The Prevalence, Severity and Pattern of First Permanent Molars’ Dental Caries in Children Attending A Postgraduate Dental Hospital: A Retrospective Study

@#Introduction: First permanent molars (FPMs) erupt early and their anatomy and location leave them susceptible to dental caries. This study aimed to retrospectively determine the prevalence, severity and pattern of dental caries of FPMs and investigate their relationship if any with demographics and medical health status of the partcipants. Methods: This was a retrospective cross-sectional study. A sample of the digital case notes and radiographs of children aged 5 to 12 years who attended the only postgraduate dental hospital in Dubai were accessed. The recorded data included the children’s demographic variables and the carious status of each FPM as recorded in the notes on the initial assessment. Descriptive and statistical analyses were conducted (P<0.05). Results: A total of 2984 FPMs were obtained from the digital records of 774 children. Their mean age was 8.07 (±2.23) years and only those that met the inclusion criteria were included in the study. The prevalence of dental caries and mean Decayed Missing Filled Surfaces of FPMs, were 42% and 0.3 (±0.04), respectively. The most prevalent decayed surface was the occlusal (29.2%), followed by mesial, buccal, palatal/ lingual, distal surfaces (24.2 %; 6.6 %; 3.1 %; 2.3 %) respectively. Children with medical problems and/or special needs had a significantly higher level of caries in the buccal surfaces (12.3%) (P=0.042). Conclusion: Caries of FPMs in a sample of Dubai children studied was prevalent, especially in those with special healthcare needs, thus indicating a necessity for targeted prevention and treatment focused on these keystone teeth.

Extracción terapéutica de primeros molares Permanentes severamente destruidos en dentición mixta

En dentición mixta, el 1°Molar permanente es el más susceptible a caries, que desencadena un ciclo restaurador repetitivo y pérdida. El objetivo de este estudio fue evaluar factores determinantes de la extracción terapéutica de 1°Molares permanentes severamente destruidos en dentición mixta antes de la erupción del segundo molar permanente con un favorable cierre espontáneo del espacio residual. La metodología consistió en una revisión sistemática exploratoria en PubMed mediante búsqueda estratégica/específica. Incluyó diez artículos que abordaron factores como la edad cronológica ideal, etapa de desarrollo del segundo premolar y molar permanente, presencia del tercer molar, cierre espontáneo residual, pronóstico, y necesidad de tratamiento ortodóncico. En conclusión, la extracción terapéutica del 1°Molar antes de la erupción del segundo molar permanente está asociada con un favorable cierre espontáneo del espacio residual. Se evidencia mayor éxito con la presencia del tercer molar, segundo molar en etapa E y segundo premolar en etapa F (Demirjian).

Abstrato: Em dentição mista, o 1°molar permanente é o mais suscetível a cáries, desencadeando um ciclo restaurador repetitivo e perda. O objetivo deste estudo foi avaliar fatores determinantes da extração terapêutica de 1°molares permanentes severamente destruídos na dentição mista antes da erupção do segundo molar permanente com uma região espontânea favorável do espaço residual. A metodología utilizada no PubMed consistiu em uma revisão exploratória por meio de busca estratégica/específica. Foram incluídos dez artigos, abordando fatores como a idade cronológica ideal, estágio de desenvolvimento do segundo pré-molar e molar permanente, presença do terceiro molar, cierre espontâneo residual, pronóstico e necessidade de tratamento ortodôntico. Em conclusão, a extração terapêutica do 1°molar permanente antes da erupção do segundo molar permanente está associada a um fechamento espontâneo favorável do espaço residual. Maior sucesso está descrito quando na presença de terceiro molar, segundo molar no estágio E e segundo pré-molar no estágio F (Demirjian).

During mixed dentition, the 1st permanent molar is the most susceptible to caries, triggering a repetitive restorative cycle and loss. This study aimed to evaluate determinants of therapeutic extraction of severely damaged 1st permanent molars in mixed dentition before the eruption of the second permanent molar with favorable spontaneous closure of the residual space. The methodology involved a scoping review on PubMed using a specific search strategy. Ten articles were included addressing factors such as the ideal chronological age, stage of development of the second premolar and permanent molar, presence of the third molar, residual spontaneous closure, prognosis, and need for orthodontic treatment. In conclusion, therapeutic extraction of the 1st molar before the eruption of the second molar is associated with favorable spontaneous closure of the residual space. Greater success is evident with the presence of the third molar, the second molar in stage E, and the second premolar in stage F (Demirjian).

