Introduction - Materials and methods - Results - Discussion - References.
A. A. Hamasha,T. Al-Khateeb & A. DarwazehDepartments of Preventive Dentistry and Oral Medicine and Oral Surgery, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan.Introduction.
Dilaceration is a deviation, or bend, in the linear relationship of a crown of a tooth to its root; it is an angulation or sharp curve in the root or the crown of a developed tooth of 908 or more. The aetiology of dilaceration was considered to be due to mechanical trauma to the calcified portion of the tooth during its formation (Kearns 1988, Maragakis 1995). However, current studies support the view that dilaceration may be a true developmental anomaly that is not related to a history of trauma (Andreasen et al.1971, Stewart1978, Chadwick & Millett 1995,White & Pharoah 2000). Dilaceration of a crown can be visually observed in the mouth; however, radiographic examination is required to diagnose dilaceration in the root.
Diagnosing a dilaceration is important during root canal treatment (Chohayeb 1983), extraction (Davies & Lewis 1984) and orthodontic movement (Thongudomporn & Freer 1998). No studies have reported the prevalence of dilaceration in permanent teeth in adults; most of the published articles are case reports of individuals suffering from the condition in specific tooth types.
The purpose of this study was to investigate the prevalence of dilaceration in a group of dental patients and to record the distribution of this condition amongst different types of teeth. Materials and methods.
From a total of 12150 dental records, a random sample of 1166 was chosen from patients who attended the Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan. Exclusion criteria included patients who were less than 18 years of age at the time of radiographic examination, records with poor quality radiographs, records with radiographs of only primary teeth and records without periapical radiographs. The final sample included 814 records. All periapical radiographs in each record were examined to give a total of 1586 films and 4655 teeth.
A single examiner read all radiographs with amagnifying lens and an X-ray viewer. A tooth was considered as having a dilaceration towards the mesial or distal direction if there was a 908 angle or greater along the axis of the tooth or root (White & Pharoah 2000). The long axis was determined using a small ruler, aligned along the pulp of the tooth. Dilacerations towards the buccal or lingual were determined by evaluating the appearance of the apical portion of the root. If there was a round opaque area with a dark shadow in its central region cast by the apical foramen and the root canal gave a ‘bull’s-eye’ appearance, a dilaceration was recorded. The periodontal ligament space around the dilacerated portion appeared as a radiolucent halo (White & Pharoah 2000). All teeth on the periapical radiographs were recorded as dilacerated or not. The examiner re-read a sample of100 periapical radiographs containing three dilacerated teeth 2 months after the first examination and a 100% agreement was obtained. The data were entered and analysed using the computer program Statistical Package for the Social Science (SPSS Inc., Chicago, USA). Results.
Of the teeth examined, 2797 (60.1%) were from males and 1858 (39.9%) from females. Ages ranged between 18 and 69 years with a mean of 25.1 years (SD ј 8.03).
Dilacerations were detected in176 teeth out of a total of 4655 (3.78%).The prevalence of dilaceration amongst different tooth types is presented in Table 1.Mandibular third molars were dilacerated most often (19.2%), followed by mandibular first molars (5.6%). Dilaceration was found in 4.7% of maxillary second premolars and 3.6% of mandibular second molars. Maxillary anterior teeth and mandibular incisors were the least affected teeth, exhibiting dilaceration in approximately 1% of cases.
One hundred and thirty-eight subjects had one or more dilacerated teeth (17%). These were found in 80 (58%) males and 58 (42%) females with no significant difference between the genders (P ј 0.74). Of the 176 dilacerated teeth, 31 (18%) were unerupted and 145 (82%) erupted.
Table 1. Distribution of the teeth examined with the prevalence of dilaceration amongst different tooth types.Discussion.
Using periapical radiographs is considered the most appropriate method to diagnose unextracted dilacerated teeth (White & Pharoah 2000). The periapical radiographs used in this study were taken for a variety of purposes including full mouth dental screening and diagnosis of dental problems. Not all records were fully dentate patients, nor did all records contain full mouth radiographs. There is no reason to believe that those Jordanian dental patients are different from other Jordanian adults.
In reviewing the literature, few articles reported the presence of dilaceration and most were case reports of dilaceration in primary or permanent teeth. This study is the first to describe the prevalence and distribution of dilaceration amongst different types of teeth.
There is controversy about the aetiology of dilaceration. Some reports support the view that dilaceration is due to previous trauma. Most of these reported cases presented the condition in anterior teeth that are generally more prone to trauma. However, one report questioned the aetiology of dilacerations and did not support the belief that trauma was the major aetiologic factor (Anderson et al. 1971). In another study (Stewart 1978) of 41dilacerated teeth, no history of trauma was noted in 29 cases. In two other case reports of dilacerated teeth in the mandible (Feldman 1984, Chadwick & Millett 1995), no history of trauma to the lower labial segment was found. In a recent textbook of Oral Radiology, dilaceration was described as a dental anomaly and not a sequel of trauma (White & Pharoah 2000). This study supports that view, since most of the dilacerated teeth were in the posterior region, which is not prone to direct trauma.
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Feldman BS (1984) Tooth with a 'tail'. A case report of a dilacerated mandibular incisor. British Journal of Orthodontics 11, 42-3.
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White S, Pharoah M (2000) Oral Radiology Principles and Interpretation, 4th edn. St. Louis, MI, USA: Mosby, pp.313-4.