Unequal Impact of COL1A1 and COL1A2 Variants on Dentinogenesis Imperfecta.

Dentinogenesis imperfecta (DI) is the main orodental manifestation of osteogenesis imperfecta (OI) caused by COL1A1 or COL1A2 heterozygous pathogenic variants. Its prevalence varies according to the studied population. Here, we report the molecular analysis of 81 patients with OI followed at reference centers in Brazil and France presenting COL1A1 or COL1A2 variants. Patients were submitted to clinical and radiographic dental examinations to diagnose the presence of DI. In addition, a systematic literature search and a descriptive statistical analysis were performed to investigate OI/DI phenotype-genotype correlation in a worldwide sample. In our cohort, 50 patients had COL1A1 pathogenic variants, and 31 patients had COL1A2 variants. A total of 25 novel variants were identified. Overall, data from a total of 906 individuals with OI were assessed. Results show that DI was more frequent in severe and moderate OI cases. DI prevalence was also more often associated with COL1A2 (67.6%) than with COL1A1 variants (45.4%) because COL1A2 variants mainly lead to qualitative defects that predispose to DI more than quantitative defects. For the first time, 4 DI hotspots were identified. In addition, we showed that 1) glycine substitution by branched and charged amino acids in the α2(I) chain and 2) substitutions occurring in major ligand binding regions-MLRB2 in α1(I) and MLBR 3 in α2(I)-could significantly predict DI (P < 0.05). The accumulated variant data analysis in this study provides a further basis for increasing our comprehension to better predict the occurrence and severity of DI and appropriate OI patient management.

Partial caries removal in deep caries lesions: a 5-year multicenter randomized controlled trial.

OBJECTIVE: This multicenter randomized controlled clinical trial aimed to compare the outcomes of stepwise excavation (SW) and partial caries removal (PCR) regarding the maintenance of pulp vitality in deep caries lesions over 5 years. METHODS: At baseline, 299 permanent molars with deep caries lesions were randomly assigned to control or test groups. The control group received the stepwise excavation treatment (SW), while the test group received partial caries removal from the pulpal wall followed by restoration in a single session (PCR). Treatments were conducted in two centers located in the cities of Porto Alegre (South Brazil) and Brasília (Midwest Brazil). Survival analysis was performed to compare PCR and SW over time (Weibull regression models). The primary outcome of this study was pulp vitality, determined by the combination of the following characteristics: positive response to cold test, negative response to percussion, absence of spontaneous pain, and absence of periapical lesion (radiographic examination). RESULTS: This 5-year study includes data pertaining to 229 teeth: 121 teeth actually examined at the 5-year appointment, and 108 teeth contributed with data collected in previous follow-ups (18 months or 3 years). Survival analysis showed success rates of 80% in PCR group and 56% in SW group (p < 0.001). Failure was significantly associated with treatment [PCR, HR=0.38; 95%CI=0.23-0.63)] and region [South, HR=2.22; 95%CI=1.21-4.08]. CONCLUSION: PCR significantly reduced the occurrence of pulp necrosis when compared with SW. CLINICAL RELEVANCE: This study supports the PCR as a single-visit technique to manage deep caries lesions in permanent teeth.

Partial removal of carious dentine: a multicenter randomized controlled trial and 18-month follow-up results.

AIM: The aim of this study was to evaluate the effectiveness of partial removal of carious dentine and restoration in a single session (PDR) and stepwise excavation (SW), both of which are treatments for deep carious lesions, in Public Health Services in Brazil. INCLUSION CRITERIA: patients ≥6 years old, permanent molars with deep caries lesions (having a radiolucency halfway or more into dentine) and pulp vitality but absence of spontaneous pain, positive percussion test, and periapical alterations. The subjects received either PDR (test group) or SW (control group). The radiological and clinical exams were performed after a mean time of 18 months. OUTCOMES: success was defined as pulp sensitivity to cold test and absence of periapical alterations. RESULTS: Of the 299 treatments performed, 146 were SW and 153 were PDR; 122 were amalgam restorations and 168 resin-composite restorations. There were no differences between the groups regarding the baseline characteristics (i.e. age, gender and family income). After 18 months, 212 evaluations were performed, which indicated 99 and 86% success rates in the PDR and SW groups, respectively (p = 0.016). Reasons for failure were: PDR - 1 pulpitis; SW - 8 pulpitis; 1 osteitis; 4 necrosis; 1 endodontic treatment. None of the baseline variables were significantly associated with the outcomes. CONCLUSION: The retention of carious dentine does not interfere in pulp vitality. Data from this 18-month study suggest that the procedure of reopening the cavity to remove the residual infected dentine is not necessary.

Randomized trial of partial vs. stepwise caries removal: 3-year follow-up.

This randomized, multicenter clinical trial evaluated the effectiveness of 2 treatments for deep caries lesions - partial caries removal (PCR) and stepwise excavation (SW) - with respect to the primary outcome of pulp vitality for a 3-year follow-up period. Inclusion criteria were as follows: patients with permanent molars presenting deep caries lesions (lesion affecting ≥ 1/2 of the dentin on radiographic examination), positive response to a cold test, absence of spontaneous pain, negative sensitivity to percussion, and absence of periapical lesions (radiographic examination). Teeth randomly assigned to PCR (test) received incomplete caries removal and filling in a single session. Outcome success was evaluated by assessment of pulp vitality, determined by pulp sensitivity to a cold test and the absence of periapical lesions. Data were analyzed by a Weibull regression model with shared frailty term (survival analysis). At baseline, 299 treatments were executed: PCR, 152 and SW, 147. By the end of the 3-year follow-up period, 213 teeth had been evaluated. Adjusted survival rates were 91% for PCR and 69% for SW (p = 0.004). These results suggest that there is no need to re-open a cavity and perform a second excavation for pulp vitality to be preserved (Clinical trials registration NCT00887952).

Autosomal-dominant ankyloglossia and tooth number anomalies.

Ankyloglossia is a congenital oral anomaly characterized by the presence of a hypertrophic lingual frenulum. It frequently accompanies X-linked cleft palate and is sometimes seen alone due to mutations in the gene encoding the transcription factor TBX22, while knockout of Lgr5 in the mouse results in ankyloglossia. The aim of the present study was to characterize the phenotype and to verify sequence variations in the LGR5 gene in a Brazilian family with ankyloglossia associated with tooth number anomalies. Twelve individuals of three generations were submitted to physical, oral, and radiographic examinations and molecular analysis. Eight had ankyloglossia with various degrees of severity. Six also had hypodontia in the lower incisor region; one had a supernumerary tooth in this region, and another had a supernumerary tooth in the lower premolar region. The characterization of this family determined an autosomal-dominant inheritance and excluded the LGR5 gene mutations as being involved in the pathogenesis of this condition.