Cone beam computed tomography study on the root and root canal morphology of mandibular first permanent molars in a Tibetan population / 口腔疾病防治

Objective @#To investigate and analyze the root and root canal morphology of mandibular first molars (MFMs) in the Tibetan population using cone-beam computed tomography (CBCT) and to provide references for clinical root canal treatment in the Tibetan population. @*Methods@#This study was reviewed and approved by the Ethics Committee, and informed consent was obtained from the patients. CBCT imaging data of 300 mandibular first molars from 300 Tibetan patients were included. Patient age, the number of roots in mandibular first molars were recorded. The morphology and incidence of mesial root and mesial root canals and the morphology and incidence of distal root and distal root canals were statistically analyzed by Vertucci classification. @*Results @#There were 198 double-root teeth and 102 three-root teeth in the 300 mandibular first permanent molars. Among the three-rooted molars, 1 case had mesiolingual roots, and the rest had distolingual roots. The incidence rate of the distolingual root was 33.7%(101/300). The most common root canal configuration was Vertucci Ⅳ 65.7% (197/300), followed by Vertucci Ⅱ 20.3% (61/300) in the mesial roots. The overall incidence of middle mesial canals (MMCs) was 6% (18/300), with the highest incidence of MMCs in the 20-40 year-old group at 9% (9/100). The distal roots canals of single-distal-rooted mandibular first molars were mainly Vertucci Ⅰ 66.8% (133/199), followed by Vertucci Ⅱ 14.6% (29/199) and Vertucci Ⅳ 11.6% (23/199). For the mandibular first permanent molars with two distal roots, 96% (97/101) of the distal buccal roots and 100% (101/101) of the distal lingual roots were Vertucci Ⅰ root canals. @*Conclusion@# The root and root canal morphology of mandibular first permanent molars in a Tibetan population is complex and variable. Approximately one-third of patients have distolingual roots, and clinicians should carefully explore the root canals under the guidance of CBCT.

Caries status and related factors among 12-year-old children in Yangpu District， Shanghai / 上海预防医学

ObjectiveTo investigate the prevalence and risk factors of dental caries and its related influencing factors in 12-year-old children in Yangpu District， Shanghai， and to provide relevant data support for the formulation of oral health policies and measures for children. MethodsIn 2021， 839 12-year-old children were randomly selected from five ordinary junior high schools in Yangpu District. The investigation included an oral health examination and a questionnaire survey on factors related to dental caries. Logistic regression analysis was used to analyze the influencing factors of dental caries. ResultsAmong the 839 participants， data from 830 were included. Among them， 426 were male （51.3%） and 404 were female （48.7%）. Of the 830 children， 203 had dental caries， resulting in a caries prevalence of 24.46%， a caries supplemental filling ratio of 32.6%， and a DMFT of 0.63. Multivariate logistic regression analysis revealed that a mother’s education level of college or above （OR=0.849，95% CI： 0.732‒0.984）， brushing teeth twice a day （OR=0.827，95%CI： 0.703‒0.973）， and the caregiver brushing teeth twice a day （OR=0.843， 95%CI： 0.726‒0.983） were effective factors in reducing the caries rate. Factors associated with childhood dental caries included consuming sweets ≥1 time per day （OR=1.397，95%CI： 1.197‒1.342） and female gender （OR=1.482，95%CI： 1.347‒1.671）. ConclusionThe prevalence of dental caries among 12-year-old children in Yangpu District is 24.46%. Gender， maternal education， the frequency of children's toothbrushing， the frequency of sweet consumption， and the caregiver’s toothbrushing frequency are the main factors affecting the prevalence of dental caries in children.

Erupción dentaria y actividad de caries: ¿es un factor de riesgo en adolescentes?

Resumen Objetivo: describir el comportamiento, distribución y severidad de las lesiones de caries en las superficies oclusales de los segundos molares permanentes. Relacionarlo a su etapa de erupción y presencia de actividad en el resto de la cavidad bucal. Metodología: Se realizó un estudio descriptivo en una muestra de conveniencia de 100 adolescentes, de ambos sexos, (edad promedio=13,39±0,94 años). Los padres respondieron un cuestionario sobre aspectos socioeconómicos y salud general y los adolescentes sobre dieta y hábitos de higiene. Dos examinadoras calibradas realizaron el examen clínico de acuerdo a los criterios de ICDAS II en todas las superficies erupcionadas, así como el mapeo de la cara oclusal y la etapa de erupción de los segundos molares permanentes. Resultados: la prevalencia de caries fue de un 97% y la extensión (CPOD modificado) de 8,45± 5,10. El 82% de los adolescentes con experiencia de caries presentaba lesiones activas y el 62% de los carioactivos presentaban lesiones únicamente en las caras oclusales de los segundos molares permanentes. Se observó mayor prevalencia de lesiones de caries activas en los estadíos I y II de erupción de los segundos molares permanentes, siendo los sitios más afectados la fosa central y mesial y la fosa central y distal, respectivamente. Conclusiones: La erupción activa de molares significa una etapa de riesgo para las personas que debe ser considerada al momento priorizar y establecer programas de salud bucal.

