Effect of LED photobiomodulation on dental implant osseointegration: An in vivo study.

Background: Photobiomodulation (PBM) may be prescribed after dental surgery to accelerate tissue healing and improve implant stability. The objective of this study is to evaluate the efficiency of LED-PBM on the dental implant osseointegration. Methods: A total of 48 implants (KontactTM) were inserted in 8 Yucatan minipigs (6 implants per minipig) divided into 2 groups (test and control). The test group received LED-PBM with a total energy of 124.2 J/cm2 delivered over 4 sessions (at day0, day+8, day+15 and day+28) lasting 12 minutes each. At day+28, all animals were sacrificed, and their mandibles removed to perform histologic and histomorphometric analysis. Implant osseointegration was evaluated using the computation of bone/implant contact (BIC) index and bone surface/total surface (BS/ TS) ratio. The groups were compared using Student's unpaired t test. Results: BIC index and BS/TS ratio were significantly higher within the test group as compared to the control group (P<0.01). Histologic observations on bone tissues demonstrated that LED-PBM may improve and accelerate dental implant osseointegration: 25% of dental implants analyzed within the test group were completely osseointegrated, versus 12.5% within the control group. Conclusion: This experimental study indicates that LED-PBM contributes to enhancing implant treatment outcomes.

Management of the pediatric OSAS: what about simultaneously expand the maxilla and advance the mandible? A retrospective non-randomized controlled cohort study.

OBJECTIVE/BACKGROUND: This retrospective non-randomized controlled cohort study aimed to evaluate the efficiency of simultaneous maxillary expansion and mandibular advancement for the management of pediatric OSAS. PATIENTS/METHODS: The sample was composed of 94 children treated with an innovative orthopedic device to correct a Class II malocclusion associated with an OSAS. Polysomnographic recordings were performed before and after the treatment. We also included a group of 113 age-matched control patients who had the same pathologies, but who did not receive the orthopedic treatment at the time they undergone polysomnographic exams. Statistical tests evaluated the significance of the evolution of these data, both in treated and untreated control patients. RESULTS: After nine months (±3 months) of treatment, respiratory OSAS symptoms significantly improved: the AHI significantly decreased as it became inferior to the pathological threshold (<1) for 53% of the treated patients' sample, with a greater proportion within the youngest age group (63%). Only two patients still presented a moderate OSAS after treatment, with an AHI slightly superior to 5. This positive evolution of OSAS respiratory symptoms was not observed within the control group, highlighting the real impact of the orthopedic treatment over the children's natural growth. However, sleep remained fragmented following the treatment. CONCLUSIONS: This study confirmed that simultaneous maxillary expansion and mandibular advancement induced a modification of the maxilla-mandibular anatomy, helping in the significant improvement of the respiratory OSAS symptoms. Then, considering these preliminary results, pediatric OSAS can be managed with this new orthopedic strategy, especially if it is performed early.

Concordances and correlations between chronological, dental and bone ages: A retrospective study in French individuals.

Bone and dental maturations are subject to physiological, environmental and pathological variables and are unique to each individual. Numerous methods for age estimation appeared to answer a new demand explained by the contemporary migratory movements and the increase of the crime rates. The objective of this study was to observe the relationships between skeletal and dental maturation stages to estimate which methods can be applied to a French population. This retrospective study was based on panoramic and cephalometric radiographs belonging to 192 (101 females and 91 males) orthodontic patients aged between 9 and 19 years, inhabitants of the Provence-Alpes-Côte d'Azur region. The Demirjian method based on dental calcification was used to estimate dental age. For the assessment of skeletal maturity and bone age, the Cervical Vertebral Maturation (CVM) method (Baccetti et al.) and its computerized version (Decocq et al.) were used. Spearman's correlation tests were performed to estimate the correlation between dental calcification stages and those of cervical vertebral maturation among the study population. The methods of Lin's concordance correlation coefficient and Bland and Altman were used to analyze the concordance between bone, dental and chronological ages. A moderate but statistically significant correlation was obtained between dental and skeletal developmental stages (R = 0.383-0.618). The tooth showing the highest correlation with vertebral stages was the second molar for both sexes. Earlier vertebral maturation stage affiliation was observed in girls. The results confirmed that bone and dental maturations can be assessed to estimate relevant biological ages for children in orthodontic or forensic contexts.

Age estimation from the biometric information of hand bones: Development of new formulas.

