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Abstract Objective: Considering that the available studies on prevalence of malocclusions are local or national-based, this study aimed to pool data to determine the distribution of malocclusion traits worldwide in mixed and permanent dentitions. Methods: An electronic search was conducted using PubMed, Embase and Google Scholar search engines, to retrieve data on malocclusion prevalence for both mixed and permanent dentitions, up to December 2016. Results: Out of 2,977 retrieved studies, 53 were included. In permanent dentition, the global distributions of Class I, Class II, and Class III malocclusion were 74.7% [31 - 97%], 19.56% [2 - 63%] and 5.93% [1 - 20%], respectively. In mixed dentition, the distributions of these malocclusions were 73% [40 - 96%], 23% [2 - 58%] and 4% [0.7 - 13%]. Regarding vertical malocclusions, the observed deep overbite and open bite were 21.98% and 4.93%, respectively. Posterior crossbite affected 9.39% of the sample. Africans showed the highest prevalence of Class I and open bite in permanent dentition (89% and 8%, respectively), and in mixed dentition (93% and 10%, respectively), while Caucasians showed the highest prevalence of Class II in permanent dentition (23%) and mixed dentition (26%). Class III malocclusion in mixed dentition was highly prevalent among Mongoloids. Conclusion: Worldwide, in mixed and permanent dentitions, Angle Class I malocclusion is more prevalent than Class II, specifically among Africans; the least prevalent was Class III, although higher among Mongoloids in mixed dentition. In vertical dimension, open bite was highest among Mongoloids in mixed dentition. Posterior crossbite was more prevalent in permanent dentition in Europe. Resumo Objetivo: considerando-se que os estudos disponíveis sobre a prevalência das más oclusões são de base local ou nacional, esse estudo teve como objetivo reunir dados para determinar a distribuição dos tipos de má oclusão em uma escala global, nas dentições permanente e mista. Métodos: foi realizada uma busca eletrônica através das ferramentas de pesquisa do PubMed, Embase e Google Acadêmico, para reunir estudos publicados até dezembro de 2016 sobre a prevalência das más oclusões, tanto na dentição permanente quanto na dentição mista. Resultados: dos 2.977 estudos encontrados, 53 foram analisados. Na dentição permanente, a distribuição mundial das más oclusões de Classe I, II e III foi, respectivamente, de 74,7% [31 - 97%], 19,56% [2 - 63%] e 5,93% [1 - 20%]. Na dentição mista, a distribuição dessas más oclusões foi de 73% [40 - 96%], 23% [2 - 58%] e 4% [0,7 - 13%]. Em relação às más oclusões verticais, observou-se prevalência de 21,98% de sobremordida profunda e 4,93% de mordida aberta. A mordida cruzada posterior afetou 9,39% da amostra. Os africanos mostraram a maior prevalência de Classe I e mordida aberta na dentição permanente (89% e 8%, respectivamente) e na dentição mista (93% e 10% respectivamente), enquanto os caucasianos apresentaram a maior prevalência de Classe II na dentição permanente (23%) e na dentição mista (26%). A má oclusão de Classe III na dentição mista foi mais prevalente entre xantodermas. Conclusão: mundialmente, nas dentições mista e permanente, as más oclusões de Classe I de Angle são mais prevalentes do que as de Classe II, especificamente entre os africanos; a menos prevalente foi a Classe III, ainda que mais prevalente entre os xantodermas na dentição mista. Na dimensão vertical, as mordidas abertas foram mais prevalentes entre xantodermas na dentição mista. A mordida cruzada posterior apresentou maior prevalência na dentição permanente na Europa.

Background The development of primary dentition can be affected by oral sucking habits. Therefore, this study aims to investigate the association of nutritive and non-nutritive sucking habits with primary dentition development. Methods One thousand one hundred and fourteen children aged 2 to 5 years old in Hong Kong were recruited in a cross-sectional study. Information on their nutritive (e.g. breastfeeding and bottle feeding) and non-nutritive sucking habits (e.g. pacifier use and thumb/digit sucking) was collected via questionnaires. The children’s primary occlusions were examined in three dimensions. Results Children who were breastfed for more than 6 months had a lower proportion of daily pacifier use ( p  < 0.05). Children who used pacifiers daily had a higher proportion of thumb/digit sucking ( p  < 0.05). Children who used pacifiers daily for more than one year had higher chances of developing an anterior open bite ( p  < 0.05) and a reduced overbite ( p  < 0.05). Those exhibiting daily thumb/digit sucking for more than one year had higher chances of developing Class II incisor and Class II canine relationships, an increased overjet and anterior open bite ( p  < 0.05). Conclusion Pure breastfeeding for more than 6 months is inversely associated with daily pacifier use and daily pacifier use is positively associated with daily thumb/digit sucking. Children with more than one year of daily pacifier use and thumb/digit sucking have higher chances of developing abnormal dental relationships in the sagittal (i.e. Class II incisor and Class II canine relationships and increased overjet) and vertical (i.e. anterior open bite) dimensions, respectively.

