Dental Anomalies in Chinese Children with Cleft Lip and Palate

Background: The prevalence of dental anomalies in children with cleft lip and palate (CLP) has been said to be higher than in the normal children; however, such findings have not been expressed for different racial groups. Aim: To determine the prevalence of anomalies in children with CLP and to ascertain if there were any differences between the prevalence figures for CLP and non-CLP children. Design: This is a retrospective study looking at previously collected clinical records. The sample consisted of 231 pairs of age and gender matched CLP and non-CLP southern Chinese aged between 12 and 16 years. The dental records of the subjects were examined to gather data on anomalies of tooth number, size and shape. Results: It was found that 57.6% of the CLP children had hypodontia, 10.0% hyperdontia, 8.7% taurodontism, 0.8% a double tooth, 1.30% dens evaginatus, and 42.4% had microdontia in the permanent dentition. The CLP subjects had a statistically higher prevalence of hypodontia (p<0.001), supernumerary (p<0.01) and microdontia (p<0.001) than the non-CLP subjects. More CLP children, were found to have one to three types of anomalies, than the non-CLP children (p<0.001). Conclusion: This group of Chinese CLP children demonstrated a higher prevalence of dental anomalies than the non-CLP children. *Corresponding author: Hai Ming Wong, Department of Paediatric Dentistry, Faculty of Dentistry, The University of Hong Kong, Floor 2A, The Prince Philip Dental Hospital, 34 Hospital Road, Hong Kong, Tel: +852 2859 0261; Fax: +852 2559 3803; E-mail: [email protected] Received December 19, 2011; Accepted March 26, 2012; Published March 28, 2012 Citation: Wong HM, Lai MC, King NM (2012) Dental Anomalies in Chinese Children with Cleft Lip and Palate. Dentistry 2:127. doi:10.4172/2161-1122.1000127 Copyright: © 2012 Wong HM, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Introduction It has been reported that patients with cleft lip and palate (CLP) exhibit a higher frequency of dental anomalies than non-cleft subjects [1-7]. These dental anomalies can be numerical [8,9] or morphological [10]. However, any association between dental anomalies and the presence of clefts is poorly understood. Nevertheless, a direct relationship between the cleft formation and formation of the teeth, irrespective of the genetic predisposition and severity of the cleft type (i.e. unior bi-lateral) has been identified [11]. The frequency of dental anomalies among CLP subjects has been found to be higher than in their siblings, and non-cleft subjects, which were similar [12]. While familial and sporadic cleft cases show no difference in frequency [13]. However, it is unclear if there is any variation based on the ethnicity. Hypodontia is commonly found in CLP patients and the prevalence ranges from 31.5% to 45.9% [14-19]. The lateral incisor is more often missing in CLP than in non-CLP subjects [20]. No gender difference for the prevalence of hypodontia has been found in CLP subjects [21]. As expected more maxillary teeth than mandibular teeth have been reported missing and the cleft side is most frequently affected; whilst both sides are similarly affected in the mandible [16]. In the non-cleft region, the prevalence of hypodontia is reportedly higher in CLP than non-CLP subjects [3,8,14,16,17,22,23,24]. Although these results are from different populations, the common findings are that the permanent maxillary lateral incisors and the premolars on the non-cleft side, are the teeth that are predominately involved. The incidence of supernumerary teeth is highest in subjects with isolated cleft lip and appears to decrease with the severity of the cleft [14]. The prevalence of supernumerary teeth ranges from 6.7% to 22.2% [16,17,19] which is higher than in non-cleft subjects [20]. There is a tendency for a supernumerary primary incisor to be succeeded by a supernumerary permanent incisor [25]. However, the supernumerary primary lateral incisor can be followed by agenesis of the permanent lateral, or a permanent lateral on either side of the cleft, or a supernumerary tooth [16]. Morphological anomalies are found more often in cleft than noncleft subjects [2,8,10,14,15,26,27]. The frequency of abnormally sized and shaped teeth in CLP subjects, ranges from 35.0% to 49.5% [14,17]. They may be incisal, conical or of an intermediate type [18]. These malformations of the teeth have been considered by many authors to be a microform of CLP presentation [28-30]. The reason for the diminutive teeth is unknown; however, surgery cannot be excluded as a possible aetiological factor. Taurodontism was defined by Holt and Brook [31] as an increase in the pulp chamber at the expense of the root. It is usually more evident in the mandibular molars and the prevalence has been reported to be 28.9% [32]. The prevalence of taurodontism in Chinese subjects is reportedly 65% in females and 36% in males [33]. Taurodontism has seldom been investigated in CLP subjects. Akcam and colleagues [34] reported that 1.9% of the unilateral cleft lip and palate children had taurodontic molars. Double tooth is the anomaly of conjoined teeth, which includes both fusion and germination [35]. The location is commonly unilateral in the mandibular lateral incisor region [35-41]. Fusion is said to be more common than germination [36,37,39,40,42-44]. The prevalence of this anomaly in CLP children has been reported by Pöyry and Ranta [45], who found it to be lower than in the non-CLP subjects. Dens evaginatus is a rare developmental anomaly that is predominately found in mongoloid races with a prevalence of 0.1% to 6.3% [46-48]. The corresponding figure for CLP subjects has been reported to be lower than other dental anomalies [34]. Interestingly