Resumo Objetivo: descrever o comportamento, distribuição e severiidade das lesões de cárie nas superfícies oclusais dos segundos molares permanentes. Relacionar com seu estágio de erupção e presença de atividade no resto da cavidade oral. Metodologia: Foi realizado um estudo descritivo em uma amostra de conveniência de 100 adolescentes, de ambos os sexos, (média de idade = 13,39 ± 0,94 anos). Os pais responderam a um questionário sobre aspectos socioeconômicos e de saúde geral e os adolescentes sobre alimentação e hábitos de higiene. Dois examinadores calibrados realizaram o exame clínico de acordo com os critérios do ICDAS II em todas as superfícies erupcionadas, além de mapear a superfície oclusal e o estágio de erupção dos segundos molares permanentes. Resultados: a prevalência de cárie foi de 97% e a extensão (CPOD modificado) de 8,45 ± 5,10. 82% dos adolescentes com experiência de cárie tinham lesões ativas e 62% dos carioativos tinham lesões apenas nas superfícies oclusais dos segundos molares permanentes. Maior prevalência de lesões de cárie ativas foi observada nos estágios I e II de erupção dos segundos molares permanentes, sendo os locais mais acometidos a fossa central e mesial e a fossa central e distal, respectivamente. Conclusões: A erupção ativa de molares representa uma etapa de risco para as pessoas que deve ser considerada na priorização e estabelecimento de programas de saúde bucal.

Abstract Objective: to describe the behavior, distribution, and severity of lesions on the occlusal surfaces of the second permanent molars. Relate it to its stage of eruption and presence of activity in the rest of oral cavity. Methodology: A descriptive study was conducted in a convenience sample of 100 adolescents of both sexes (mean age = 13.39 ± 0.94 years). The parents answered a questionnaire on socioeconomic characteristics and general health, and the adolescents, one on food and hygiene habits. Two calibrated examiners recorder caries according to ICDAS II on all the dental surfaces . They also mapped the occlusal surface and eruption stage of the second permanent molars. Results: the prevalence of caries was 97%, and the extension (modified DMFT) was 8.45 ± 5.10. Eighty-two percent of the adolescents with caries experience had active lesions, and 62% of those with caries had lesions only on the occlusal surfaces of the second permanent molars. A higher prevalence of active caries lesions was observed in eruption stages I and II of the second permanent molars. The most affected sites were the central and mesial fossa and the central and distal fossa. Conclusions: Active molar eruption entails a risk stage that should be considered when prioritizing and developing oral health programs.

Afectación del primer molar permanente y efecto de una estrategia educativa en una institución educativa de la ciudad de Medellín: 2016-2019 / Affectation of the first permanent molar and effect of an educational strategy in an educational institution in the city of Medellin: 2016-2019

RESUMEN Introducción: el desconocimiento sobre la importancia del primer molar permanente en la salud bucal continúa siendo un problema en gran parte de la población. El objetivo fue evaluar la efectividad de una estrategia educativa para la conservación del primer molar permanente (PMP), en escolares de una Institución Educativa en Medellín. Métodos: estudio de seguimiento a una intervención educativa entre los años 2016 y 2019 en una muestra de 35 escolares entre 12 y 13 años, a quienes se les realizó tamizaje bucal para observar el COP-D modificado y el índice de placa según Silness & Loe. Se realizaron encuesta a 35 padres de familia sobre saberes y prácticas en salud bucal y el primer molar permanente, y actividades educativas con énfasis en el cuidado del primer molar a los escolares. Los datos fueron analizados a través de estadística descriptiva y bivariada mediante las pruebas de Mac Nemar, Wilcoxon y Chi cuadrado de Pearson. Resultados: después de la estrategia aumentó la proporción de padres y cuidadores que identificaron el primer molar permanente y su importancia (38,7% vs 67,6%), la frecuencia de caries no cavitacional en PMP disminuyó (45,7% vs 26,5%), se observó un aumento en el reporte de uso de la seda dental (40% vs 67,6%) y de la consulta odontológica de los escolares (74,3% vs 97,1%), además de una mejoría significativa en la calidad del cepillado (Me % placa = 85% vs 30%). Conclusión: se demostró la efectividad de la intervención educativa respecto a los conocimientos sobre el PMP y prácticas de la higiene bucal, como factores protectores para su permanencia en boca.

ABSTRACT Introduction: the lack of knowledge about the importance of the first permanent molar in oral health continues to be a problem in a large part of the population. The objectivewas to evaluate the effectiveness of an educational strategy for the preservation of the permanent first molar (PMP) in school children of an educational institution in Medellin. Methods: follow-up study of an educational intervention between 2016 and 2019 in a sample of 35 schoolchildren between 12 and 13 years of age, who were screened for modified CPO-D and plaque index according to Silness & Loe. Thirty-five parents were surveyed about knowledge and practices in oral health and the permanent first molar, and educational activities with emphasis on the care of the first molar were carried out for schoolchildren. The data were analyzed through descriptive and bivariate statistics using Mac Nemar, Wilcoxon and Pearson's Chi-square tests. Results: after the strategy, the proportion of parents and caregivers who identified the first permanent molar and its importance increased (38.7% vs 67.6%), the frequency of non-cavitational caries in PMP decreased (45.7% vs 26.5%), an increase was observed in the reported use of dental floss (40% vs 67.6%) and dental consultation of school children (74.3% vs 97.1%), as well as a significant improvement in the quality of brushing (Me % placa = 85% vs 30%). Conclusion: the effectiveness of the educational intervention was demonstrated with regard to knowledge about PMP and oral hygiene practices, as protective factors for its permanence in the mouth.