Objective This study aimed to assess the occlusal contact area (OCA), occlusal contact number (OCN), bite force, and artificial tooth wear in complete dentures with lingualized and bilateral balanced occlusion. Methods Edentulous participants who fulfilled the inclusion criteria were divided into the three groups as follows: group I, dentures with lingualized occlusion using interpenetrating polymer network artificial teeth; group II, dentures with lingualized occlusion using double cross-linked artificial teeth; and group III, dentures with bilateral balanced occlusion using anatomical micro-hybrid resin teeth. The silicone techniques were used to assess the OCA and OCN of the mandibular dentures and the Dental Prescale II was used to evaluate the bite force at the 2-week, 3-month, and 12-month follow-up visits. Occlusal contact analyzer software was used to assess the maxillary and mandibular posterior tooth wear at the 12-month follow-up visit. All data was analyzed using the SPSS software. Results The OCA of group III was significantly higher than that of groups I and II at the 2-week follow-up visit, whereas group I was considerably higher than groups II and III at the 3-month and 12-month follow-up visits. The OCN of the three groups exhibited significant differences at all three follow-up visits. Groups I and II had significantly lower bite force than Group III at the three follow-up visits. At the 12-month follow-up visit, groups I and II had significantly higher wear than Group III. Conclusions As the duration of use increases, the occlusal contact area of complete dentures increases, regardless of the occlusal schemes. The bite force of lingualized occlusion is typically lower than that of bilateral balanced occlusion. The wear locations of artificial teeth differ between the two types of occlusal schemes. (Retrospectively registered: The Chinese Clinical Trial Registry, No. ChiCTR2300073420(11/07/2023))

The study in the field of periodontics and etiology focuses on the crucial task of classifying occlusion classes in dentition through the application of deep learning algorithms. The occlusion patterns between upper and lower jaws play a pivotal role in understanding and treating dental conditions such as periodontitis, Pierre Robin syndrome, and maxilla fractures.The extent of asymmetrical overlap between the upper and lower jaw forms various classes of occlusion. Hence, the classification of occlusion becomes an essential prerequisite for the successful treatment of many dentistry related diseases like oral cancer, gingival recession, and tooth erosion.The research employed a dataset comprising 200 dental images extracted from Stereolithography (STL) files using an Intraoral scanner, presenting 2D representations of dental structures. Various deep learning architectures, including LeNet, AlexNet, Inception, and DenseNet, were utilized for the classification task. The Inception model emerged as the most accurate, achieving an 84.39% accuracy rate due to its non-sequential architecture, followed closely by DenseNet at 84.10%, LeNet at 82.39%, and AlexNet at 78.43%. Therefore, these accuracy results indicated a relative trend as Inception > DenseNet > LeNet > AlexNet.The study suggests the potential application of the automated classification system, particularly based on the Inception model, by clinicians due to its high accuracy, effectiveness, and efficiency in processing time. This technological advancement holds promise for significantly contributing to treatment planning and surgeries in dental practice.

Background and objectives: This study analyzed and compared the distribution patterns of occlusal forces using T-Scan III before and after the hydrostatic temporary oral splint (Aqualizer Ultra) therapy in healthy subjects and subjects with temporomandibular disorders (TMDs). Materials and Methods: Fifty-one subjects were divided into groups based on anamnesis and responses to the Fonseca questionnaire. The first group, non-TMDs group (n = 19), and the second group, TMDs group (n = 32), had mild-to-severe TMDs, as identified by the Fonseca questionnaire. The non-TMDs group had an average age of 25.4 years (SD = 4.8, range 20–38) with 15 females (78.95%) and 4 males (21.05%). The TMDs group had an average age of 27.4 years (SD = 7.0, range 22–53) with 25 females (78.125%) and 7 males (21.875%). T-Scan III device was used for occlusal analysis before and after hydrostatic splint usage. Results: Significant differences were observed in the TMDs group for anterior and posterior right percentages of forces before and after hydrostatic splint usage. The analysis of force distribution per sector before and after hydrostatic splint therapy showed no significant differences in the non-TMDs group. Analysis of force distributions in the entire study population before and after hydrostatic splint therapy showed significant differences in the anterior and posterior right regions. Occlusal force increased by 32–56% in the front region and decreased in the posterior area after hydrostatic splint usage. Conclusions: Hydrostatic splint therapy is recommended as a part of full-mouth rehabilitation treatment for all patients regardless of the severity of TMDs.

