Comparison of the dental anomalies found in maxillary canine-first premolar transposition cases with those in palatally displaced canine cases

Comparisons of Dental Anomalies in Orthodontic Patients with Impacted Maxillary and Mandibular Canines

To assess the presence and possible associations between the type of dental anomalies and maxillary and mandibular canine impactions in orthodontic patients treated for canine impaction, panoramic radiographs of orthodontic patients treated for canine impaction were assessed for the presence of associated dental anomalies. A random sample of orthodontic patients without canine impaction matched for age and gender served as controls. Descriptive and exact inferential statistics were implemented in order to assess potential associations between canine impaction and dental anomalies. A total of 102 orthodontic patients with 70 maxillary (MaxCI) and 32 mandibular (ManCI) canine impactions were assessed. The control group included 117 orthodontic patients. Dental anomalies were present in more than 50% of patients with impacted canines and in 20% of the controls. Tooth agenesis was significantly more common in the MaxCI group when compared to the ManCI group, while supernumerary teeth and canine transmigration were registered more often in the ManCI group. When compared to the control group, peg-shaped maxillary lateral incisors and tooth agenesis were significantly more prevalent in the MaxCI group, while canine transmigration, supernumerary teeth, the agenesis of mandibular incisors and tooth transpositions were significantly more prevalent in the ManCI group. The impaction of other teeth was significantly more common in both canine impaction groups when compared to the controls. The prevalence of dental anomalies in orthodontic patients with impacted canines was higher than in orthodontic patients without canine impaction. Different types of tooth anomalies were found in the MaxCI and ManCI groups.

Prevalence of maxillary canine impaction in skeletal Class III malocclusions compared to Class I malocclusions

Background

The aim of the present investigation was to evaluate if an orthodontic population of Class III malocclusion patients shows a different prevalence of maxillary canine impaction than Class I subjects.

Material and Methods

Fifty-eight subjects were retrospectively selected and assigned to the Class I group (n= 32) or the Class III group (n= 26), depending on the ANB and WITS values. Lateral cephalograms were used to collect angular and linear measurements that described the skeletal and dental maxillary features of the subjects, while orthopantomography was used to assess the impaction or the correct eruption of the maxillary canines. An independent samples T-test or a Mann-Whitney U-test was used to compare the cephalometric values between the two groups, while a chi-squared test was used to evaluate the distribution of maxillary canine impaction between the two groups.

Results

No statistically significant difference was found for the cephalometric variables, and the frequency of canine impaction showed no difference between the Class III and Class I subjects.

Conclusions

Patients with skeletal Class III malocclusions did not show a different prevalence of canine impaction; therefore, such skeletal features cannot be used as a diagnostic aid for assessment of the risk of maxillary canine impaction. Key words:Skeletal Class III, Angle Class III, maxillary canine impaction, tooth impaction.

Third molar tooth agenesis and pattern of impaction in patients with palatally displaced canines

OBJECTIVES

To investigate the association between third molar agenesis and pattern of impaction, missing teeth, and peg-shaped lateral incisor with palatal canine displacement (PDC).

MATERIALS AND METHODS

The pretreatment orthodontic orthopantomograms of 438 patients (122 males and 316 females) diagnosed with PDC were included. A total of 338 patients with normally erupted canines who had a preexisting radiograph as part of their orthodontic treatment (125 males and 313 females) served as controls. Orthopantomograms were evaluated for missing third molars, third molar eruption status, and type of impaction, third molar spaces, third molar width, and angulation.

RESULTS

In the PDC group, at least one third molar was missing in 48% and 19% in the upper and lower arches, respectively. Also, 38% and 67% of PDC patients had at least one third molar impaction in the upper and lower arches, respectively. The difference between the PDC and control groups was significant for both missing and impacted third molars ( P < .001 for each). The most common type of third molar impaction in the upper arch was vertical and distoangular in the PDC and control groups, respectively. Upper and lower third molar width and spaces were reduced in PDC patients when compared with the control group ( P < .001). In PDC patients, missing teeth and peg-shaped lateral incisors were recorded in 5.6% and 9.1%, respectively.

CONCLUSIONS

PDC patients showed a high prevalence of third molar agenesis and impaction. Upper and lower third molar width and space were reduced in the PDC patients. There were no significant associations between tooth agenesis (other than third molars) and the PDC anomaly.