Location, incidence and clinical implications of the root canal isthmus / 口腔疾病防治

@#Root canal isthmus(RCI) is defined as a narrow, ribbon-shaped communication between two root canals that contains pulp or tissue derived from pulp. Any root that contains two or more root canals has the potential to contain an isthmus. The incidence of RCI from different tooth positions varies, with the highest RCI incidences usually found in the mesial root of the mandibular first molar and the mesiobuccal root of the maxillary first molar. The presence of RCI increases the difficulty of root canal therapy and introduces uncertainty regarding the prognosis for dental treatment. It is recommended to use CBCT and dental microscopy to identify teeth with suspected RCI in clinical practice. At the same time, for treatment of teeth with RCI, appropriate instruments should be selected, and enhanced root canal irrigation assisted by ultrasound should be considered to improve the success rate of root canal treatment and endodontic root-end surgery. The current technology still has some limitations regarding the cleaning and filling of RCI and additional research and development. Improvement of the corresponding technology and equipment is a current research hotspot and a future research direction.

Evaluation of glide path preparation and shaping ability of two nickel-titanium engine driven systems in moderate curved root canals / 上海交通大学学报（医学版）

Objective:To evaluate the clinical application effect of two nickel-titanium engine driven systems on moderate curved root canals. Methods:Ninety mesial root canals with moderate curvature of extracted human first mandibular permanent molar were randomly divided into three groups: M3 PRO Group, MTwo group and K group. The glide path was firstly prepared by using #10/04 file in M3 PRO group and MTwo group and #10 file in K group respectively.Then the preparation of root canals up to #25 was performed according to the instruction manual in each different group using standardized technique. All data including time required in glide path preparation, shaping preparation, total root canals preparation and changes of working length in root canal were recorded and analyzed statistically by using Analysis of Variance (ANOVA) and LSD-t tests (P<0.05). Results:Root canal glide path preparation time: MTwo group showed significantly less preparation time while M3 PRO group exhibited significantly the longest preparation time. There was significant difference between MTwo group and M3 PRO group (P=0.001). Root canal shaping preparation time: M3 PRO group showed significantly less preparation time while K group exhibited significantly the longest preparation time. Both MTwo group and M3 PRO group showed significantly less preparation time than K group (P=0.004, P=0.001), but there was no significant difference between MTwo group and M3 PRO group (P=0.573). Total root canal preparation time: MTwo group showed the shortest time while K group exhibited the longest time. There were significant differences between MTwo group, M3 PRO group and K group (P=0.004, P=0.033), but no significant difference between MTwo group and M3 PRO group (P=0.451). Changes of root canal working length: There were significant differences among the three groups (P=0.037, P=0.037, P=0.000). M3 PRO group showed a minimal change while K group exhibited significant changes. Conclusion:MTwo nickel-titanium engine driven system with #10/04 file preform a high efficiency in glide path preparation, whilst M3 PRO nickel-titanium engine driven system show less changes in working length. Under the circumstances where the total time required for root canal preparation is not significant, M3 PRO nickel-titanium engine driven system is more suitable for root canal preparation in moderate curved root canals.

Review and suggestion on the evaluation of the effect and the benefit of a pit and fissure sealant project / 口腔疾病防治

@#As a professional method to prevent decayed teeth and an oral public health project, pit and fissure sealant is widely used domestically. How to evaluate the effect and benefit of the community pit and fissure closure project, especially the community full coverage pit and fissure closure project, requires investigation. The Guangzhou Children′s Pit and Fissure Sealing Project was carried out in an orderly manner and was administered normatively. A retrospective cohort study with use of a sample survey was used in this program. According to cavity occurrence and reservations of sealant in the first permanent molar, the samples were divided into the following two groups: the sealing group with indication and the sealing group without indication. Reservations of sealant, cavity incidence, reduced incidence, net profit, cost-effectiveness and cost-benefits of the program were evaluated. Some promotable experiences were summarized during this project. Various relevant theories and reports of the pit and fissure sealant project evaluation were reviewed and previous studies were discussed in this article. By analyzing the methods and results of the pit and fissure sealant project in Guangzhou, suggestions are made for project evaluation, especially sample grouping and evaluation indicators, which was refer to a further study for the pit and fissure sealing project.

