Teeth type may affect the

Teeth type may affect the percentage of tooth structure removal and this in agreement with Hussain et al. Amount of teeth weight before preparation may affect the percentage of tooth structure removed.
The guidelines that were used for the tooth preparations were for ideal situations. Only the specific requirements of the restorative material were considered as a factor for tooth structure removal. In vivo, the health of the tooth, esthetics, function, tooth orientation, and reconstruction of the occlusion may affect the final preparation design.
Clear templates and periodontal probes were used to control the tooth preparations. Each tooth was embedded beyond the CEJ; thus, adapting the template to the tooth was challenging. As a result, the template was constructed on a duplicate purchase buprenorphine hydrochloride of each tooth with vent holes near the tooth surface, and the duplicate cast was subsequently sectioned to retrieve the template. Clinically, the preparation should be guided by a template that is custom-fabricated and is based on the diagnostic wax-up. This procedure economizes the removal of tooth material and ensures a consistent thickness of the final restorative material. An advantage of a clear template over the silicon index is that all of the tooth surfaces can be seen and measured through the template, and the clear template can be used to fabricate the temporary restoration.

Within the limitations of this study, the following conclusions can be drawn:

Conflict of interest

Tooth impaction is a pathological condition in which a tooth fails to erupt to the normal functional position within the expected time; due to lack of space, or physical barriers. Third molar is the most commonly impacted tooth in the oral cavity and accounts for 98% of all impactions. The frequency of third molar impaction varies substantially among different populations; and was reported to range from 18% to 70%. This can be attributed to racial variation in the pattern of facial growth and jaw and tooth size, which are crucial determinants of the eruption pattern.
The removal of impacted third molars is one of the most common procedures performed in the speciality of oral and maxillofacial surgery, since these teeth are often associated with pathological conditions including pericoronitis, periodontitis, cystic lesions or root resorption.
Third molar extraction can be performed using elevators and/or forceps, or may require a surgical intervention. The latter is associated with increased risk of postoperative complications such as alveolar osteitis (dry socket), haemorrhage, nerve injuries, or in rare occasions, a fracture of the mandible. However, the majority of these problems can be anticipated preoperatively with adequate clinical examination and dental radiographs. Panoramic radiograph (OPG) is considered the technique of choice to evaluate the status of impacted third molars. It is used to assess the angular position of impaction, level of impaction and amount of covering bone. In addition, panoramic radiograph is a reliable tool to evaluate the relationship between inferior alveolar canal and third molars.

Materials and methods
This study was undertaken on a group of patients attending a private dental clinic in Benghazi between 2008 and 2013. A total of 300 OPGs comprising 1200 third molar were selected for evaluation. The age range of subjects was 20–54 years. Records of the following cases were excluded from the study:

Among the 300 OPGs evaluated, 156 (52%) were of males and 144 (48%) were of females, the mean age of the study group was 29±6years. Fig. 1 shows the distribution of subjects by the total number of impacted third molars.
From the 1200 third molars reviewed, 843 were classified as impacted and were evaluated in base study. Of the 843 impactions, 371 (44%) were in the maxilla and 472 (56%) were in the mandible. Impacted third molars were 1.2 times more likely to occur in the mandible than in the maxilla. There was no significant difference between the right and left sides in both arches (P=0.685). Moreover, the total number of impactions was not significantly different between the sexes (P=0.256). The distribution of impacted third molars by arch, sex and side is shown in Table 1.