Third molar agenesis as a potential marker for craniofacial deformities

Root Curvature in Non-Syndromic Oral Clefts: A Case-Control Study in a Brazilian Population

OBJECTIVE

This study assesses the degree of root curvature in patients with non-syndromic cleft lip and/or palate (NSCL/P).

DESIGN

Retrospective. Case-control study.

SETTING

Root curvature was assessed in lower premolars and molars in 800 panoramic radiographs: 400 from patients with cleft and 400 from healthy control individuals. Root curvature was classified according to its angulation, as well as its apical, medial, or coronal localization.

RESULTS

The frequency of mild curvature in the NSCL/P group compared to the control group was higher in premolars especially in the left second premolar in cleft palate (OR: 6.91; 95% CI: 3.23-14.77; P < .0001). The frequency of moderate curvature in molars was significantly higher in the cleft group, with the highest risk in the right first molar in the cleft lip group (OR: 2.74; 95% CI: 1.67-4.52; P < .0001). Inclination was more frequently observed in the apical third of the root in the group with cleft, whereas for the control group, the curvature was more frequent in the medial third. In patients with cleft, the OR of curvature in the apical third was significant in premolars (left lower second premolar: Cleft lip, OR: 1.91; 95% CI: 1.04-3.52; P = .03; right lower second premolar: Cleft lip, OR: 1.91, 95% CI: 1.04-3.50; P = .03, cleft lip and palate, OR: 1.75; 95% CI: 1.12-2.73; P = .01).

CONCLUSION

The results of the current study indicate differences in root curvature in patients with non-syndromic cleft lip and/or palate, which should be considered during the dental treatment planning of patients.

A rare find of a maxillary third molar with five roots: a case report of an unusual morphology

Third molars are frequently absent or impacted; their unpredictable prevalence and morphology, with frequent anatomical variations, is a challenge for the practitioner. The number of roots of the upper third molars vary from one to five, but five roots upper third molars' cases are extremely rare. The case reported here is of a normotrophic male patient, with no significant general medical history, having extracted an impacted maxillary upper molar, with an unusual position and dimensions and five completely separated formed roots, orientated in diverse directions. It highlights the importance of using the correct surgical technique, without excessive pressure, for avoiding the fracture of the maxillary tuberosity, the displacement of the molar into the pterygopalatine fossa or the opening of the maxillary sinus, especially in the absence of good quality imagistic information like cone-beam computed tomography. The case presented in this paper is very rare and highlights the significance of anatomical knowledge, which is mandatory for managing these cases, to avoid trauma, accidents, and complications and to maintain an optimal time of extraction, since such variations occur, and the conventional radiographs do not offer enough data to clarify the diagnosis.

Number of Teeth Is Related to Craniofacial Morphology in Humans

Simple Summary

In modern humans, congenital absence of one or more permanent teeth has a prevalence of 22.6% when considering the third molars and of 6.4% when not. Its high prevalence, in conjunction with evolutionary findings pinpointing to a steady reduction in teeth number, raises the question whether the congenital absence of teeth in modern humans is an evolutionary trend rather than an anomaly. Previous studies have shown that modern humans with less teeth also have smaller faces; however, the association between teeth number and craniofacial morphology remains unclear. Here, we show that less teeth are associated with a flatter profile and a decreased facial height. These findings support the claim of a broader relationship between number of teeth and overall craniofacial development and have evolutionary implications, since face reduction comprises also an evolutionary trend in humans.

Abstract

One of the most common dental anomalies in humans is the congenital absence of teeth, referred to as tooth agenesis. The association of tooth agenesis to craniofacial morphology has been previously investigated but remains unclear. We investigated this association by applying geometric morphometric methods in a large sample of modern humans. In line with previous studies, we report here that a reduced teeth number is linked to a less convex profile, as well as to a shorter face. The effects were similar for males and females; they increased as the severity of the tooth agenesis increased and remained unaltered by the inclusion of third molars and of allometry in the analysis. Furthermore, in cases with tooth agenesis only in the maxilla, there was no detectable effect in mandibular shape, whereas maxillary shape was affected independently of the location of missing teeth. The robustness of the present sample along with the shape analysis and the statistical approach applied, allowed for thorough testing of various contributing factors regarding the presence but also the magnitude of effects. The present findings suggest a relationship between number of teeth and overall craniofacial development and have evolutionary implications.