INTRODUCTION: In the judicial context of the age estimation of living individuals, a new method was recently proposed, based on the collection of biometric information on hand bones radiographs. The aim of this study was to apply this method to a large French sample to provide new tools for age estimation MATERIALS AND METHODS: The study sample consisted of metacarpals and proximal phalanges measurements of 1003 individuals aged less than 21 years. This sample was divided into two subgroups 1-12 and 13-21 years as the age of 13 is a relevant legal threshold for most European countries. A quadratic discriminant analysis was performed to identify the group to which an individual was most likely to belong. Age estimation formulas were also constructed from linear models: for each subgroup and the total sample. RESULTS: The belonging of an individual to the 1-12 or 13-21 subgroup was determined with a correct classification rate of 89.8%. Age estimation formulas became less precise with age, with a mean absolute error ranging between 11 and 21 months. CONCLUSION: We proposed a two-step procedure for age estimation: firstly, the identification of the age group to which the individual is most likely to belong, and secondly, the age estimation of this individual by applying the appropriate formula.

The Hypoplasic Mandible: What Makes it Different From the Healthy Child?

OBJECTIVE: This study aimed to analyze the morphology of the hypoplasic mandible and its evolution during the growth period to better understand how it differs from the pediatric healthy mandible. METHOD: Three-dimensional mandibular models of hypoplasic and healthy children aged from 39 gestational weeks to 7 years old were analyzed with a morphometric method including data clustering. Morphological distinctions between pathological and healthy mandibles were highlighted. Bilateral and unilateral mandibular hypoplasia were distinguished. RESULTS: The study sample was composed of 31 hypoplasic children and as many sex- and age-matched healthy children. Morphological distinctions between pathological and healthy mandibles were highlighted only from the first year of life. In bilateral hypoplasia, the overall mandibular dimensions were reduced while there was only a ramus asymmetry in unilateral mandibular hypoplasia (mean ± SD of the difference between the Grp03c and Grp03b subgroups: 6.80 ± 6.37 - P value = 1.64e-3 for the height of the left ramus versus 0.18 ± 4.18 - P value = .82 for the height of the right ramus). Supervised classification trees were built to identify the pathology and discriminate unilateral from bilateral mandibular hypoplasia (prediction rates = 81% and 84%, respectively). CONCLUSIONS: Based on a morphometric analysis, we demonstrated that mandibular hypoplasia significantly impacts the mandibular morphology only from the first year of life, with a distinction between bilateral and unilateral hypoplasia.

Morphometric characterization of the very young child mandibular growth pattern: What happen before and after the deciduous dentition development?

OBJECTIVES: Numerous tools have been developed to characterize the morphometry of 3D models. The aim of this study was to apply these techniques to better understand the morphometric growth pattern of healthy children's mandibles. MATERIAL AND METHODS: The study sample was composed of 480 very young children aged from 36 gestational weeks to 7 years old. The sample was divided into three subsamples according to the development stages of their deciduous dentition. Several biometric data were collected on 3D mandibular models. RESULTS: There was homothetic growth during the first years of life. Once all deciduous teeth were fully erupted, the mandibular corpus warped more independently of the ramus, and the inter-individual variability was more pronounced. Throughout the growth period, several subgroups could be identified, highlighting the morphological growth pattern of the mandible. CONCLUSIONS: A particular morphogenesis of the mandible during the growth period was observed, which was correlated with deciduous dentition development. In younger individuals, this morphological pattern was mainly characterized by the progressive closure of the chin symphysis and ramus growth. The tongue movements in the oral space, depending on whether the child was bottle- or breast-fed, may explain this result. As the children grew older, the mandible widened to create sufficient space for the developing teeth buds. During the eruption of deciduous dentition, the mandible took on various morphologies, which was likely based on the child's sex and diet. Therefore, we assume that this mandibular morphogenesis is induced by the functional strains affecting the mandible during deciduous teeth development.

Development of a biometric method to estimate age on hand radiographs.

Age estimation of living individuals aged less than 13, 18 or 21 years, which are some relevant legal ages in most European countries, is currently problematic in the forensic context. Thus, numerous methods are available for legal authorities, although their efficiency can be discussed. For those reasons, we aimed to propose a new method, based on the biometric analysis of hand bones. 451 hand radiographs of French individuals under the age of 21 were retrospectively analyzed. This total sample was divided into three subgroups bounded by the relevant legal ages previously mentioned: 0-13, 13-18 and 18-21 years. On these radiographs, we numerically applied the osteometric board method used in anthropology, by including each metacarpal and proximal phalange of the five hand rays in the smallest rectangle possible. In that we can access their length and width information thanks to a measurement protocol developed precisely for our treatment with the ORS Visual® software. Then, a statistical analysis was performed from these biometric data: a Linear Discriminant Analysis (LDA) evaluated the probability for an individual to belong to one of the age group (0-13, 13-18 or 18-21); and several multivariate regression models were tested for the establishment of age estimation formulas for each of these age groups. The mean Correlation Coefficient between chronological age and both lengths and widths of hand bones is equal to 0.90 for the total sample. Repeatability and reproducibility were assessed. The LDA could more easily predict the belonging to the 0-13 age group. Age can be estimated with a mean standard error which never exceeds 1 year for the 95% confidence interval. Finally, compared to the literature, we can conclude that estimating an age from the biometric information of metacarpals and proximal phalanges is promising.