Presence and Maturation Dynamics of Mandibular Third Molars and Their Influence on Late Mandibular Incisor Crowding: A Longitudinal Study

The objective of this study was to investigate the relationship between the absence, presence and dynamics of mandibular third molar development and the occurrence and amount of late mandibular incisor crowding. Dental plaster casts and panoramic radiographs of 72 orthodontically untreated subjects from the Nittedal growth study, Norway were analyzed. The subjects were recalled for a checkup at 12, 15, 18 and 21 years of age. Mandibular incisor crowding was assessed using Little’s irregularity index and dental maturation of the third molars by the Cameriere’s index. The majority of the subjects (64%) had ≥1 mm increase in irregularity; 22% experienced an increase of 0.1–0.9 mm and 14% had unchanged or decreased irregularity. Incisor irregularity increased with age, regardless of absence or presence of third molars. The amount of change in incisor irregularity from 12 to 21 years did not differ significantly between subjects with hypodontia of third molars, extraction and those with third molars present. No differences were observed between erupted, unerupted or impacted third molars. No correlation was found between the amount of change in irregularity and maturation of the third molars. In conclusion, occurrence and amount of mandibular late incisor crowding is not significantly influenced by the presence of mandibular third molars or their development dynamics.

Clinical Implications of Growth Hormone Deficiency for Oral Health in Children: A Systematic Review

Growth hormone (GH) is involved in the regulation of the postnatal dental and skeletal growth, but its effects on oral health have not been clearly defined. This paper aims to provide a review of current clinical knowledge of dental caries, tooth wear, developmental enamel defects, craniofacial growth and morphology, dental maturation, and tooth eruption in growth hormone deficient (GHD) children. A systematic review was carried out using Scopus, MEDLINE-EbscoHost and Web of Science from 2000 to May 2021. PRISMA guidelines for reporting systematic reviews were followed. All the selected studies involved groups under eighteen years of age, covering a total of 465 GHD patients. The studies that were selected provide reliable evidence for delayed dental maturity and orthodontic disturbances in GHD patients. Data on dental hard tissues pathology are scarce and are limited to occurrences of dental caries. GHD children showed abnormal craniofacial morphology with reduced mandibular dimensions, with a resulting tendency towards Angle’s Class II occlusion, which affected up to 31% of patients. Dental age has been shown to be delayed in GHD patients by about 1 to 2 years. Moreover, the risk of dental caries in children with GHD decreases with increasing levels of vitamin D. Hence, further studies would be valuable for evaluating the risk of various oral health problems and to organize targeted dental care for this vulnerable group.

The Correlation between Dental Stages and Skeletal Maturity Stages

Introduction. The determination of skeletal maturity stages is very important in orthodontic treatment planning, especially skeletal discrepancies in growing individuals. A hand-wrist radiograph is considered the most accurate approach for skeletal maturity detection. Dental calcification stages have been suggested as an alternative diagnostic method to decrease radiation exposure. The recent study is aimed at detecting the efficacy of dental calcification stages in assessing skeletal maturity during the prepubertal and pubertal growth periods. Methods. Patients’ records were collected from the Aleppo Orthodontic Center. Dental maturity stages were assessed from a panoramic radiograph using the Demirjian method, while skeletal maturity stages were determined using the Björk method. Four permanent left mandibular teeth were included (canine, 1st premolar, 2nd premolar, and 2nd molar) for the study. Results. From 517 records, 295 records (145 males and 150 females) were included. The Spearman rank-order correlation coefficients between skeletal maturation and dental maturation were strong and statistically significant (ranging from 0.789 to 0.835). The highest correlation was between skeletal stages and the second molar ( r = 0.829 and 0.88 in males and females, respectively). Receiver operating characteristic (ROC ) curve suggested a high validity of the sum of dental stages for the four teeth in identifying MP3= stage (sensitivity was 70%, specificity was 92.77%, and ROC area was 0.81) but not for MP3cap (sensitivity was 50.85%, specificity was 81.36%, and ROC area was 0.66). Conclusions. The correlation between the skeletal maturity stages and the dental calcification stages was high. The orthodontist can use the dental stages as a definite diagnostic tool for prepubertal growth period.

Presence and Maturation Dynamics of Mandibular Third Molars and Their Influence on Late Mandibular Incisor Crowding: Longitudinal Study

OBJECTIVE: To investigate the relationship between the presence and dynamics of mandibular third molar development and the occurrence and amount of late mandibular incisor crowding. MATERIALS AND METHODS: Dental plaster casts and panoramic radiographs of 72 orthodontically untreated subjects from the Nittedal growth study, Norway were analysed. The subjects were recalled for check-up at 12, 15, 18 and 21 years of age. Mandibular incisor crowding was assessed using the Little’s irregularity index and dental maturation of the third molars by the Cameriere’s index.RESULTS: The majority of the subjects (64%) had ≥1mm increase in irregularity; 22% experienced increase of 0.1-0.9mm and 14% had unchanged or decreased irregularity. Incisor irregularity increased with age, regardless of absence or presence of third molars. The amount of change in incisor irregularity from 12 to 21 years did not differ significantly between subjects with hypodontia of third molars, extraction and those with third molars present. No differences were observed between erupted, unerupted or impacted third molars. No correlation was found between the amount of change in irregularity and maturation of the third molars.CONCLUSIONS: Occurrence and amount of mandibular late incisor crowding is not significantly influenced by presence or development dynamics of mandibular third molars.

