Comparative analysis of the effect of Bioactive Glass 45S5 on enamel erosion progression in human dentitions (in vitro study).

OBJECTIVES: The aim of the present study was to compare the surface morphology alterations, mineral content, and surface roughness of eroded enamel surface versus eroded enamel surface which was preceded by Bioactive Glass 45S5 (BAG45S5) application in both primary and permanent human dentitions. MATERIALS AND METHODS: Fifty-two primary teeth and fifty-two permanent teeth were selected. Teeth were randomly divided into 4 groups of twenty-six teeth each. Groups A1 and B1 underwent erosion with 1% citric acid, while groups A2 and B2 were subjected to application of BAG45S5 powder followed by the same erosive conditions as A1 and B1. Measurements were performed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and surface profilometry. They were used to examine the surface morphology alterations, mineral content, and surface roughness, respectively. RESULTS: SEM of enamel which received BAG45S5 showed smoother surface in primary teeth post erosion. EDX analysis showed that enamel exhibited crucial resistance to mineral loss in the group which received BAG45S5 prior to inducing erosion as compared to the induced erosion-only group. This was significant (p < 0.005) in both human dentitions. Erosion-only groups showed significantly less surface roughness in permanent teeth (p < 0.045). A marked decrease in surface roughness was observed in surfaces receiving BAG45S5, primary teeth (p < 0.001), and permanent teeth (p < 0.001). CONCLUSIONS: Bioactive Glass 45S5 proved successful against erosive conditions in both primary and permanent teeth with better performance in the permanent teeth so it can be regarded as a means of prevention. CLINICAL RELEVANCE: Bioactive Glass 45S5 powder could be used not only to remove stains but also as a prophylactic preventive measure against the multiple episodes of acidic food and beverage consumption in children.

Diverse stem-chondrichthyan oral structures and evidence for an independently acquired acanthodid dentition.

The teeth of sharks famously form a series of transversely organized files with a conveyor-belt replacement that are borne directly on the jaw cartilages, in contrast to the dermal plate-borne dentition of bony fishes that undergoes site-specific replacement. A major obstacle in understanding how this system evolved is the poorly understood relationships of the earliest chondrichthyans and the profusion of morphologically and terminologically diverse bones, cartilages, splints and whorls that they possess. Here, we use tomographic methods to investigate mandibular structures in several early branching 'acanthodian'-grade stem-chondrichthyans. We show that the dentigerous jaw bones of disparate genera of ischnacanthids are united by a common construction, being growing bones with non-shedding dentition. Mandibular splints, which support the ventro-lateral edge of the Meckel's cartilage in some taxa, are formed from dermal bone and may be an acanthodid synapomorphy. We demonstrate that the teeth of Acanthodopsis are borne directly on the mandibular cartilage and that this taxon is deeply nested within an edentulous radiation, representing an unexpected independent origin of teeth. Many or even all of the range of unusual oral structures may be apomorphic, but they should nonetheless be considered when building hypotheses of tooth and jaw evolution, both in chondrichthyans and more broadly.

Evaluation of Lower Dental Arch Crowding and Dimension after Treatment with Lip Bumper versus Schwarz Appliance. A Prospective Pilot Study.

Aim: The treatment of patients with mixed dentition, with inferior moderate dental crowding (the so-called borderline cases, between extraction and expansion) is not yet clear. Two examples of widely used appliances for increasing lower dental arch dimensions are the Schwarz's appliance and lip bumper. The aim of this prospective study was to compare dental crowding and arch dimensions from pre- to post-treatment with lip bumper versus Schwarz's appliance. Subjects and Methods: Pre- and post-treatment orthodontic records of twenty subjects (10 males and 10 females) were analyzed in the present study. Inclusion criteria were: first/second molar class malocclusion; crowding of the mandibular arch, from mild to moderate (4-6 mm); mixed dentition; age ≤ 9 years at the beginning of the treatment; stage CS1 or CS2 of maturation of the cervical vertebrae analysis (CVM) at the beginning of the treatment. Ten subjects were treated with a lip bumper, and ten with the removable Schwarz appliance. The primary outcomes were the variations in dental crowding and arch dimensions from pre- to post-treatment. Results: Both the two appliances caused a statistically significant mean improvement/reduction in crowding, of 3.5 mm and 2.9 mm, for the Schwarz appliance and lip bumper, respectively. The Schwarz appliance resulted more effective in increasing arch dimension at the intercanine level, and arch perimeter, while the lip bumper achieves a higher increase in arch length. Conclusions: A lip bumper and Schwarz appliance are both useful in reducing crowding in mixed dentition. This improvement is due to the increase in dental arch dimensions, although the distribution of space resulted slightly differently between the two appliances.

