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Abstract 7.0. Summary and Conclusions The present study was designed in order to evaluate the appropriate positions for mini-implants in maxillary and mandibular dental arches. By the detection the areas of the maximum bone thickness which in return reduce or minimize root damage and increase the stability of the miniimplant. This could be regarded as crucial consideration for implant success and a key to the overall success of mini-implant anchorage. The Cone beam computed tomography images of 80 subjects were evaluated to study three elements; alveolar bone width (bucco-lingual), interradicular bone dimensions (mesio-distal, labial / buccal and palatal / lingual), and cortical bone thickness (labial / buccal and palatal or lingual). These areas could be related to the bone quantity and hence optimal mini- implant placement that influence the mini- implant success. Recent i-CAT acquisition software (version 1.7.7) was used to construct 3D images. Multi-planar reformatting (MPR) images in three orthogonal planes (coronal, sagittal and axial) were projected. Also the images were enhanced by zooming, magnification, adjusting brightness and contrast to reach the highest quality to allow the best assessment. Dimensional measurements were carried out from midline to the second molar for both dental arches (maxillary and mandibular) at the axial window. The slice was adjusted previously in coronal and sagittal windows; at three levels (3, 6 and 9mm from CEJ) respectively. The measurements included the following areas between the teeth: Summary and Conclusions 97 Alveolar process width (bucco-lingual): It was the transverse distance from the outmost point of buccal cortical bone to outmost point of lingual cortical bone. Interradicular distance (mesio-distal): The measurements were taken at the widest distance (labialy\ buccally) and similarly on the palatal \ lingual side. Cortical bone thickness: The distance between the internal and external aspects of the cortex in the middle of the interradicular distance between each two adjacent teeth was measured either (buccally\ labialy) and (lingually\ palatally). The collected data and results were tabulated and graphed. Descriptive statistical analysis was done. The results revealed the followings: At maxilla, bucco-lingual distances decreased as more the cervical the measurement. Also, the inter-radicular distance (mesio-distal) showed the greatest values at the 9 mm level and decreased as the measurement directed into CEJ except in distance between first and second molars. At mandible, the lowest bucco-lingual distance was recorded at most anterior area and more cervical level from CEJ. While, the largest was at reverse the most posterior area at 9mm level. Meanwhile, the highest mesiodistal distance values recorded as the measurements were more distally from the cervical to the apical levels. The cortical bone thickness revealed that the samples had more than 1 mm thickness except palatally between the maxillary central incisors at all the three levels from CEJ. Summary and Conclusions 98 The following conclusions could be drawn from the current study: 1- The selection of the CEJ as a reference point is more reliable than other references for the insertion of the mini-implant to avoid any effect that could be resulted from different periodontal problems on alveolar bone crest. 2- In the anterior maxilla: a) The appropriate and the most suitable locations for mini-implant placement could be between the two central incisors and the central and lateral incisors at level not less than 6mm from CEJ with apical. b) It seems better to incline the mini-implant apically (angulated bath) upon insertion. c) It is better to use a mini-implant with length not exceeding 6 mm in this area. d) Palatally, the insertion of mini-implant between the central incisors should be avoided due to the close relation of incisive foramen which in return is reducing the amount of related bone. 3- In the posterior maxilla: The safer sites for insertion of the mini-implant in this area could be at level not less than 6mm from CEJ: a) Buccally, between canine and first premolar and between second premolar and first molar. b) Palatally, between second premolar and first molar. c) Also, the mini-implant should be inclined apically (angulated bath) upon its insertion as same as anteriorly. d) It is advisable to use the mini-implant with length not exceeding 8 mm. Summary and Conclusions 99 e) The positioning of the mini-implant at the buccal area between first and second molars it is advisable to be inserted either at 3mm or 9mm from CEJ. 4- In the anterior mandible: The safest location could be at level not less than 6mm from CEJ: a) Labially between the lateral incisor and canine. b) The angulated apical bath of insertion is also adivisable. c) The mini-implant length should not exceed 6 mm. 5- In the posterior mandible: a) The optimal site was observed between first and second molars at level not less than 6mm from CEJ. b) The data gained from this research recommended an apical angulated bath upon insertion and the mini-implant length should not exceed 8 mm in this area. |