ObjectivesThe benefit from positioning the maxillary casts with the aid of face-bows has been questioned in the past. Therefore, the aim of this study was to investigate the reliability and validity of arbitrary face-bow transfers compared to a process solely based on the orientation by means of average values. For optimized validity, the study was conducted using a controlled, randomized, anonymized, and blinded patient simulator study design.Material and methodsThirty-eight undergraduate dental students were randomly divided into two groups; both groups were applied to both methods, in opposite sequences. Investigated methods were the transfer of casts using an arbitrary face-bow in comparison to the transfer using average values based on Bonwill’s triangle and the Balkwill angle. The “patient” used in this study was a patient simulator. All casts were transferred to the same individual articulator, and all the transferred casts were made using type IV special hard stone plaster; for the attachment into the articulator, type II plaster was used. A blinded evaluation was performed based on three-dimensional measurements of three reference points.ResultsThe results are presented three-dimensionally in scatterplots. Statistical analysis indicated a significantly smaller variance (Student’s t test, p < 0.05) for the transfer using a face-bow, applicable for all three reference points.ConclusionsThe use of an arbitrary face-bow significantly improves the transfer reliability and hence the validity.Clinical relevanceTo simulate the patient situation in an individual articulator correctly, casts should be transferred at least by means of an arbitrary face-bow.

Osteonecrosis of the jaw (ONJ) is a serious adverse event that is associated with antiresorptive agents, and it manifests as bone exposure in the maxillofacial region. Previous clinical reports suggest that mechanical trauma would trigger ONJ in a manner that is similar to tooth extractions. To the best of our knowledge, there have been few detailed pathophysiological investigations of the mechanisms by which occlusal/mechanical trauma influences ONJ. Here, we developed a novel mouse model that exhibits ONJ following experimental hyperocclusion and nitrogen-containing bisphosphonate (N-BP) treatment. This in vivo model exhibited ONJ in alveolar bone, particularly in the mandible. Moreover, the experimental hyperocclusion induced remarkable alveolar bone resorption in both mouse mandible and maxilla, whereas N-BP treatment completely prevented alveolar bone resorption. In this study, we also modeled trauma by exposing clumps of mesenchymal stem cells (MSCs)/extracellular matrix complex to hydrostatic pressure in combination with N-BP. Hydrostatic pressure loading induced lactate dehydrogenase (LDH) release by calcified cell clumps that were differentiated from MSCs; this LDH release was enhanced by N-BP priming. These in vivo and in vitro models may contribute further insights into the effect of excessive mechanical loading on ONJ onset in patients with occlusal trauma.

Background: Available knowledge about malocclusion and cephalometric variables and their connection with an increased risk of condylar displacement (CD) is scarce. This article aims to present current information on the relationship between centric relation-maximum intercuspal position discrepancies and maxillofacial morphology and malocclusion in patients seeking orthodontic treatment as well as to identify those who require expanded diagnostic evaluation for this disorder. Methods: This review analyzed the PubMed, Cochrane Library, Web of Science, and Scopus electronic databases up to February 2022. Keywords and additional manual searches were performed. Literature selection was based the PRISMA-ScR checklist. The JBI Critical Appraisal Tool assessed the methodological quality of included studies. Results: The databases search provided 2321 studies. A total of 10 studies were included in this review after eligibility criteria and JBI assessment. This review was separated into five parts that evaluated CD correlations depending on the following: maxillofacial structure in different vertical and sagittal skeletal patterns, vertical, horizontal, and transverse malocclusions. Conclusions: A hyperdivergent facial skeletal structure is a risk factor for increased CD, particularly in the vertical dimension. The condylar processes are usually displaced in a posteroinferior direction. Further studies are warranted to elucidate the relationship among remaining skeletal and dental malocclusions and the occurrence of CD.

Tongue function is regarded as a primary factor in the etiology of malocclusion, but details of the relationship remain unknown. The purpose of the present study was to investigate maximum tongue pressure, in preschool children to examine its relationship with dental occlusion. A total of 477 healthy children (248 boys, 229 girls, aged 4–6 years) were recruited. Dental occlusion was assessed visually to record sagittal, vertical, and transverse malocclusion, and space discrepancies. Maximum tongue pressure was measured using a balloon-based tongue pressure measurement device. Additionally, 72 children (37 boys, 35 girls, aged 4–5 years) were recruited for a 1-year follow-up study. Approximately half of the children (53.5%) showed some type of malocclusion in the present study. Maximum tongue pressure was highest in the 6-year-old children. The results of a two-way ANCOVA show that the effect of age was significant (p < 0.001); however, the effects of sex and dental occlusion, or the interactions among these variables, did not reach significance. Additionally, maximum tongue pressure increased significantly in the 1-year follow-up study (p < 0.001), especially in the normal occlusion group. Maximum tongue pressure increases markedly with growth in the preschool years and can be associated with some types of malocclusion in preschool children.