Prevalence of dental caries and associated factors among 10-12-year-old students in Chongqing / 华西口腔医学杂志

OBJECTIVE@#To investigate the caries status of the first permanent molars in urban and rural children aged 10-
12 in Chongqing and analyze the related factors in order to provide a theoretical basis for the prevention and treatment of children's caries and targeted suggestions for oral health education.@*METHODS@#A multi-stage, stratified, cluster, and random sampling method was used to extract 5 057 children from 18 schools in three districts and three counties in Chongqing for oral health examination and questionnaire survey from March to May 2018.@*RESULTS@#The total caries rate of the first permanent molar was 39.2%. The decayed-missing-filled tooth was 0.84±1.20. The rate of filling teeth was 3.4%. The rate of pit and fissure sealing was 6.1%. The prevalence of the first permanent molars was significantly different between men and women, between urban and rural areas, between only children and non-only children, and between ethnic minorities and Han nationality (P<0.001). The gap between the pit and fissure sealing was significantly different between urban and rural areas (P<
0.001). Multiple logistic regression analysis showed that many independent factors influence the occurrence of caries, including the frequency of brushing teeth every day, the frequency of eating desserts, the habit of eating dessert/drinking milk before going to bed, whether only-children or not, and parents' education background, among others.@*CONCLUSIONS@#The first permanent molars of children aged 10-12 in Chongqing have a high rate of caries but low rates of pit and fissure sealing and dental caries filling. The difference between urban and rural areas is large, children's oral health knowledge is scarce, and children have bad oral hygiene behaviors and eating habits. Children's oral health education must be strengthened, oral health preaching must be implemented in schools, the oral health knowledge of children in school must be improved, and urban-rural differences must be minimized.

Effect analysis of ceramic onlay to repair serious dental defects in young permanent molars / 华西口腔医学杂志

OBJECTIVE@#To analyze the effect of ceramic onlay to repair serious defects in young permanent molars.@*METHODS@#Sixty patients with defects in young permanent molars were selected. The patients were randomly divided into two groups. One group was restored with ceramic onlay, and the other used resin composite to direct filling. Follow-up visit was conducted at 3, 6, 12, and 24 months after treatment. Modified USPHS/Ryge criteria were used to evaluate the effect of restoration. The occlusal courses were recorded by the T-Scan Ⅲ system in intercuspal position. Gingival and food impaction were recorded. The effect of the two restorative methods, the recovery of occlusal function, and the gingival and approximal conditions were analyzed.@*RESULTS@#At 12 months after restoration, the marginal fitness in the onlay group was significantly better than that in the resin group (P0.05). The gingival and approximal conditions also demon-strated no stati-stical differences (P>0.05).@*CONCLUSIONS@#The ceramic onlay repair method is better than resin composite filling in marginal fitness, surface smoothness, and recovery of the occlusal function when restoring young permanent molars with serious defects.

CBCT study on root and root canal morphology of maxillary second permanent molars in the Guangfu population in the Lingnan area / 口腔疾病防治

Objective @#To research the root and root canal morphology of maxillary second permanent molars in the Guangfu population of the Lingnan area.@*Methods@#A total of 1220 maxillary second permanent molars were collected from the 723 CBCT images of the Guangfu population. The root and root canal configurations were observed and counted, and the morphological characteristics and changes were compared and analyzed.@*Results@# The maxillary second permanent molars included 709 three-root molars, 417 double root molars, 68 single root molars and 26 four-root molars. The difference in the detection rate of each root type in different sex and age groups was not statistically significant (P > 0.05). Root canal morphdogy of maxillary second permanent molars: type Ⅷ (3-3) was the most common type of root canals in single root molars, accounting for 63.25%. Significant differences in the detection rates of canal configurations were noted among the three subtypes of fused root canals in double root molars (P < 0.01). Root canal morphology of the mesiobuccal root of the three-root molars was mainly typeⅠ (1-1), significantly accounting for 78.84%. Significant sex and age differences were noted in the detection rate of type Ⅰ and Ⅳ root canals (P < 0.01). In addition, 75.86% of maxillary second permanent molars had symmetrical roots, and 73.64% of the bilateral teeth had symmetrical roots and canals.@*Conclusion@#The root and root canal morphology of maxillary second permanent molars in the Guangfu population in the Lingnan area are different compared with other areas at home and abroad.

Clinical observations of all-ceramic restorations of children’s first permanent molars with severe defects / 口腔疾病防治

Objective @#To explore the therapeutic efficacy of chairside CEREC all-ceramic restorations in children with first permanent molars with severe defects and to summarize the clinical methods and procedures.@*Methods@# Forty teeth of 7-15 years old thirty-four children with first permanent molars with severe defects were selected. After careful tooth preparation, a total of 40 all-ceramic restorations (8 inlays, 32 onlays) were designed and manufactured using the CEREC 3D system, and all prostheses were bonded with composite resin cement. Immediately after treatment and after 24 months, the subjective satisfaction of the patients was assessed. The clinical efficacy was analyzed using modified USPHS criteria at 12 months and 24 months. Evaluations included secondary caries, marginal adaptation, surface texture, color matching, fracture, anatomical form, adjacency relationship and gingival health.@*Results @# For the 40 all-ceramic restorations of the first permanent molars, after 24 months, 100% of the teeth were grade A for secondary caries, surface texture and fracture of the prosthesis, and 85% of the teeth were up to grade A for the other indexes at 12 and 24 months. There were no significant differences (P > 0.05) between 12 months and 24 months. Immediately after treatment and after 24 months, the subjective satisfaction of the patients was greater than 94%. @*Conclusion @#Application of the CEREC 3D system had a clear curative effect and resulted in high satisfaction in the repair of permanent molars with severe defects in children.

