*2.3.2 Teeth involved*

When considering individual teeth, some teeth seem to display a greater propensity for asymmetric formation. Ranta reported that asymmetric tooth development occurred most frequently in the upper central incisors followed by the upper and lower premolars, without taking into account peg-shaped teeth and third molars [19, 38]. Harris and Hullings found that second premolars and third molars were more likely candidates for asymmetric formation and these teeth were also more likely to be congenitally missing, with the incisors being excluded in their study [19]. Tan et al. found that the most commonly delayed tooth in the maxilla is the cleft-sided lateral incisors (73.3%), followed by the cleft-sided central incisors (37.3%), while the cleft-sided canines and first premolars were the most frequently affected (21.7%) in the mandible [22].

### *2.3.3 Cleft vs. non-cleft side*

Several authors concur that in both the maxilla and mandible, the cleft side has a significantly higher risk of delayed development of teeth than non-cleft side [18, 20, 22].

### *2.3.4 Maxilla vs. mandible*

Ranta also investigated the difference in incidence of asymmetric tooth development between both jaws. In the cleft palate group, asymmetry occurs with equal frequency in both jaws. However in the cleft lip and alveolus group and the CLP group, asymmetry occurs more frequently in the maxilla [18, 37]. Asymmetric development of teeth was also found to decrease as growth of the crowns and roots progresses [38].

### **2.4 Delayed dental eruption**

Tooth eruption occurs at a precise stage of root development and hence, any delay or asymmetric tooth formation would likely affect the timing and pattern of tooth eruption.

Peterka et al. reported that the deciduous and permanent lateral incisors in the maxillary quadrant with cleft showed the greatest retardation [39]. He also noted delayed eruption of the canine, first and second premolars in the maxillary quadrant with cleft. This coincides with the findings of Carrara et al. who found retarded eruption of the maxillary lateral incisor, cuspid and second premolar on the cleft side [40].

**7**

distribution patterns.

*Dental Development and Anomalies in Cleft Lip and Palate*

**2.5 Aetiology of asymmetric tooth formation and eruption**

Eerens et al. compared 54 children with cleft, 63 children in the sibling group without cleft as well as 250 normal children in the non-sibling control group and found that the cleft group and sibling group showed a significantly higher frequency of asymmetric tooth formation compared to the control group, hence suggesting some common genetic factors for delayed tooth formation and

Another possible reason for asymmetric tooth formation and delayed eruption in CLP patients has also been proposed. The effects of surgical cleft repair could result in damage to the tooth bud, or fibrosis and reduced blood supply to the cleft area [18]. Other etiological factors include lack of space in the cleft area [39] and growth attenuation due to improper nutrition as a result of feeding

The permanent maxillary lateral incisor in CLP patients is a tooth of much interest and has been widely researched on, due to its proximity to the cleft and hence vulnerability to maldevelopment and injury. Disrupted development at the site of the cleft could also be due to altered neurovascular anatomy that could affect the

Some primary maxillary lateral incisors were found to be macrodonts whereas the permanent lateral incisors were microdonts or peg-shaped [43]. It has been reported as the most commonly missing tooth in CLP patients with a frequency

When the permanent maxillary lateral incisor is present in CLP patients, it is usually located on the distal side of the cleft [17, 44, 47–50] and is often reported to be delayed in formation and eruption when compared to the antimeric lateral

Tsai et al. reported on the discrepancy in distribution patterns of the cleftsided maxillary lateral incisors in the primary and permanent dentition [46]. In the primary dentition, the lateral incisor was located most commonly on the distal side of the alveolar cleft (82.4%), followed by missing cleft-sided maxillary lateral incisor (9.9%), one tooth present on each side of the alveolar cleft (5.5%), and lastly, the lateral incisor was located mesial to the alveolar cleft (2.2%). However, in the permanent dentition, the most predominant pattern was the missing cleftsided maxillary lateral incisor (51.8%), followed by the lateral incisor positioned distal to the alveolar cleft (46%), lateral incisor positioned mesial to the alveolar cleft (1.5%) and the least common finding of one tooth present on each side of the alveolar cleft (0.7%). Due to the difference in the distribution patterns between the primary and permanent dentition, the authors proposed that there may be two odontogenic origins (maxillary and medial nasal process) for the maxillary lateral incisors. Failure of fusion between the two processes could have resulted in unequal mesenchymal mass in each of the segment, hence giving rise to different

*DOI: http://dx.doi.org/10.5772/intechopen.88310*

**3. Dental anomalies in CLP patients**

ranging from 19.2–39.3% [3, 17, 44–47].

*3.1.1 Position of cleft-sided lateral incisor*

incisor on the non-cleft side [17, 20, 22, 36, 47, 51].

**3.1 Lateral incisor in the cleft area**

developing tooth germ [42].

clefting [41].

problems [18].

*Current Treatment of Cleft Lip and Palate*

**2.3 Asymmetric tooth formation**

affected (21.7%) in the mandible [22].

*2.3.3 Cleft vs. non-cleft side*

*2.3.4 Maxilla vs. mandible*

**2.4 Delayed dental eruption**

side [18, 20, 22].

progresses [38].

tooth eruption.

A pair of teeth is regarded as developing asymmetrically when the crown or root development of one of the teeth deviated from that of the antimeric tooth by at least one developmental stage. Ranta was one of the earliest authors to report on asymmetric tooth formation [18]. Studies have found that children with CLP had asymmetrical tooth formation that was 3–4 times more common than those of the control group [20, 21, 23]. The only study that did not report such a finding was by

When considering individual teeth, some teeth seem to display a greater propensity for asymmetric formation. Ranta reported that asymmetric tooth development occurred most frequently in the upper central incisors followed by the upper and lower premolars, without taking into account peg-shaped teeth and third molars [19, 38]. Harris and Hullings found that second premolars and third molars were more likely candidates for asymmetric formation and these teeth were also more likely to be congenitally missing, with the incisors being excluded in their study [19]. Tan et al. found that the most commonly delayed tooth in the maxilla is the cleft-sided lateral incisors (73.3%), followed by the cleft-sided central incisors (37.3%), while the cleft-sided canines and first premolars were the most frequently

Several authors concur that in both the maxilla and mandible, the cleft side has a significantly higher risk of delayed development of teeth than non-cleft

Ranta also investigated the difference in incidence of asymmetric tooth development between both jaws. In the cleft palate group, asymmetry occurs with equal frequency in both jaws. However in the cleft lip and alveolus group and the CLP group, asymmetry occurs more frequently in the maxilla [18, 37]. Asymmetric development of teeth was also found to decrease as growth of the crowns and roots

Tooth eruption occurs at a precise stage of root development and hence, any delay or asymmetric tooth formation would likely affect the timing and pattern of

Peterka et al. reported that the deciduous and permanent lateral incisors in the maxillary quadrant with cleft showed the greatest retardation [39]. He also noted delayed eruption of the canine, first and second premolars in the maxillary quadrant with cleft. This coincides with the findings of Carrara et al. who found retarded eruption of the maxillary lateral incisor, cuspid and second premolar on the cleft

*2.3.1 Definition*

Borodkin et al. [21].

*2.3.2 Teeth involved*

**6**

side [40].
