanto la longitud promedio de los segmentos estudiados como las proporciones halladas son similares a las reportadas por diversos autores.

Expecting The Unexpected

Report of unusual presentation of two root canals in all the mandibular anterior teeth in a single patient.Incidence of two canals in individual mandibular anterior teeth ranges from 5-37% but all six anterior teeth showing two canals is a rare finding and is seen in less then 5% of the population. We report Endodontic management of such case. Conclusion:Successful endodontic therapy of a tooth demands that a dentist should have a thorough knowledge of the root canal morphology, making it mandatory towards proper radiographic evaluation and diagnosis of the status of the pulp canals as well as periapical areas. Improper diagnostic protocol may lead to failure of Endodontic treatment. The case presented here shows successful root canal treatment of all the mandibular anterior teeth with two root canals each. The frequency of mandibular anterior teeth havingtwo root canals varies from 5% to 37 % in different populations.Pulp space anatomy of mandibular anterior teeth shows high incidence of complexity which includes variation in canal configurations, number of canals and presence of isthmus. Thorough knowledge of root canal anatomy and morphology, additional radiographs taken at different angles and correct interpretation of radiographs is mandatory

Internal Lower Incisor Morphology revealed by Computerized Microtomography / Morfologia interna de incisivos inferiores reveladas por microtomografía computadorizada

ABSTRACT This study evaluated the internal morphology of lower incisors using computerized microtomography (microCT) images. Eightynine lower incisors were scanned by microCT and reconstructed with NRecon software. 2D parameters (perimeter, root length, circularity and canal diameter) and 3D parameters (volume, surface area and structure model index) were evaluated with CTAn and CTVol software. The results are presented descriptively. It was found that 89.9% of the canals had a single main root canal (type I), followed by type II (6.7%) and III (3.4%), while 5.6% of the specimens presented lateral canals and 1.1% had an apical delta. Mean volume and surface area were 31.80mm³ and 90.58mm², respectively. The most prevalent shape of the root canal at CEJ level was circular (41.6%) and 1mm from the apex, 73% of the samples were classified as oval. Lower incisors with internal anatomical variations may offer a high degree of technical complexity and may result in treatment failure.

RESUMO Este estudo avaliou a morfologia interna dos dentes incisivos inferiores utilizando imagens de microtomografia computado rizada (microTC). 89 incisivos inferiores foram escaneados por microCT e reconstruídos com o programa NRecon. Parâmetros 2D perímetro, comprimento da raiz, circularidade e diâmetro do canal e parâmetros 3D volume, área superficial e índice de modelo de estrutura foram avaliados com os softwares CTAn e CTVol. Os resultados foram apresentados de forma descritiva. 89,9% dos canais apresentaram um único canal radicular principal (tipo I), seguido pelo tipo II (6,7%) e III (3,4%). 5,6% dos espécimes apresentavam canais laterais e 1,1% delta apical. O volume médio e a área de superfície foram 31,80mm³ e 90,58mm², respectivamente. A forma mais prevalente do canal radicular no nível da CEJ foi circular (41,6%) e a 1 mm do ápice, 73% das amostras foram classificadas como ovais. Incisivos inferiores com variações anatômicas internas podem oferecer um alto grau de complexidade técnica e resultar em falha do tratamento.

Causes of impacted maxillary incisors and progresses in orthodontic treatment / 上海交通大学学报（医学版）

An impacted tooth is a tooth that cannot erupt normally when its eruption is blocked or it is erupted in the wrong direction and posi-tion. The most commonly impacted teeth is the third molar, while in the anterior region, the most common is the maxillary canine, followed by the maxillary central incisor and the maxillary lateral incisor. In recent years, the treatment of impacted maxillary incisors often uses open and closed eruption techniques with traction. Although most of the prognosis is good, traction difficulties, root resorption and alveolar bone loss are often encountered in the case of root dilacerations. This article reviews the progresses in the treatment of impacted maxillary incisors.