A Morphometric Study of the Stainless Steel Permanent Molar Crown with Three-Dimensional Scanner / 대한치과재료학회지

The aim of this study was to compare the morphological characteristics of two types of stainless steel permanent molar crowns using three-dimensional scanners and the morphological changes of these crowns after crimping. Two types of stainless steel permanent molar crowns, PO-96 and PERMACROWN were scanned using three-dimensional scanner. Crown size, crown index (ratio of buccolingual diameter to mesiodistal diameter at height of contour), cervical convergency of crown were measured. Stainless steel crowns were crimped and re-scanned with three-dimensional scanner. Morphological changes of stainless steel permanent molar crowns were analyzed. As for the crown index, maxillary PERMACROWN was larger buccolingually and smaller mesiodistally than maxillary PO-96 and mandibular PERMACROWN was smaller buccolingually and larger mesiodistally than mandibular PO-96. Maxillary PO-96 was more convergent to cervical mesiodistally than maxillary PERMACROWN and mandibular PO-96 was more convergent to the cervical mesiodistally, buccolingually than mandibular PERMACROWN. Both types of stainless steel permanent molar crowns showed reduction of cervical circumference after crimping. Two products were morphologically different in crown size, shape and cervical convergence. Although both types of stainless steel permanent molar crowns are pre-contoured type, additional crimping is needed to achieve better marginal adaptation.

Caries en los primeros molares permanentes de estudiantes de la enseñanza secundaria / Dental decays in the first permanent molars of secondary teaching students

Se realizó un estudio descriptivo y transversal de los 694 estudiantes de la Escuela Secundaria Básica Camilo Cienfuegos Gorriará de Santiago de Cuba, durante el trimestre de enero a marzo del 2015, con vistas a determinar la afectación por caries en el primer molar permanente. Para el análisis de la información se empleó el porcentaje y entre los principales resultados se obtuvo que la mayoría de los examinados (74,0 por ciento) presentara caries en al menos uno de dichos molares, con una mayor frecuencia del sexo femenino y la edad de 13 años (45,6 y 77,6 por ciento, respectivamente), mientras que los molares inferiores fueron los más dañados (26,5 por ciento) y las fosas y fisuras, las superficies dentales más afectadas (5,1 por ciento). Finalmente, se recomendó intensificar los programas de atención estomatológica a escolares de 12 a 15 años de edad

A descriptive and cross-sectional study of 694 students from Camilo Cienfuegos Gorriarán secondary school in Santiago de Cuba was carried out from January to March, 2015 with the purpose of determining the disorder due to dental decays in the first permanent molar. The percentage was used to analyze the information and among the main results it was found that most of those examinated (74 percent) presented dental decay in at least one of the molars, with a higher frequency in the female sex and 13 years students (45.6 and 77.6 percent respectively), while the most damaged were the lower molars (26.5 percent); fossas and fissures were the most affected dental surfacies (5.1 percent). Finally, it was recommended to intensify the stomalogical care programs to school children from 12 to 15 years

Influencia de los determinantes sociales en la salud del primer molar permanente / Influence of the social determinants in the first permanent molar health

Introducción: el proceso salud enfermedad depende de múltiples y complejas condiciones y no se rige solamente por las leyes conocidas de las ciencias naturales, sino que abarca también influencias psicológicas, socioeconómicas y ambientales. Estas son consideradas determinantes sociales de salud. Los factores causales que clínicamente producen la caries están bien identificados, pero no los determinantes socialesos a su prevalencia y menos asociados al primer molar permanente, considerado por diferentes autores como llave de la oclusión. Objetivo: determinar la salud del primer molar permanente, relacionado con algunos determinantes sociales de la salud en escolares de 11 a 16 años de edad. Materiales y métodos: para ello se decidió realizar una investigación observacional descriptiva prospectiva y transversal con el objetivo de determinar la salud del primer molar permanente, relacionado con algunos determinantes sociales de la salud en escolares de 11 a 16 años de la Escuela Secundaria Básica “Fermín y Yolanda” del municipio Unión de Reyes de septiembre 2014 de a abril de 2015. Resultados: se encontró que la mayoría de los adolescentes eran del sexo femenino, y tenían entre 13 y 14 años de edad. La mayoría de las familias de los adolescentes eran disfuncionales. De las barreras para conductas saludables estudiadas, la que más incidió fue la ingestión de alimentos que expenden alrededor de la escuela con el 95,3%. Conclusiones: a pesar de estos resultados el 60,7% de los molares permanentes eran saludables(AU).

Introduction: the health-disease process depends on multiple and complex conditions and it is not only ruled by the acknowledged laws of the natural sciences. It also includes psychological, socioeconomic and environmental influences. These are considered health social determinants. The causal factors clinically producing caries are well identified, but the social determinants related with its prevalence are not, less those associated to the first permanent molar considered by several authors as the key of the occlusion. Aim: to determine first permanent molar health related with several health social determinants in students aged 11-16 years. Materials and methods: a cross-sectional, prospective, descriptive and observational research was carry out with the aim of determining the health of the first permanent molar that is related with several health social determinants in students aged 11-16 years of the Basic Secondary School (Junior High School in the United States) “Fermin y Yolanda”, of the municipality Unión de Reyes from September 2014 to April 2015. Outcomes: most of the teenagers were females ones, aged 13-14 years. Most of their families were dysfunctional. From the studied barriers for healthy behaviour, the one with more incidences was the intake of food sold near the school with 95.3 %. Conclusions: in spite of these results, 60.7 % of the permanent molars were healthy (AU).