Dental Subphenotypes in Infants With Orofacial Clefts—A Longitudinal Population-Based Retrospective Radiographic Study of the Primary and Secondary Dentitions

Objectives: To determine the developmental patterns of primary and secondary dentitions in infants with orofacial clefts. Design: Retrospective, longitudinal, population-based cohort study. Materials: Longitudinal records and radiographs of 192 nonsyndromic Northern European infants with isolated unilateral cleft lip (UCL, n = 111) and isolated cleft palate (CP, n = 81). Methods: Radiographic assessments of primary and secondary dentition anomalies and dental maturation, by gender and cleft severity for comparisons between the groups and with historical controls. Results: In infants with UCL, the frequencies of dental anomalies were high in both primary (38.7%) and secondary (18.0%) dentitions. Primary and secondary dentition anomalies were not observed in infants with CP and different in the UCL group ( P = .003). Risk differences involved primary supernumerary teeth ( P = .0001) and talon cusp formation ( P = .0001), and secondary tooth agenesis ( P = .001) of the maxillary lateral incisor on the side of the cleft lip. Delayed primary and secondary dental maturation occurred in the UCL and CP groups, greater in infants with UCL ( P < .0001). Primary and secondary dental maturation featured sexual dimorphism with greater delay in males (UCL, P < .0001; CP, .0001 > P = .001). The effect of cleft severity on dental maturation was significant in infants with UCL ( P = .0361) and CP ( P = .0175) in the primary but not in the secondary dentition. Conclusions: There were different dental anomalies in the primary and secondary dentitions in operated infants with UCL and no dental anomalies in unoperated infants with CP. Dental maturation was delayed in infants with UCL and CP with greater delay in males compared to females.

Body mass index in relation to dental maturation of 10 to 14 years old school children in Erbil city. A cross-sectional prospective study.

Background and Objectives: Estimation of dental age is based upon the rate of development and calcification of tooth buds and their progressive sequence of eruption in the oral cavity. The tooth calcification provides a valuable indicator of dental age and serves as an index of the maturation of the child. The aim of this study is to determine whether Body Mass Index (BMI) has association with dental maturation. Materials and Methods: A cross sectional study design was applied for the present study, 383 school children were participated in this study which nominated from Erbil city. For the sample to be representative the city was divided in to six geographic areas according to the municipalities, the samples randomly selected school children of 10 to 14 years old from both genders. The height and the weight of each participant had been recorded in the college of dentistry / Hawler Medical University in order to calculate the body mass index of the following the guidelines of centers of disease control (CDC) , at the same time an orthopantomography radiograph had been used to investigate the stage of the dental maturation using the Demirjian method, finally, the relationship between BMI and dental maturation were investigated using chi square test with P value of ≤ 0.05 was considered significant difference. Result: there was a statistically significant relationship between dental maturation and BMI. The majority (93.6%) of samples with under-mature dentition were under-weight at the same time. The vast majority (96%) of samples with mature dentition had normal BMI. In the same manner, majority (91.7%) of samples with over mature dentition were over-weight too. Chi square test was used to find out the association and P-value was 0.001 Conclusion: In conclusion, normal weight students have normal dental maturation, underweight students have under dental maturation and overweight or obese students have over dental maturation. Keywords: body mass index, Demirjian, Orthopantomography.

Growth and development of the third permanent molar in Paranthropus robustus from Swartkrans, South Africa

Third permanent molars (M3s) are the last tooth to form but have not been used to estimate age at dental maturation in early fossil hominins because direct histological evidence for the timing of their growth has been lacking. We investigated an isolated maxillary M3 (SK 835) from the 1.5 to 1.8-million-year-old (Mya) site of Swartkrans, South Africa, attributed to Paranthropus robustus. Tissue proportions of this specimen were assessed using 3D X-ray micro-tomography. Thin ground sections were used to image daily growth increments in enamel and dentine. Transmitted light microscopy and synchrotron X-ray fluorescence imaging revealed fluctuations in Ca concentration that coincide with daily growth increments. We used regional daily secretion rates and Sr marker-lines to reconstruct tooth growth along the enamel/dentine and then cementum/dentine boundaries. Cumulative growth curves for increasing enamel thickness and tooth height and age-of-attainment estimates for fractional stages of tooth formation differed from those in modern humans. These now provide additional means for assessing late maturation in early hominins. M3 formation took ≥ 7 years in SK 835 and completion of the roots would have occurred between 11 and 14 years of age. Estimated age at dental maturation in this fossil hominin compares well with what is known for living great apes.