Progress in restorative treatments of primary incisor defects / 口腔疾病防治

@#Dental caries and trauma are the most common oral diseases in children, which could result in defects of the teeth or detention. Maintenance of the primary dentition in a nonpathologic condition is important for oral health, craniofacial development, and the overall well-being of the children. In contemporary dentistry, primary anterior teeth defects are mainly treated with drugs, restorative treatments, or both. Restorative treatment is the most preferred method and includes direct restoration, full coronal restoration, post-and-core crowns, etc. This article reviews the available information regarding a variety of restorative treatments for primary incisor defects, including their backgrounds, clinical indications, clinical pathways, and related studies. The literature review shows that intraconal direct restoration is widely used on single surfaces. There are many kinds of full coronal restorations, and each has its own advantages. Pediatric resin-bonded strip crowns and zirconia crowns are the most popular and have excellent aesthetics. The use of post-and-core crowns for primary incisors is controversial. The absorbable post may be the next research hotspot. Therefore, treatment of severely destroyed primary incisors poses a challenge for pediatric dentists, as three important considerations must be kept in mind: children′s behavioral management, preservation of the tooth structure and parental satisfaction.

Clinical performance of rensin-bonded composite strip crowns in primary incisors / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the clinical success of the treatment of maxillary anterior primary incisors caries with composite resin strip crowns.@*METHODS@#Children who presented with severe early childhood caries and were treated comprehensive caries under general anesthesia from January to December 2016 were enrolled in this study. Composite crowns using preformed celluloid crown (3M ESPE, USA) called as "strip crown technique" were applied to treat vital primary incisors with two or multiple surface cavities. Selective etchings of enamel, Universal Bond adhesive and 3M Z350 resin were used to make strip crowns. The patients returned at the end of 6, 12 and 18 months and received clinical and radiologic examinations. Dentists who did not attend the treatment evaluated the strip crowns clinically by modified United States Public Health Service (USPHS) criteria.@*RESULTS@#Four hundred eighteen restorations, placed in 127 children aged 1.17-5.75 years (average of 3.22), were evaluated. The overall retention rate was 97.8% at the end of 6 months, 93.6% at 12 months and 89.2% at 18 months. After 18 months, 28 restorations (6.7%) were totally lost and 4.1% were rated as having lost some resin material. Only four teeth (1.0%) had secondary caries at the end of 18 months and 1.4% teeth had pulpal pathology requiring root canal treatment. Composite crowns had good performance in contour and adjacent contact and improved aesthetics significantly. Twenty-nine teeth (6.9%) showed mild gingivitis and 93.1% showed healthy gingival. 11.2% of the teeth demonstrated color change because plaque accumulation and the polish could remove the stains. The complete loss of strip crowns was mainly related to eating bites.@*CONCLUSION@#Strip crowns performed well for restoring primary incisors with large or multisurface caries for periods of over 18 months. The strip crowns can be a durable and aesthetic restoration for vital carious primary incisors with adequate tooth structure after caries removal. Functional movement is an important cause of complete loss. Because of the high technical sensitivity and its requirement of the cooperation of children, strip crowns are more suitable for older and cooperative children as well as children receiving dental treatment under sedation or general anesthesia.

Clinical analysis of skeletal malocclusion, axial inclination in patients with short root anomaly of the maxillary central incisors / 口腔疾病防治

Objective @#To investigate the prevalence and distribution of skeletal malocclusion and axial inclination of the maxillary central incisors in short root anomaly (SRA) patients in Kunming city, to provide some reference and guidance for SRA patients′ clinical diagnosis and treatment and prevention in SRA patients. @*Methods@#A total of 1 000 cases were randomly selected from the CBCT database of patients admitted to the author′s hospital from January 2011 to July 2019, and a retrospective analysis was performed. A total of 27 patients with SRA were diagnosed (SRA group).The control group, consisted of 100 randomly selected patients from non-SRA patients. According to the clinical data and cephalometric data, skeletal malocclusion was divided into three subgroups: Class I skeletal malocclusion, Class II skeletal malocclusion and Class Ⅲ skeletal malocclusion. Additionally, the axial inclination of the central incisors was divided into three subgroups: the lingual inclination group, labial inclination group and normal inclination group. The two groups each according to sex, skeletal malocclusion and types of axial inclination of the maxillary central incisors were discussed. @*Results @# The prevalence rate of SRA in the selected population was 2.7%, and the prevalence of SRA in females was 3.67% (21/572) , which was higher than that in males by 1.4% (6/428), and was significantly different between sexes (χ2=4.562, P=0.033). There was a significant difference between SRA patients and control group in terms of skeletal malocclusion (χ2=8.710, P=0.013). Class Ⅲ skeletal malocclusion was the main type of skeletal malocclusion in SRA. There was a significant difference between SRA patients and control group in terms of the axial inclination of the maxillary central incisors (χ2=16.75,P<0.001). Lingual inclination of the maxillary central incisors was the main type of axial inclination of the maxillary central incisors in SRA. @*Conclusion@#There is a certain correlation between class Ⅲ skeletal malocclusion and lingual inclination of the maxillary central incisors and SRA, and the root-crown ratio and root shape of these patients should be evaluated before orthodontics are implemented.