Estado del primer molar permanente en niños de 6 a 11 años de edad / Status of the first permanent molar in children aged 6 to 11 years

Introducción: los primeros molares permanentes son considerados dientes pilares fundamentales en la cavidad bucal, su pérdida precoz causa un daño irreparable, dado su papel como llave de la oclusión dentaria. Objetivo: evaluar el estado de salud del primer molar permanente. Materiales y métodos: se realizó una investigación observacional, descriptiva y transversal en la Escuela Primaria “Raúl Gómez García,” perteneciente al área de salud de Milanés de la Clínica “III Congreso del PCC,” del municipio de Matanzas, en el período del curso académico 2013 - 2014. De un universo de 382 niños que constituían la matrícula total de la escuela, se seleccionaron mediante un muestreo aleatorio simple, una muestra de 298, de la edad de 6 a 11 años, que tenían presente en boca los cuatro primeros molares permanentes en el momento del examen. Se estudiaron variables como: edad, sexo, superficies afectadas del primer molar permanente, estado del primer molar permanente, afectación del paciente, e Índice epidemiológico de Clune. Los datos fueron registrados en tablas y el procedimiento estadístico dado en porcentaje. Se contó con el consentimiento de la dirección de la escuela y de los padres de los niños. Resultados: las superficies o caras de los molares más afectados fueron las oclusales tanto por caries (36,5 %), como obturadas (28,1 %). Del total de la muestra, 208 niños presentaron sus cuatro primeros molares libres de caries, para un 69,8 %. Solo 1 niño fue clasificado de grave, para un 1,8 %. Conclusiones: un elevado número de niños presentaron sus primeros molares libres de caries dental y pocos la pérdida del primer molar permanente.

Background: the first permanent molars are considered main pillar teeth in the oral cavity. Their precocious lost causes an irreparable damage, given their role as the key of the dental occlusion. Aim: to evaluate the first permanent molar health status. Materials and methods: a cross-sectional, descriptive, observational research was carried out in the Primary School “Raul Gómez García,” belonging to Milanes health area of the Clinic “III Congreso del PCC,” municipality of Matanzas, in the period of the school year 2013- 2014. From the universe of 382 children matriculated in the school, via simple randomized screening, there they were chosen 298 children who had in their mouth the four first permanent molars at the moment of the examination. The studied variables were age, gender, damaged surfaces of the first permanent molar, status of the first permanent molar, patients’ affectation, and Clune´s epidemiologic index. Data were registered in charts and the statistical procedure was given in percentages. The informed consent was given by parents and the managing staff of the school. Outcomes: the most damaged molar surfaces or sides were the occlusal ones because of caries (36.5 %) and because of obturations (28.1 %). From the total of the sample, 208 children had their four first molars free of caries, for 69.8 %. Only 1 child was classified as seriously ill, for 1.8 %. Conclusions: a high number of children had their first molars free of dental caries and few of them had lost their first permanent molar.

Caries dental en los primeros molares permanentes en escolares / Dental caries in the first permanent molars in school children

Introducción: en la edad escolar el diente permanente más afectado por caries dental es el primer molar permanente, y la prevalencia de caries en ellos se asocia con actividad futura de caries. Por erupcionar sin haber exfoliado ningún elemento primario, las madres, desconocen que este es un diente permanente. Su destrucción parcial o total repercute en el desarrollo y crecimiento maxilofacial y la oclusión. Objetivos: describir la afectación por caries dental en los primeros molares permanentes en escolares, así como el conocimiento de la madre sobre estos. Materiales y métodos: se realizó un estudio observacional, descriptivo y transversal en la Escuela Primaria Máximo Gómez, de Alamar, en febrero de 2013. A 211 escolares se le efectuó examen bucal, registrándose los primeros molares sanos, cariados, restaurados y perdidos. Se entrevistaron a las madres para saber sobre su conocimiento del primer molar permanente. Resultados: el 40,3 % tuvo al menos un primer molar permanente afectado. La frecuencia fue, en masculino, 50,6 %, y en la edad de 11 años, 28,2 %. El índice dental cariado obstruido perdido fue en el 26 y 46, de promedio 0,81 y 81 %, respectivamente. El desconocimiento de las madres fue del 64,3 % del total. Conclusiones: casi la mitad de la muestra presenta al menos un primer molar permanente afectado por caries dental y la edad de 11 años es la más frecuente. No se señalan diferencias en cuanto al sexo. La experiencia mayor de caries dental la presentan los molares 46 y 26. La mayoría de las madres no tiene conocimientos acerca del primer molar permanente.

