Failure rates and factors associated with infrazygomatic crestal orthodontic implants - A prospective study.

Objective: Infrazygomatic crestal (IZC) implants have gained increased popularity over the past few years. Hardly any studies have been done to assess the rate and reasons for failure of IZCs. This prospective study was planned and designed with the primary objective of assessing the rate of failure of bone-screws (BS) placed in the infrazygomatic crest. In continuation, the secondary objective was to assess the factors that were associated with the failure. Materials and methods: The study was carried out by taking a detailed case history, (age, gender, vertical skeletal pattern, medical history), photographic records, radiographs, and clinical examination of a total of 32 randomly selected. patients of south indian origin who required infrazygomatic implants bilaterally as the choice of anchorage conservation to retract their incisors. All selected subjects were required to take a PA Cephalogram after the implant placement. The age of the patients ranged from 18 to 33 with an average age of 25 years. The patient log was maintained which included the treatment mechanics, status of oral hygiene, stability of implants, time of loading of the implant, presence of inflammation and time of failure of implant. The angulation of implant was measured on a digital PA cephalogram using Nemoceph software. These parameters were examined to evaluate independent and dependent variables using the Chi-Square test and Fischer's exact test. Result: A failure rate 28.1% for IZC placed in the infrazygomatic crest region was observed. Patients with a high mandibular plane angle, poor oral hygiene, immediately loaded implant, peri-implantitis, and severe clinical mobility showed higher failure rates. Variables such as age, gender, sagittal skeletal pattern, length of the implant, type of movement, occluso-gingival position, method of force application, and angle of placement were not significantly associated with implant failure. Conclusion: Oral hygiene and peri-screw inflammation must be controlled to minimize the failure of bone screws placed in the infrazygomatic crest region. Loading of the implant should be done after a latent period of two weeks. A higher failure rate was observed in patients with vertical growth pattern.

Safe sites for buccal shelf bone screw placement in various skeletal malocclusions: A CBCT study.

INTRODUCTION: The mandibular buccal shelf area is an extra-alveolar anchorage site that has high quality and quantity of bone, provides biomechanical benefits and has low failure rates. It is essential to place the implant in the region of bone with optimal thickness. The aim of this study was to determine the suitable site of the mandibular buccal shelf for bone screw insertion at 90 degrees and 30 degrees angles of insertion and various heights, angulations, areas of the buccal shelf in prognathic and retrognathic mandibles, and vertical and horizontal growth patterns. METHODS: In this retrospective study, we evaluated the cone-beam computed tomography (CBCT) images of 48 patients in the age range of 18-30 years, divided into four groups. Seven sectional sites were examined at 3, 5, and 7 mm from the alveolar crest at 90 degrees and 30 degrees. The angulation and area of the buccal shelf were examined. RESULTS: Cortical bone thickness increased distally from the first to the second molar in all four groups. CONCLUSIONS: The preferred site for buccal shelf implant placement was distal to the mandibular second molar. The maximum amount of cortical bone was observed distal to the second molar, 7 mm vertically from the alveolar crest, when the buccal shelf implant was placed at 30 degrees angulation to the long axis of the tooth.

'Comparison and correlation of the maxillary sinus dimensions in various craniofacial patterns: A CBCT Study'.

Background: To compare and correlate the maxillary sinus dimensions and basal bone height among various facial patterns using CBCT for advanced diagnosis and treatment planning in Orthodontics. Methods: 66 CBCT images within age group of 18-30 years were divided into horizontal (Group 1), average (Group 2) and vertical (Group 3) facial growth patterns. Maxillary sinus dimensions were compared and correlated in all three groups. The sinus height and basal bone height were recorded at 3 locations-between 1 st premolar and 2 nd premolar (PM1-PM2), between 2 nd premolar and 1 st Molar (PM2-M1) and between 1 st and 2 nd molar (M1-M2). Results: Overall reduction in sinus height and significantly reduced sinus volume was seen in Group-1. Longest maxillary sinus height in M1-M2 region and shortest in PM1-PM2 region was seen in Group-3. The basal bone height in PM1-PM2 region was significantly longer in Group-3 than in Group-1(p<.05).Shortest basal bone height in M1-M2 region was seen in Group-3. A significant negative correlation was seen between the maxillary sinus height and the basal bone height in Group-1 and Group-3(p<.05). Conclusion: There is a correlation between the maxillary sinus height and basal bone height with that of facial pattern which needs to be considered during orthodontic treatment planning and while carrying out facial growth modification procedures in younger patients.

Optimal sites for mini-implant insertion in the lingual or palatal alveolar cortical bone as assessed by cone beam computed tomography in South Indian population.

OBJECTIVES: To determine the optimal sites of mini-implant placement in the palatal alveolar cortical bone by using cone beam computed tomography (CBCT). SUBJECTS AND METHODS: Cone beam computed tomography records of 60 patients were divided into two groups of equal sizes, based on age and sex. The images were analysed using Planmeca Romexis Software (Version 4.1.2). The measurements were made in axial sections of the maxilla and mandible, at 2, 4 and 6 mm from the CEJ. The optimal sites were defined in terms of (a) Palatal or lingual alveolar cortical bone thickness and (b) Mesiodistal palatal or lingual inter-radicular width. RESULTS: The optimal site for mini-implant insertion, anteriorly, was the canine-lateral incisor embrasure in both the jaws. Posteriorly, the inter-molar embrasure in the mandible and the molar-premolar embrasure in the maxilla were optimal sites. Females demonstrated significantly lesser bone widths in all areas of the maxilla (P < .05) but greater bone thickness in the mandibular regions, as compared to males. The adolescent age group demonstrated a significantly lesser bone thickness but greater mesiodistal widths than the adult population in both the jaws (P < .05). CONCLUSION: The optimal sites for mini-implant insertion were the anterior canine-lateral incisor and posterior buccal inter-radicular embrasures, in both the jaws. Significant differences existed between age and gender groups, which need to be kept in mind while choosing the locations for placing mini-implants.

Third Molar Angulation Changes in Class II Div I Malocclusion Subjects Treated with Extraction of Four Premolars: A Retrospective Study.

AIM: The aim of this study was to assess the changes in maxillary and mandibular third molar inclinations in individuals with class II div 1 malocclusion, before and after orthodontic treatment with extraction of all four first premolars. MATERIALS AND METHODS: This retrospective study consisted of the pretreatment and posttreatment records of 30 patients that were obtained from the archives of the department of orthodontics and dentofacial orthopedics in A B Shetty Memorial Institute of Dental Sciences. The maxillary third molar's relation to the palatal plane and the mandibular third molar's relation to the mandibular plane were measured. The paired t test was used to calculate pre- and posttreatment changes. A value of P < 0.05 was considered to be statistically significant. RESULTS: The maxillary third molars showed a mean correction of 6.15° (P < 0.001) and the mandibular third molars showed a mean correction of 5.10° (P < 0.001). CONCLUSION: Maxillary third molars showed more uprighting when compared to the mandibular third molars and that both maxillary and mandibular third molars showed an improvement in their angulations to their respective planes after extraction of the first premolars. However, the results of the study cannot be analyzed to state if the third molars do become fully functional.