The incisive papilla as a guide to maxillary anterior teeth position for complete dentures

Context: The incisive papilla as a guide for complete dentures. Aims: To evaluate incisive papilla as a guide to maxillary anterior teeth position for complete dentures. Settings and Design: To measure the linear distances from the incisive papilla to the maxillary central incisors in Odia population and compare it to other ethnic groups. Subjects and Methods: The subjects were selected following inclusion & exclusion criteria. The impressions of maxillary & mandibular arches were taken and poured with die stone to produce the cast. The incisive papilla & incisors were marked on casts with a pencil. The photographs of casts were traced on an acetate tracing paper. The anterior-most points of maxillary incisors, anterior, middle & posterior-most points of incisive papillae were marked on the tracing as A, I1,M, I2 respectively. The A to M and A to I2 distances were measured, analysed and compared with Caucasians, Southern Chinese, and Dravidians. Statistical Analysis: Independent sample “t” test and Analysis of Variance followed by the post-hoc Bonferroni test were used. Results: A sample of 100 subjects in the age group of 20 to 40 years with was selected. The A to M measurements of Odia population differed significantly from Caucasians but were similar to Southern Chinese population. The A to I2 measurements of Odia population differed significantly from Caucasians & Dravidians but were similar to Southern Chinese. Conclusion: The linear measurements from incisive papilla to maxillary incisors of the Odia population are similar to that of Southern Chinese but differ significantly from Caucasians and Dravidians.

CBCT study of the alveolar bone remodeling after retraction of the maxillary incisors assisting with micro-implant anchorage in maxillary protrusion adults / 口腔疾病防治

Objective@# To study the remodeling of alveolar bone after retraction of the maxillary incisors assisting with micro-implant anchorage in adult patients with maxillary protrusion by CBCT.@*Methods@#Forty patients who were treated with extraction of the maxillary first premolars with microimplant anchorage meeting the inclusion criteria were selected. The CBCT data before and after treatment were collected, and the Dolphin Imaging 3D measurement software was used to measure and analyze the height and thickness of the alveolar bone of the 80 upper central incisors and the 80 lateral incisors.@*Results @#After retraction of the incisors assisting with microimplant anchorage, the labial alveolar bone height of the maxillary central incisors decreased (0.11 ± 0.33) mm, and the lingual alveolar bone height of the maxillary central incisors decreased (0.85 ± 1.23) mm. The labial alveolar bone height of the maxillary lateral incisors decreased (0.18 ± 0.42) mm, and the lingual alveolar bone height of the maxillary lateral incisors decreased (1.13 ± 1.14 ) mm. The reduction in the lingual alveolar bone height was greater than that of the labial side, and the difference was statistically significant (P < 0.05). The labial alveolar bone thickness of the maxillary central incisors increased (the root cervix, the root media and the root apex), and the difference was statistically significant (P < 0.001). The labial alveolar bone thickness of the maxillary lateral incisors also increased (P < 0.05), while the lingual alveolar bone thickness and the total alveolar bone thickness of the maxillary central and lateral incisors decreased (P < 0.001). @*Conclusion@#In adults with maxillary protrusion, the microimplant was used to assist the reduction of the anterior teeth. The alveolar bone height of the maxillary incisors was reduced, and the palatal alveolar bone height decreased more than that of the labial side. The alveolar bone of the labrum was thickened, and the palatal alveolar bone thickness and the total alveolar bone thickness of the maxillary incisors were reduced after treatment.