Background: in school age, the tooth most affected by dental caries is the first permanent molar, and the caries prevalence in them is associated to the future caries activity. Due to its eruption without the exfoliation of primary elements, mothers do not know that this is a permanent tooth. Its partial or total destruction affects the maxillofacial growth and development and leads to malocclusion. Aims: describing the damage due to dental caries in the first permanent molars in school children, and also their mothers’ knowledge on them. Material and methods: we carried out a cross-sectional, descriptive, observational study in the Primary School Maximo Gómez, of Alamar, in February 2013. Buccal exam was made to 211 schoolchildren, recording the healthy, carious, restored and lost first permanent molars. Mothers were interviewed to identify their knowledge on the first permanent molar. Results: 40,3 % of the sample had at least one permanent molar damaged. The frequency was, in male schoolchildren, 50,6 %, and at the age of 11 years, 28,2 %. The carious-obstructed-lost dental index in the 26 and 46 teeth was an average of 0,81 and 81 % respectively. Mothers’ lack of knowledge was 64,3 % of the total. Conclusions: almost half of the sample had at least one permanent molar damaged by dental caries and the most frequent age is 11 years. There are not differences according to de gender. The highest existence of dental caries is in 26 and 46 molars. Most of the mothers do not know about the first permanent molar.

Pérdida del primer molar permanente en niños de 6-12 años de edad. Colón. 2013 / First permanent molar lost in children aged 6-12 years. Colon. 2013

El primer molar permanente es una de las estructuras dentarias más importantes para el desarrollo de una oclusión fisiológica y una adecuada función masticatoria, estos dientes desempeñan un papel primordial en el desarrollo y mantenimiento de una oclusión dentaria apropiada, son muy susceptibles a la caries dental, después de su erupción, alrededor de los 6 años. Se realizó un estudio observacional, descriptivo, transversal en la escuela René Fraga Moreno del municipio Colón, provincia de Matanzas con el objetivo de determinar la pérdida del primer molar permanente en los niños de 6 a 12 años, en el periodo comprendido de noviembre del 2012 a enero del 2013. El universo fue 395 estudiantes comprendidos en las edades 6-12 años, la muestra la conformaron 41 niños con,al menos, la pérdida de uno de los cuatro primeros molares. Como resultado, prevalecieron los de 12 años, con los primeros molares ausentes, representando el 31.7 %; el sexo masculino fue el más representado con 65,8 %, el grupo de edad de 12 años presentó un 61.5 % de estudiantes con higiene bucal inadecuada. Se observó que un 87.8 % de los estudiantes estudiados consumían dieta cariogénica, el primer molar que más ausente se encontró en la boca de estos niños fue el primer molar inferior derecho con 60.9 %. Esta afección afectó más al sexo masculino. Predominó la higiene bucal inadecuada. En todas las edades prevaleció la dieta cariogénica. El primer molar inferior derecho fue el que más se ausentó en la boca de estos niños.

The first permanent molar is one of the most important dental structures for the development of a physiologic occlusion and an adequate masticatory function; these teeth play an important role in the development and maintenance of an appropriate dental occlusion; they are very predisposed to dental caries after their eruption, around the age of 6 years. A cross-sectional, descriptive, observational study was carried out in the school Rene Fraga Moreno, of Colon municipality, province of Matanzas, with the aim of determining the first permanent molar lost in children aged 6-12 years, in the period from November 2012 to January 2013. The universe were 395 schoolchildren aged 6-12 years; the sample was composed by 41 children, with at least the lost of one of the four first molars. As a result there it was the prevalence of children aged 12 years, with the absence of the first molars, representing 31, 7 %; the male gender was the most represented one with 65, 8 %, and the 12 years age group presented 61, 5 % of students with inadequate buccal hygiene. We observed that 87, 8 % of the studied schoolchildren had a cariogenic diet; the more frequently absent first molar was the first right low molar with 60. 9 %. The male gender was the most affected by this disorder. The inadequate buccal hygiene predominated. The cariogenic diet prevailed in all ages. The first right low molar was the most frequently found lost in the mouth of these children.

Problem of protect 6th permanent molar / Шинэ санаа Шинэ нээлт

The age of 12 permanent molars 6 source formation, teeth grow footnote rows of teeth to catch various dental routine dental transferred under the grip. Operations and development perspective 6th gear teeth with dental row a key role to ensure a balance between teeth. This is the dental caries and other reasons deviations in adjacent teeth, jaw bones flaw, merge lengthen teeth, chewing on a toothpick footnote central line switch the arc fault is the key basic conditions.We study in MNUMS Dental school 2013-2014 customers in 1:1 ratio unfolded taken x-ray studied biological life in a sample of pictures of children over the age of 12 . Picture Image J 1.49b measurement statistics into the application development with SPSS 17.0.Biological age of 12 years old 6th gear teeth grow reach during our study involved 56 children , 18 ( 32.14 %) were taken in 6th gear teeth .Therefore, the 6th gear to be controlled from the start grow regular dental caries prevention laces jaw bone and teeth abnormalities shows the importance of the development.