Malposition of Unerupted Mandibular Second Premolar in Children with Cleft Lip and Palate

Objective: To test the null hypothesis that there is no relationship between infraocclusion and the occurrence of other dental anomalies in subjects selected for clear-cut infraocclusion of one or more deciduous molars. Materials and Methods: The experimental sample consisted of 99 orthodontic patients (43 from Boston, Mass, United States; 56 from Jerusalem, Israel) with at least one deciduous molar in infraocclusion greater than 1 mm vertical discrepancy, measured from the mesial marginal ridge of the first permanent molar. Panoramic radiographs and dental casts were used to determine the presence of other dental anomalies, including agenesis of permanent teeth, microdontia of maxillary lateral incisors, palatally displaced canines (PDC), and distal angulation of the mandibular second premolars (MnP2-DA). Comparative prevalence reference values were utilized and statistical testing was performed using the chi-square test (P , .05) and odds ratio. Results: The studied dental anomalies showed two to seven times greater prevalence in the infraocclusion samples, compared with reported prevalence in reference samples. In most cases, the infraoccluded deciduous molar exfoliated eventually and the underlying premolar erupted spontaneously. In some severe phenotypes (10%), the infraoccluded deciduous molar was extracted and space was regained to allow uncomplicated eruption of the associated premolar. Conclusion: Statistically significant associations were observed between the presence of infraocclusion and the occurrence of tooth agenesis, microdontia of maxillary lateral incisors, PDC, and MnP2-DA. These associations support a hypothesis favoring shared causal genetic factors. Clinically, infraocclusion may be considered an early marker for the development of later appearing dental anomalies, such as tooth agenesis and PDC. (Angle Orthod. 2010;80:440-445.)

Section: Dental Anomalies Associated With Infraocclusionmentioning

confidence: 99%

Increased Occurrence of Dental Anomalies Associated with Infraocclusion of Deciduous Molars

Shalish¹,

Peck²,

Wasserstein³

et al. 2010

“…Both agenesis and clefting have been shown to be associated with the MnP2 malposition anomaly. 1,15 Results of this work, along with results from Shalish et al, 1,15 associate the MnP2 angulation anomaly with PDC, agenesis, and clefting, suggesting the MnP2 anomaly is a variable in a genetically related group of dental anomalies likely to be associated with MSX1 mutations. It is likely that the MnP2 anomaly may ap-pear in combination with any other of these inter-associated anomalies (eg, infraocclusion, mesially ectopic maxillary first molar, tooth transposition, tooth rotation, tooth size reduction, peg-shaped maxillary lateral incisor), perhaps because all of these anomalies are caused by the same mechanism.…”

Section: Discussionmentioning

confidence: 90%

Malposition of Unerupted Mandibular Second Premolar in Children with Palatally Displaced Canines

Shalish

Chaushu

Wasserstein

2009

Self Cite

Objective: To test the hypotheses that (1) the distal angulation of unerupted mandibular premolar (MnP2) is significantly greater in children with palatally displaced canines (PDC) than in those in a control sample; and (2) delayed tooth formation is significantly more frequent in children with both malposed MnP2 and PDC than in children with PDC only. Materials and Methods: We examined retrospectively panoramic radiographs from 43 patients with PDC who had no previous orthodontics. A control sample consisted of age-and sex-matched patients. The distal angle formed between the long axis of MnP2 and the tangent to the inferior border was measured. Dental age was evaluated using the Koch classification. Results: A significant difference was observed between the mean inclination of the right side MnP2 in the PDC group (75.4 degrees) and that of the control group (85.8 degrees). This difference was highly statistically significant (P Ͻ .0001). The same evaluation was carried out for the left side, with similar results. The average dental age was found to be delayed in patients who showed both abnormalities (malposed MnP2 and PDC) compared with patients who showed the PDC anomaly only. Conclusion: Both hypotheses are retained. Statistically, PDC and MnP2 malposition are significantly associated suggesting a common genetic etiology, despite taking place on opposite jaws. While the presence of PDC or MnP2 anomaly has been associated with a delay in tooth formation, we find the presence of both anomalies to show a more profound delay. Our findings suggest a delay in tooth formation as a possible common genetic mechanism for these 2 malposition anomalies. (Angle Orthod. 2009;79:796-799.)

“…Shalish et al 2,17,18 noted that among populations of European ethnicities, significant distal inclination of the unerupted MnP2 is found not only in cases of unilateral MnP2 agenesis, but also among individuals having cleft lip/palate and palatally displaced canines.…”

Section: Discussionmentioning

confidence: 99%

Mesiodistal inclination of the unerupted second premolar in the mandible of Japanese orthodontic patients with incisor agenesis

Kure

Arai

2015

Objective: To elucidate the mesiodistal inclination of the unerupted mandibular second premolar (MnP2) in cases of mandibular incisor (MnIc) agenesis and unilateral MnP2 agenesis. Materials and Methods: Twenty-two cases of unilateral MnP2 agenesis (MnP2 agenesis group) and a control group (control group A) of 22 cases without permanent tooth agenesis excluding third molars were selected. Thirty-six cases of MnIc agenesis (MnIc agenesis group) and another control group (control group B) of 36 subjects were also selected. Mesiodistal inclination of the unerupted MnP2 on the panoramic X-rays was measured according to the distal angle and premolar-molar angle using the methods of Shalish et al. and Baccetti et al., respectively. Differences in mean values of the angular measurements between agenesis groups and corresponding controls were investigated (unpaired t-test). Results: In the MnP2 agenesis group, the mean distal angle decreased 12.3u and the mean premolar-molar angle increased 13.3u for the MnP2 compared with control group A (both P , .001). In the MnIc agenesis group, no significant differences in the means of those angles for the MnP2 were found when compared with control group B. Conclusion: In Japanese orthodontic patients, there is a relationship between unilateral MnP2 agenesis and the mesiodistal angulation of the unerupted MnP2. However, no significant relationship was observed between MnIc agenesis (which relationship is often seen in Asian populations) and the position of the unerupted MnP2. These results suggest that different genetic factors are involved in MnP2 agenesis and MnIc agenesis. (Angle Orthod. 2015;85:949-954.)