Pulp enlargement in individuals born with cleft lip and palate pulp, a radiographic study from the cleft lip and palate service of paraiba, Brazil'

PURPOSE

Pulp chamber enlargement impacts endodontic treatment planning. The aim of this study was to evaluate alterations in pulp chamber size of posterior teeth in individuals born with cleft lip with or without cleft palate.

METHODS

Ninety individuals were treated at the Cleft Lip and Palate Service of the University Hospital Lauro Wanderley, Federal University of Paraíba, between the ages of 4 and 15 years born with cleft lip with or without cleft palate were selected. Ninety-nine patients from the archives of the residency program in Orthodontics of the Brazilian Dental Association (ABO) were paired by sex and age as a comparison group. Radiographs were evaluated by a single examiner, observing the presence/absence of an enlarged pulp chamber in the first and second permanent molars of all quadrants. Chi square or Fisher's exact tests were used (α = 0.05) in all comparisons.

RESULTS

Pulp enlargement was more frequently found among individuals born with cleft lip with or without cleft palate (p = 0.0005). However, pulp enlargement frequency was different among subjects born with clefts (p = 0.0006). Pulp enlargement was more common in the maxilla, in both groups. Individuals born with cleft lip with or without cleft palate more often had six or more teeth affected (p = 0.02). Furthermore, individuals with a bilateral cleft more often had six or more teeth affected in comparison to unilateral cases (p = 0.002).

CONCLUSION

Pulp enlargement is a frequent finding, particularly among individuals born with cleft lip with or without cleft palate, with a higher prevalence in the maxilla.

Tooth agenesis-related GLI2 and GLI3 genes may contribute to craniofacial skeletal morphology in humans

OBJECTIVE

The present cross-sectional, multi-centre, genetic study aimed to determine, whether single nucleotide polymorphisms (SNPs) in tooth agenesis (TA)-associated GLI2 and GLI3 genes contribute to the development of craniofacial skeletal morphology in humans.

DESIGN

Orthodontic patients from an ethnically heterogeneous population were selected for the present study (n = 594). The presence or absence of TA was determined by analysis of panoramic radiography and dental records. The subjects were classified according to their skeletal malocclusion and facial growth pattern by means of digital cephalometric analysis. Genomic DNA was extracted from squamous epithelial cells of the buccal mucosa and SNPs in GLI2 (rs3738880, rs2278741) and GLI3 (rs929387, rs846266) were analysed by polymerase chain reaction using TaqMan chemistry and end-point analysis.

RESULTS

Class II skeletal malocclusion presented a significantly lower frequency of TA (P < 0.05). Subjects without TA showed significantly higher ANB angles (P < 0.05). Genotype and/or allele distributions of the SNPs in GLI2 (rs3738880, rs2278741) and GLI3 (rs846266) were associated with the presence of TA (P < 0.05). The SNPs rs3738880, rs2278741 and rs929387 were also associated with some type of skeletal malocclusion (P < 0.05), but not with the facial growth pattern (P > 0.05). The G allele for TA-related GLI2 rs3738880 was strongly linked to the presence of Class III skeletal malocclusion (OR = 2.03; 95% CI = 1.37-3.03; P<3125 × 10^-6). GLI2 rs2278741 C allele was overrepresented in individuals without TA, suggesting it as a protective factor for this dental phenotype (OR = 0.43; 95% CI = 0.24-0.78; P<625 × 10^-5).

CONCLUSION

The present study suggests that SNPs in TA-associated GLI2 and GLI3 genes may also play a role in the development of skeletal malocclusions. rs3738880 and rs2278741 in GLI2 seems to contribute to the genetic background for skeletal Class III and TA, respectively. TA could be an additional predictor of craniofacial morphology in some cases. Further research replicating the reported associations should be performed.

The Relationship between Agenesis of Third Molar and Craniofacial Morphology in Orthodontic Patients

Aims and Objectives:

The aim of this study was to evaluate the association between third molar agenesis and craniofacial morphology in a group of Iranian orthodontic patients.

Materials and Methods:

A total of 164 high-quality lateral cephalograms and panoramic radiographs were included in the study. Eighty-two radiographs with the absence of at least one-third molar were assigned to agenesis group and other 82 radiographic records were served as control group. Cephalometric analysis was performed, and the results were compared between the two groups using Independent Samples Student's t-test.

Results:

Significant differences were found in SNA, ANB, sum of posterior angles, and lower gonial angle between the study groups. All of them were smaller in the agenesis group.

Conclusion:

Third molar agenesis in this group of Iranian subjects is associated with deficient maxillary development and brachyfacial and hypodivergent skeletal pattern.