Clinical Indications to Germectomy in Pediatric Dentistry: A Systematic Review

Germectomy is a procedure often required in patients at developmental age. It is defined as the surgical removal of the third molar at a very specific stage of development. The aim of this study was to systematically analyze the literature in terms of clinical indications for germectomy in patients at developmental age. Literature searches were performed using PubMed, Google Scholar, Cochrane Library and Scopus from 1952 to 30 June 2021. The study protocol was registered after the screening stage (PROSPERO CRD42021262949). The search strategy identified 3829 articles: 167 from PubMed, 2860 from Google Scholar, 799 from Cochrane Library and 3 from Scopus. Finally, eight full-text papers were included into the qualitative analysis. Based on the included studies, clinical indications for germectomy were mainly related to orthodontic causes, infectious and cariogenic causes and prophylaxis. Based on these results, it is not possible to present evidence-based clinical indications for germectomy in patients at developmental age. Clinical trials on this subject focused specifically on patients at developmental age are awaited.

Managing Curvatures in an Atypical Mandibular Third Molar: “Radix Paramolaris”

Third molars are known for morphological variations and atypical anatomy. Although these teeth pose difficulty in root canal treatment due to limited accessibility however, retaining third molars has gained importance in the present scenario due to their crucial role in serving as an abutment or in auto transplantation cases. This case report presents a case of Radix Paramolaris in mandibular third molar with severe curvatures of root canals in different planes and discusses its management with controlled memory files and tactile-controlled activation technique. Keywords: Radix Paramolaris, Curved canals, Controlled memory files, Tactile-controlled activation technique.

Evaluating the Relationship between Mandibular Third Molar and Mandibular Canal with Semiautomatic Segmentation: A Pilot Study on CBCT Datasets

Inferior alveolar nerve injury is the main complication in mandibular third molar surgery. In this context, cone-beam computed tomography (CBCT) has become of crucial importance in evaluating the relationship between mandibular third molar and inferior alveolar nerve. Due to the growing interest in preoperative planning in oral surgery, several post-processing techniques have been implemented to obtain three-dimensional reconstructions of a volume of interest. In the present study, segmentation techniques were retrospectively applied to CBCT images in order to evaluate whether post-processing could offer better visualization of the structures of interest. Forty CBCT examinations performed for inferior third molar impaction were analyzed. Segmentation and volumetric reconstructions were performed. A dataset composed of multiplanar reconstructions for each study case, including segmented images, was submitted for evaluation to two oral surgeons, two general practitioners and four residents in oral surgery. The visualization of root morphology, canal course, and the relationship with mandibular cortical bone on both native CBCT and segmented images were assessed. Inter-rater agreement showed values of intraclass correlation coefficient (ICC) above 0.8 for all the examined parameters. Oral surgeons presented higher ICC values (p < 0.05). Segmented images can improve preoperative evaluation of the third molar and its relationship with the surrounding anatomical structures compared to native CBCT images. Further evaluation is needed to validate these preliminary results.

Single-Cell Transcriptomic Profiling of Human Dental Pulp in Sound and Carious Teeth: A Pilot Study

A comprehensive understanding of dental pulp cellular compositions and their molecular responses to infection are crucial for the advancement of regenerative dentistry. Here, we presented a pilot study of single-cell transcriptomic profiles of 6,810 pulpal cells isolated from a sound human maxillary third molar and three carious teeth with enamel and deep dental caries. We observed altered immune cell compositions of the dental pulp in deep, but not enamel ones. Differential expression analysis revealed up-regulation of several pro-inflammatory, anti-inflammatory, and mineralization-related genes in the immune and stromal cells of the deep dental caries. Making use of an algorithm for predicting cell-to-cell interactions from single-cell transcriptomic profiles, we showed an increase in cell-cell interactions between B cells, plasma cells and macrophages, and other cell types in deep dental caries, including those between TIMP1 (odontoblasts)—CD63 (myeloid cells), and CCL2 (macrophages)—ACKR1 (endothelial cells). Collectively, our work highlighted the single-cell level gene regulations and intercellular interactions in the dental pulps in health and disease.