Facial profile of patients with congenitally missing 2 mandibular incisors and changes of facial profile before and after orthodontic treatment by extraction of 2 maxillary premolars / 吉林大学学报(医学版)

Objective: To analyze the facial profile of the patients with congenitally missing 2 mandibular incisors, and to investigate the changes of facial profile of the patients before and after orthodontic treatment by extraction of 2 maxillary premolars. Methods: The cephalometrics of 64 patients with congenitally missing 2 mandibular incisors were collected. The initial cephalometrics of 64 patients were used to characterize the facial profile. A total of 38 cases among all the 64 patients underwent the orthodontic treatment by extraction of 2 maxillary premolars, and the initial and final cephalometrics were used to compare the changes of facial profile before and after treatment. The cephalometric measurement (including hard tissue and soft tissue items) was performed and the results were analyzed statistically. Results: Compared with the normal values, the overjet, overbite, ANB, U1-NA angle, face angle, Y axis, Pg-NB, face convexity, soft tissue facial angle, H angle, and men to labial sulcus to H-Line in the patients with congenitally missing 2 mandibular incisors were increase d, SNB, L1-NB angle, L1-NB distance, L1-MP, occlusal plane angle, mentolabial sulcus angle were decreased, and the differences were statistically significant (P<0. 05). After orthodontic extraction treatment, the overjet, overbite, U1-NA angle, U1-NA distance, U1-SN, H angle, and subnasale to H-Line of the patients were decreased, the L1-NB angle, L1-NB distance, L1-MP, occlusal plane angle, Pg-NB, and mentolabial sulcus angle were increased; the differences were statistically significant (P<0. 05). Conclusion: The mandibular development is insufficient but the chin development is adequate in the patients with congenitally missing 2 mandibular incisors, with larger overjet and overbite, lingually inclined mandibular incisors, deeper and sharper mentolabial sulcus. After treatment by extraction of 2 maxillary premolars, the overall appearance of the lateral profile of the patients remains unchanged, but the occlusion of anterior teeth is significantly improved.

Application of strip crown form in aesthetic restoration of mandibular deciduous incisors in severe childhood caries / 中华医学美学美容杂志

Objective To explore the feasibility and effectiveness of aesthetic restoration of caries of mandibular deciduous incisors with strip crown form of maxillary deciduous incisors.Methods A total of 64 patients (202 teeth) with symmetrical caries of bilateral mandibular central incisors or lateral incisors were randomly selected.The opposite maxillary incisors were restored with strip crowns form and the opposite incisors were restored with resin composite.The effects of the two methods and the incidence of complications were compared three months,six months and twelve months after treatment.Results Three months after treatment,there was no significant difference in the success rate between the two groups.Six months after treatment,there was significant differencein the marginal adaptation between the two groups (x2 =3.919,P =0.048);12 months after treatment,there was significant difference in the restoration integrity of the two groups and the incidence of secondary caries (x2 =5.027,P =0.025;secondary caries x2 =4.369,P =0.037).Conclusions The strip crown form of maxillary primary incisors can be used for aesthetic restoration of caries of mandibular primary incisors,and its effect is better than that of direct resin filling.The strip crown form for mandibular primary incisors needs to be developed and produced urgently.

Influence of anterior load and restorative procedure on maxillary incisors with different cervical wear morphologies / Influência do procedimento restaurador e de contato anterior em incisivos superiores com diferentes morfologias de desgaste cervical

The aim of this study was to evaluate the influence of different anterior load type and restorative procedure on stress distribution of maxillary incisors with different noncarious cervical lesions (NCCLs) morphologies. Three-dimensional models of a maxillary incisor were generated. Beyond the sound model (SO), five NCCLs morphologies were simulated: shallow (SH), notched (NO), concave (CO), wedge-haped (WS) and irregular with dual center (IR' and IR"). Composite resin restoration of all the models was simulated (R). Two different anterior loads were applied: 100N on palatine middle third (ML) and 500 N on palatine incisal third (IL). The data were obtained in MPa using the Maximum Principal Stress and Von Mises criteria and the statistical analysis was performed (paired t-test with 95% confidence level). The IL provided higher compressive stress than ML, mainly on WS (-136.3MPa), IR" (-117.5) and NO (-71.1 MPa). The highest tensile stress found within the restored models was on NOR with IL (19,1 MPa). The Von Mises results showed higher stress concentration on non-restored and IL models (p<0.001). The anterior load type and restorative status were determinant factors on stress distribution pattern changes, whereas NCCLs morphologies had little influence in maxillary incisors.

