Prevalence and Distribution of Dental Anomalies among Orthodontic Patients of Kathmandu, Nepal

Introduction: Dental anomalies are commonly seen during regular dental check-up. It occurs due to abnormal morphodifferentiation of teeth during different stages of tooth development. The purpose of this study was to find out the of dental anomalies among orthodontic patients of Kathmandu, Nepal. Materials & Method: A total of 601 patients (242 males and 359 females) of aged 10 to 35 years (mean age= 16.42±3.42 years) who require orthodontic treatment were selected. The patients were assessed clinically and dental panoramic radiographs were evaluated for disturbance in number and other anomalies. A chi-square test was used to determine the difference in the prevalence of dental anomalies between genders and among different classes of malocclusion. Result: The prevalence of dental anomalies was 15.3% that is 92 participants were exhibited at least one dental anomaly among 601 orthodontic patients. Among dental anomalies, hypodontia was the most prevalent (7.48%) followed by hyperdontia (2.99%), microdontia (2.16%), macrodontia (0.66%), transposition (0.66%), taurodontism (0.49%), double teeth (0.33%), amelogenesis imperfecta (0.33%) and dentinogenesis imperfecta (0.16%). The prevalence of oligodontia was 0.33%. There were no statistically significant difference in prevalence of anomalies in between gender and among different classes of malocclusion. Conclusion: Prevalence and distribution of some dental anomalies in orthodontic patients of Kathmandu differed from other studies. Maxillary lateral incisor was the most commonly missing and microdontic tooth. Orthodontists have the responsibility to observe each patient carefully for dental anomalies to correct or improvise this condition without any complications.


INTRODUCTION
Gupta SP, Rauniyar S : Prevalence and Distribution of Dental Anomalies among Orthodontic Patients of Kathmandu, Nepal where Z = 1.96, value of p is taken as 0. 5, q=1-p=0.5, allowable error (d) = 0.04 (96%) and n is required sample size. Based on these parameters, the required sample size was 600.25. Hence, total 601 patients were selected.
Inclusion criteria of this study were patients between 10-35 years of age who came for orthodontic treatment and gave consent to this study and presence of good quality panoramic radiograph and from a single source.
Patients were excluded who had extraction or previous orthodontic treatment, systemic disease or craniofacial anomalies/congenital syndrome.
Ethical approval was obtained from institutional review committee of Institute of Medicine before conducting this study.
After obtaining the informed consent from the patients or their parents, demographic details along with detailed medical, dental and family histories were obtained.
All individuals were evaluated by a single operator (author), and occlusal relationships were evaluated at centric occlusion, which was achieved by asking the subject to swallow and then to bite on his/her teeth together. It was categorized according to Angle In addition to the intraoral examination, dental panoramic radiograph was also evaluated for any dental anomalies. The panoramic radiographs were analyzed by trained observer (author) who followed a pre-established protocol: general observation of the teeth including third molar, followed by a systematic analysis of the erupted and unerupted teeth in each quadrant. A tooth was diagnosed as congenitally missing if the mineralization of its crown could not be identified on orthopantomogram. The evaluation of digital orthopantamogram was carried out on a computer screen with a resolution of 1,280×800 pixels.

Statistical Analysis
Data obtained were transferred to MS-excel sheet.
The data were verified and analysed statistically using SPSS Statistics Version 21.0 (Armonk, NY: IBM Corp.) with confidence level set at 95% (P < 0.05) to test for significance. The prevalence of dental agenesis among orthodontic patients were descriptively analysed. Pearson's Chi-square test was used at 5% significance level to investigate the significance of differences of dental anomalies between gender and among different classes of malocclusion.

RESULT
This study found that among the total of 601 participants, 242 (40.27%) were male while 359 (59.73%) were female ( Fig. 1) and the mean age was 16.42±3.42 years.
The frequencies of selected anomalies, sex distribution and statistical differences between sexes are shown in Table 1. Differences in prevalence rates of each dental anomaly by sex were analyzed by using chi-square test and the related P values were calculated for each anomaly. No statistically significant correlation were found between dental anomalies and patient's gender.

Fig. 2 Distribution of dental anomalies among different malocclusions in orthodontic patients
Class I

Class II
Class III   Hypodontia is defined as the failure of development of one or more teeth, is the most commonly occurring dental anomaly affecting the human dentition.
Oligodontia is defined as missing more than six teeth, roots, with the bifurcation or trifurcation occuring near the apices of the roots. There were 3 (0.49%) cases of taurodontism. There were 2 (0.33%) cases of double tooth, 2 cases of amelogenesis imperfecta and one case of dentinogenesis imperfecta seen in this study.
None of any patient had dentine displasia among orthodontic patients of this study.
This study revealed that malocclusion group had statistically non significant relationship with multiple dental anomalies. This study also showed that dental anomalies as a whole are more common in class-III (19.04%) followed by class-II (15.59%) and class-I (14.97%) malocclusion. The finding of this study

Conflict of interest
The author declares that there is no conflict of interest regarding the publication of this paper. and anodontia is a complete absence of the teeth.
Dental agenesis has been reported to be the most common anomaly in the development of the human dentition and the prevalence of dental agenesis was 7.48 % excluding third molar for both sexes together. The prevalence of supernumerary teeth is between 1 -3% with slight higher rate in Asian population, with a strong predilection for anterior region. 22 Study conducted by Altug-Atac showed a prevalence of 0.36% of hyperdontia. 23 Microdontia refers to teeth which are smaller than normal size. Microdontia was observed in 13 (2.16%) of patients. Most common affected teeth was maxillary third molar followed by maxillary laterals. Microdontia was very common in maxilla compared to mandible. Macrodontia refers to teeth which are larger than normal size. The occurrence of macrodontia (0.66%) was less common than microdontia.
Prevalence rate of transposition of teeth seen in this study was 0.66%. Most common transposition was between maxillary lateral incisor and canine.
Taurodontism is a condition characterized by enlargement of the tooth body at the expense of the OJN