Autotransplanted premolars with incomplete root formation in a growing patient with multiple missing teeth

Factors influencing root resorption in retained mandibular second deciduous molars with congenital absence of second premolars: a cross-sectional study

BACKGROUND

There are currently no studies that quantitatively compare the relationship of root resorption to the patient's systemic history or craniofacial and intraoral morphology, especially in relation to possible host factors. Thus, this study aimed to clarify the factors associated with root resorption in retained mandibular second deciduous molars with the congenital absence of second premolars and predict the prognosis of retained mandibular second deciduous molars.

METHODS

A cohort of 5547 patients who visited the orthodontic clinic at Tokyo Medical and Dental University Dental Hospital between 2013 and 2022 was screened. Lateral cephalometric radiographs, panoramic radiographs, upper and lower dental models, and orthodontic treatment questionnaires were used as reference materials to apply the inclusion and exclusion criteria. Ultimately, 111 patients were included in the analyses. The patients were divided into two groups based on the root resorption levels of the retained mandibular second deciduous molars. Those with less root resorption were classified under the good condition (GC) group, whereas those with more root resorption were classified under the poor condition (PC) group. Demographic, clinical, and cephalometric parameters were compared between the groups. A multivariate logistic regression model was used to predict the probability of root resorption.

RESULTS

The prevalence of congenitally missing mandibular second premolars with persistent mandibular second deciduous molars was 2.0%. In a total of 111 patients, eighty-three teeth (53.2%) were classified into the GC group, whereas 73 teeth (46.8%) were classified into the PC group. The Frankfort-mandibular plane angle (FMA) [odds ratio (OR): 0.87], Frankfort-mandibular incisor angle (FMIA) (OR: 0.93), overbite (OR: 1.38), adjacent interdental space (OR: 1.46), distance from occlusal plane (OR: 0.80), and caries treatment (OR: 7.05) were significantly associated with the root resorption of the retained mandibular second deciduous molars.

CONCLUSIONS

Our findings suggest that skeletal morphology, oral morphological patterns, and history contribute to root resorption in retained mandibular second deciduous teeth with congenital absence of subsequent permanent teeth.

What is the survival rate of deciduous molars in cases with agenesis of premolar successors? A systematic review

OBJECTIVES

To systematically review the literature on the survival rate of deciduous molars in cases of agenesis of premolar successors.

MATERIALS AND METHODS

Four electronic databases and partial grey literature were searched up to November 2020. The PECOS eligibility criteria included (P) second deciduous molar (E) exposed to agenesis of a premolar successor (O) evaluated by the survival rate in the oral cavity, infraocclusion, and root resorption through (S) observational studies. Risk of bias (RoB) was assessed using the checklists from the Joanna Briggs Institute and the level of evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) tool.

RESULTS

Three studies were included: one with low, one with moderate, and one with high RoB. Synthesis methods included the frequency of persistent deciduous second molars during the follow-up. Approximately 82% to 89% remained in the oral cavity after 5 to 13 years. The incidence of root resorption was 11%, and the infraocclusion was 1 mm. The level of evidence was considered low for each outcome. There was considerable RoB regarding the observational studies and a need for clinical and radiographic monitoring of the deciduous molars.

CONCLUSIONS

Maintaining a deciduous molar in the oral cavity in patients with agenesis of the premolar successor is a viable clinical choice since 82% to 89% of the retained molars evaluated were in good condition over a follow-up ranging from 5 to 13 years. Infraocclusion and root resorption did not seem to increase considerably. The level of evidence was considered low for each outcome.