Maxillary Distomolar Associated with Dentigerous Cyst: An Unusual Entity

Supernumerary teeth may be encountered as an incidental finding on a radiograph. When impacted, they may be associated with clinical signs related to different problems such as failure of eruption, teeth displacement, root resorption or cystic lesions. They may occur in primary and permanent dentition, in both the maxilla and mandible and can be single or multiple in patients with syndromes. Mesiodens is the most commonly impacted tooth and appears between the central maxillary incisors in pediatric ages. Supernumerary teeth distal to the third molar are rare, usually impacted and referred to as a distomolar. A 46-year-old male consulted with the main complaint of pain on the left side of the maxilla. A panoramic radiograph revealed a right impacted maxillary fourth molar located posterior to the third molar associated with a pericoronal radiolucency. The supernumerary tooth was removed surgically under local anesthesia and the pericoronal lesion enucleated. Histopathological examination was consistent with the diagnosis of a dentigerous cyst associated with an impacted distomolar. Healing was uneventful, and the patients remained asymptomatic. The occurrence of a maxillary distomolar is rare and even rarer the association with a dentigerous cyst.

Automated Prediction of Extraction Difficulty and Inferior Alveolar Nerve Injury for Mandibular Third Molar Using a Deep Neural Network

Extraction of mandibular third molars is a common procedure in oral and maxillofacial surgery. There are studies that simultaneously predict the extraction difficulty of mandibular third molar and the complications that may occur. Thus, we propose a method of automatically detecting mandibular third molars in the panoramic radiographic images and predicting the extraction difficulty and likelihood of inferior alveolar nerve (IAN) injury. Our dataset consists of 4903 panoramic radiographic images acquired from various dental hospitals. Seven dentists annotated detection and classification labels. The detection model determines the mandibular third molar in the panoramic radiographic image. The region of interest (ROI) includes the detected mandibular third molar, adjacent teeth, and IAN, which is cropped in the panoramic radiographic image. The classification models use ROI as input to predict the extraction difficulty and likelihood of IAN injury. The achieved detection performance was 99.0% mAP over the intersection of union (IOU) 0.5. In addition, we achieved an 83.5% accuracy for the prediction of extraction difficulty and an 81.1% accuracy for the prediction of the likelihood of IAN injury. We demonstrated that a deep learning method can support the diagnosis for extracting the mandibular third molar.

Effects of Selective Alveolar Decortication on the Periodontal Complex

Background Modification of bone turnover has been reported following selective alveolar decortication but the molecular signals in the periodontal ligament space (PDL) remain unanswered. The objective of this study was to understand how selective alveolar decortication affects the biological reactions in the periodontal ligament. Methods Selective alveolar decortication in wild-type mice (n=25) was performed on mandibular right buccal cortical plate adjacent to the mandibular right third molar and euthanized at 3, 7, 14 and 28 days. We also performed selective alveolar decortication in Lrp5ACT (n=5) mice and Ad-Dkk1 treated mice (n=5), and euthanized at 7 days. The periodontium around the mandibular third molars were examined using histology, immunohistochemical analyses for osteogenic markers, TGF-β, RANKL, TRAP and alkaline phosphatase activity. Results The expression of osteogenic markers in the wild-type PDL was maintained during healing time period after selective alveolar decortication. Increased osteoclast activity in the wild-type mice was observed at 3 and 7 days after selective alveolar decortication. The PDL in Lrp5G171V (Lrp5ACT) mice and adenovirus Dkk1 (Ad-Dkk1) treated mice also showed insignificant changes in the expression of osteogenic markers following selective alveolar decortication. In Lrp5ACT mice where there was a reduction of bone resorption, selective alveolar decortication caused a dramatic increase in osteoclast activity. Conclusions Selective alveolar decortication affects only bone turnover, but not the expression of osteogenic markers in the PDL.