Food avoidance is associated with reduced dentitions and edentulousness.

OBJECTIVES: To investigate associations between food avoidance and dental status, age, gender, and socio-economic status (SES). MATERIALS AND METHODS: The Chinese sample comprised 1463 dentulous (≥ 1 tooth in each jaw) and 124 edentulous (in one or both jaws) participants aged ≥ 40 yrs. The Vietnamese sample comprised 2820 dentulous and 253 edentulous participants aged ≥ 20 yrs. Food avoidance due to chewing difficulties was scored for regionally common 4 soft and 4 hard foods. Dental status was classified according to the multi-level hierarchical dental functional classification system (HDFC) based on the number and location of teeth and posterior occlusal pairs. Associations were analyzed using multivariate logistic regression analyses. RESULTS: For dentulous participants, the chance of avoiding foods was significantly larger with < 10 teeth in each jaw (OR = 2.26 (Chinese sample), respectively 1.74 (Vietnamese sample)), incomplete anterior region (OR = 1.78, respectively 1.84), "impaired" premolar region (OR = 2.22, respectively 1.71), or "impaired" molar region (OR = 2.46, respectively 1.84). Edentulous participants had twice the chance of avoiding foods (OR = 2.01 respectively 2.20). Avoiding foods was significantly associated with higher age. Participants of low SES (Chinese sample, OR = 1.93) and females (Vietnamese sample, OR = 1.27) had a larger chance of avoiding foods. CONCLUSIONS: Avoiding foods was significantly associated with reduced dentitions, edentulousness, and higher age; low SES only in the Chinese and being female only in the Vietnamese sample. CLINICAL RELEVANCE: Incomplete anterior regions, "impaired" premolar or molar regions, and especially edentulousness can be considered significant risk indicators for food avoidance.

Clinical laboratory analysis of maximum intercuspation registration results in patients with intact dentitions.

OBJECTIVE: Introduction: In modern dental prosthetic practice, there often occur inconsistencies of occlusion in oral cavity and on cast dental models, leading to search for a solution to the problem of improving the registration accuracy of occlusal relationships of dentitions. The aim: Clinical laboratory study of bite registration materials selected efficiency. PATIENTS AND METHODS: Materials and methods: Examination of 10 patients was conducted. Registration biomaterials: Consiflex, Аluwaх, Futar D were successively placed on occlusal surfaces of each patient. After polymerization of registration materials, determination of biometric deviation of markers from complementary position in the regions of dentitions under study was performed. Clinical measurements of BDM values were performed with an accuracy of ±0,01 mm. RESULTS: Results: During clinical examination using Futar D, BDM index in the region of teeth 16-46 reached (0,055±0,05) mm, 26-36 - (0,065±0,05) mm, 13-44 - (0,075±0,04) mm, 23-34 - (0,075±0,06) mm, 21-31 - (0,015±0,02) mm. In case of using aluwax, BDM index in teeth 16-46 was (0,075±0,04) mm, 26-36 - (0,11±0,07) mm, 13-44 - (0,08±0,04) mm, 23-34 - (0,09±0,07) mm, 21-31 - (0,02±0,03) mm. Application of Consiflex demonstrated BDM index in teeth 16-46 was (0,075±0,06) mm, 26-36 - (0,11±0,07) mm, 13-44 - (0,13±0,06) mm, 23-34 - (0,14±0,07) mm,21-31 - (0,045±0,04) mm. CONCLUSION: Conclusions: Clinical and laboratory research with the use of Futar D registration materials in patients with intact dentitions demonstrated lower optimum of differences between BDM indices in comparison with Consiflex and Aluwax.