O objetivo deste estudo foi avaliar a influência de diferentes tipos de contatos anteriores e procedimentos restauradores na distribuição de tensões de incisivos superiores com diferentes morfologias de lesões cervicais não-cariosas (NCCLs). Modelos tridimensionais de um incisivo central superior foram gerados. Além do modelo hígido (SO), foram simuladas cinco morfologias de NCCLs: rasas (SH), entalhadas (NO), côncavas (CO), em forma de cunha (WS) e irregulares com centro duplo (IR' e IR''). Restauração com resina composta em todos os modelos foi simulada (R). Dois contatos anteriores diferentes foram aplicadas: 100N no terço médio palatino (ML) e 500N no terço incisal palatino (IL). Os dados foram obtidos em MPa utilizando os critérios de Tensão Máxima Principal e de Von Mises e a análise estatística foi realizada (teste t pareado com nível de significância de 95%). A IL proporcionou maior estresse compressivo que ML, principalmente em WS (-136,3MPa), IR "(-117,5) e NO (-71,1 MPa). A maior tensão de tração encontrada nos modelos restaurados foi na NOR com IL (19,1 MPa). Os resultados de Von Mises mostraram maior concentração de estresse nos modelos não restaurados e IL (p <0,001). O tipo de contato anterior e a presença de restauração foram fatores determinantes nas alterações do padrão de distribuição de estresse, enquanto as morfologias dos NCCLs tiveram pouca influência nos incisivos superiores.

Factores asociados a la recesión de la papila interdental de incisivos centrales superiores en adultos del Hospital Central de la Fuerza Aérea del Perú / Factors associated with the recession of the interdental papilla of the upper central incisors in adults of the Peruvian Air Force Central Hospital

Objetivo: Identificar los principales factores asociados a la recesión de la papila interdental de incisivos centrales superiores. Material y métodos: Se analizó una muestra no probabilística de 86 pacientes de la sección de Periodoncia e Implantes del Departamento de Estomatología del Hospital Central de la Fuerza Aérea del Perú. El tipo de estudio fue observacional, correlacional simple, transversal y prospectivo. Se evaluaron clínicamente factores como forma coronal dentaria y biotipo gingival; y radiográficamente distancias de la unión cemento esmalte proximal al punto de contacto interdentario (UCEp-PC), punta de la papila al punto de contacto interdentario (PP-PC), cresta ósea al punto de contacto interdentario (CO-PC), cresta ósea a la unión cemento esmalte proximal (CO-UCEp), ancho interdental (AI), ancho de la cresta ósea (AC) y ancho de la punta de la papila (APP). Resultados: En todos los pacientes de estudio, el nivel de recesión, CO-PC y APP fueron predictores individuales significativos (p<0,05) de la altura papilar (AP). En pacientes con recesión papilar, CO-PC, APP y PP-PC fueron predictores significativos (p<0,05) de AP. Además, CO-PC fue el único predictor significativo (p<0,001) de AP en pacientes sin recesión papilar. Conclusiones: Las distancias PP-PC, CO-PC y APP son los principales factores asociados a la recesión de la papila interdental de incisivos centrales superiores y en conjunto predicen la altura papilar.

Objectives: To identify the main factors associated with the recession of the interdental papilla of the upper central incisors. Material and Methods: A non-probabilistic sample of 86 patients from the section of the Periodontal and Implant Section of the Department of Dentistry of the Peruvian Air Force Central Hospital was analyzed. The study was observational, correlational, transversal and prospective. Factors such as coronal tooth shape and gingival biotype were clinically evaluated; and radiographically, with the parallel technique, distances of the cement enamel proximal junction to the point of interdental contact (UCEp-PC), papilla tip to the point of interdental contact (PP-PC), bone crest to the point of interdental contact (CO-PC), bone crest to the cement enamel proximal junction (CO-UCEp), interdental width (AI), width of the bone crest (AC) and width of the tip of the papilla (APP). Results: In all study patients, the recession level, CO-PC and APP were significant individual predictors (p <0.05) of papillary height (PA). In patients with papillary recession, CO-PC, APP and PP-PC were significant predictors (p <0.05) of AP. In addition, CO-PC was the only significant predictor (p <0.001) of AP in patients without papillary recession. Conclusions: The PC, CO-PC and APP PP distances are the main factors associated with recession of the interdental papilla of upper central incisors and together predict papillary height.