Dental age estimation methods in adult dentitions: An overview.

Age estimation is one of the essential factors in human identification. Teeth bestowed with features such as hardness and resilience to external factors such as chemicals, putrefaction, and fire explosions serve as a durable source in age estimation. Concurrently, they present with peculiar and comparable features of age-associated regressive changes along with dental procedures, which make them a mirror reflection of age changes from cradle to the grave of an individual. Age estimation in adults poses an enigma to the forensic dentists because as the age advances, the dentitions get influenced by numerous exogenous and endogenous factors which may lead to discrepancies between dental age and chronologic age. Since 1950, many authors have presented various methods for assessing age of individuals above 18 years. Here is an overview of the different methods with their application and limitations along with a mention of newer methods developed and tested with the formulation of population-specific formulas by Indian authors. The data have been sourced from different journal articles retrieved through Google Scholar and PubMed Central and articles received as study materials during the fellowship program in forensic odontology using keywords such as age estimation, adult dentitions, dentin translucency, and cementum annulations.

Development and evolution of tooth renewal in neoselachian sharks as a model for transformation in chondrichthyan dentitions.

A defining feature of dentitions in modern sharks and rays is the regulated pattern order that generates multiple replacement teeth. These are arranged in labio-lingual files of replacement teeth that form in sequential time order both along the jaw and within successively initiated teeth in a deep dental lamina. Two distinct adult dentitions have been described: alternate, in which timing of new teeth alternates between two adjacent files, each erupting separately, and the other arranged as single files, where teeth of each file are timed to erupt together, in some taxa facilitating similarly timed teeth to join to form a cutting blade. Both are dependent on spatiotemporally regulated formation of new teeth. The adult Angel shark Squatina (Squalomorphii) exemplifies a single file dentition, but we obtained new data on the developmental order of teeth in the files of Squatina embryos, showing alternate timing of tooth initiation. This was based on micro-CT scans revealing that the earliest mineralised teeth at the jaw margin and their replacements in file pairs (odd and even jaw positions) alternate in their initiation timing. Along with Squatina, new observations from other squalomorphs such as Hexanchus and Chlamydoselachus, together with representatives of the sister group Galeomorphii, have established that the alternate tooth pattern (initiation time and replacement order) characterises the embryonic dentition of extant sharks; however, this can change in adults. These character states were plotted onto a recent phylogeny, demonstrating that the Squalomorphii show considerable plasticity of dental development. We propose a developmental-evolutionary model to allow change from the alternate to a single file alignment of replacement teeth. This establishes new dental morphologies in adult sharks from inherited alternate order.

Estudo preliminar in vivo da magnitude de força gerada na expansão rápida da maxila (ERM) / An in vivo preliminary study of force magnitude generated in rapid maxillary expansion (RME)

A expansão rápida da maxila (ERM) sempre despertou grande interesse nos pesquisadores da área da Ortodontia e Ortopedia facial ao longo dos anos por ser um dos procedimentos mais empregados na especialidade. Além disso, as atresias maxilares desenvolvem-se de uma maneira precoce sem autocorreção espontânea. A magnitude de força expansiva e suas implicações durante o procedimento clínico de ERM permanecem questionáveis até hoje. O presente estudo tem como objetivo avaliar a magnitude e o comportamento da força expansiva durante a ERM nas fases das dentições mista e permanente jovem. Esta amostra inicial foi composta por 4 pacientes brasileiros, do gênero feminino, e que foram separados em dois grupos de acordo com suas fases de dentição: Grupo I, composto de dois pacientes com dentição mista e Grupo II composto de dois pacientes com dentição permanente jovem. O aparelho utilizado no estudo foi um disjuntor palatino do tipo McNamara. O protocolo de ativação foi de duas ativações diárias. Os resultados obtidos permitem concluir que o comportamento das forças expansivas ao longo do procedimento variou longitudinalmente, individualmente e entre os grupos experimentais. Observa-se ainda que a força máxima expansiva mensurada no Grupo I foi de 65N e no Grupo II de 78N.

Rapid maxillary expansion (RME) is a largely employed procedure and therefore it has always aroused great interest of researchers in the Orthodontic and facial Orthopedics fields. In addition, maxillary constrictions have an early development and are hardly self corrected. The aim of this preliminary study was to assess the magnitude and behavior of the expansive force during RME in mixed and young permanent dentition. The sample consisted of 4 Brazilian female patients, who were sorted in two groups: Group I, two patients with mixed dentition and Group II, two patients, with young permanent dentition. The appliance utilized in this study was a McNamara palatal distractor. The activation protocol included two daily activations. Results acquired allow for the conclusion that the behavior of expanding forces along the procedure has varied in longitudinal manner, individually and between the experimental groups. And they have also determined that the maximum expanding force measured in Group I was 65N, and in the Group II it was 78N.

Association between maximum bite force and craniofacial morphology in an Amazonian population with normal dental occlusion / Associação entre força máxima de mordida e morfologia craniofacial em população Amazonense com oclusão normal

The aim of this study was to determine the maximum bite force (MBF) in Amazonian children and young adolescents with normal dental occlusion, the average craniofacial morphology, and investigate associations between craniofacial morphology and body mass with MBF. Ninety-seven children and young adolescents, 21 with primary dentition and 76 with permanent dentition and normal dental occlusion were included in the study. Subjects were from Amazonian tribes studying at three schools in Leticia, Amazonas, Colombia. MBF was determined by means of a digital hydraulic pressure gauge. Body mass index (BMI), facial morphology index, and dental arches transverse dimensions were computed in each subject. Mann Whitney test, a one-tailed non-parametric statistical analysis, was used to contrast MBF between primary dentition and permanent dentition. The same statistical analysis was used to determine MBF statistical differences between the various facial morphologies. Pearson correlation statistical analysis was used to evaluate associations between MBF with BMI, dental arches transverse dimensions or facial morphology. Statistical significance was determined at 95 percent level of confidence. A significant difference was found for the MBF between subjects in primary dentition (incisors: 116.57 ± 48.30; right molars: 368.38 ± 105.52; left molars: 322.76 ± 83.77) and those in permanent dentition (incisors: 260.88 ± 85.73; right molars: 459.63 ± 167.11; left molars: 645.67 ± 170.60). In addition, an association was observed between MBF and facial morphology index. It was concluded that MBF significantly increases from primary to permanent dentition in subjects with normal dental occlusion. Furthermore, this study agrees with other reports stating that MBF is associated with the morphology of the face, but not with BMI or dental arches transverse dimensions.

O presente estudo teve como objetivo determinar a força máxima de mordida (FMM) e morfologia craniofacial média de crianças e adolescentes da região do Amazonas com oclusão dentária normal, e investigar associações entre índice de massa corpórea (IMC), morfologia craniofacial e FMM. Participaram do estudo 97 crianças e adolescentes, 21 deles com dentição primária e 76 com dentição permanente, todos com oclusão dentária normal. Os indivíduos pertencentes a tribos amazônicas estudavam em três escolas em Leticia, Amazonas e Colombia. A FMM foi determinada utilizando medidor de pressão hidráulica digital. Índice de massa corporal (IMC), índice morfológico, e dimensões transversais dos arcos dentários de cada indivíduo foram registrados. O teste de Mann Whitney, análise unicaudal não paramétrica, foi aplicado na comparação da força máxima de mordida em dentição decídua e permanente. A mesma análise estatística foi utilizada para determinar as diferenças estatísticas acerca da FMM entre as diferentes características da morfologia facial. O coeficiente de correlação de Pearson foi empregado para avaliar as associações entre FMM e IMC, dimensão transversal dos arcos dentários ou morfologia facial. A significância estatística foi determinada com intervalos de 95% de confiança. Diferença significativa foi observada para FMM entre sujeitos com dentição decídua (incisivos: 116.57 ± 48.30; molares direitos: 368.38 ± 105.52; molares esquerdos: 322.76 ± 83.77) e aqueles com dentição permanente (incisivos: 260.88 ± 85.73; molares direitos: 459.63 ± 167.11molares esquerdos: 645.67 ± 170.60).