A Non-Invasive and Accurate Measurement of Gingival Thickness Using Cone-Beam Computerized Imaging for the Assessment of Planning Immediate Implant in the Esthetic Zone-A Pig Jaw Model.

INTRODUCTION: The objective of the study is to compare the accuracy of the measurement of gingival thickness using cone-beam computerized tomography (CBCT) with direct clinical measurement on a pig jaw model, aiming to provide an alternate and precise method to aid assessment of the gingival biotype before immediate implant placement at the esthetic zone. MATERIALS AND METHODS: Four pig mandibles were categorized separately into 14 different zones with each prominent tooth cusp as one. A high-resolution CBCT image was taken. Measurement of gingival thickness was performed using computer software and was compared with direct clinical measurements. RESULTS: Intraclass correlation coefficient between clinical and CBCT measurements were 0.995 (pig 1), 0.945 (pig 2), 0.966 (pig 3), and 0.932 (pig 4), which indicated a good match between 2 measuring methods. Independent t test showed no significant difference between 2 independent investigators in all aspect of measurements (P > 0.05). CONCLUSION: Measuring gingival thickness using CBCT is a predictable and accurate method to assess the gingival biotype of a patient, so as to predict the suitability of immediate implantation.

Classification of maxillary central incisors-implications for immediate implant in the esthetic zone.

PURPOSE: This is the first study to analyze the positions and angulations of the central maxillary incisors with reference to the alveolus, providing data for clinicians to achieve good esthetic results for immediate implant placement in the esthetic zone. MATERIALS AND METHODS: A total of 300 cone beam images were selected randomly. Five aspects were measured: the thickness of the palatal and buccal bone at their mid-root and apical level and the apical bone height. A classification was established according to the positions and angulations of the tooth. RESULTS: The data from 170 cone beam images were included in the present study. The mean thickness of the buccal bone at the mid-root level was 0.9 ± 0.4 mm and at the apical level was 2.04 ± 1.01 mm. The mean thickness of the palatal bone at the mid-root level was 3.76 ± 1.37 mm and at the apical level was 8.51 ± 2.54 mm. The mean apical bone height was 9.53 ± 2.76 mm. The proportion of incisors positioned more buccally (type B) was 78.8%, 19.4%, and 1.8% positioned midway (type M) and more palatally (type P), respectively. Regarding the angulation, 49.9% were classified as type 2 (toward buccal), 34.7% as type 3 (toward buccal, with the long axis anterior to the A point), and 15.4% were categorized as type 1 (toward palatal or parallel to the alveolus). CONCLUSIONS: We recommend that clinicians appreciate the socket in 3 dimensions to achieve a good outcome. According to the difficulty of achieving good results, the cases were categorized as levels I to III and recommendations were given.

The usefulness of stereomodels in maxillofacial surgical management.

PURPOSE: This retrospective study aimed to determine the usefulness of stereomodels in various maxillofacial surgical treatments. MATERIALS AND METHODS: A total of 45 stereomodels were evaluated in terms of usefulness from questionnaires completed by 4 groups of subjects: surgeons, postgraduate students, technicians, and patients. These models were categorized into 4 treatment groups: distraction osteogenesis, reconstruction, pathology, and trauma management. The scores of each category were computed and compared among the treatment groups. RESULTS: The stereomodels in this study were used mainly for distraction osteogenesis (53.3%, 24/45 models) and reconstructive surgery (33.3%, 15/45 models). The total mean scores (with 10 being the top score) from the different subjects' assessments were 8.18 by surgeons, 7.80 by postgraduate students, 5.90 by technicians, and 7.70 by patients. CONCLUSIONS: Stereomodels were found by the group subjects to be very useful, particularly for treatment planning and patient communication, as a teaching tool for students, and for prosthesis fabrication.

Prevalence of postoperative complications after orthognathic surgery: a 15-year review.

PURPOSE: This study was conducted to determine the prevalence of postoperative complications after orthognathic surgery and evaluate the use of antibiotic prophylaxis in relation to the infection rate. PATIENTS AND METHODS: All patients undergoing orthognathic procedures between 1990 and 2004 were studied retrospectively by retrieving their individual medical records. Demographic data, intraoperative data (specific orthognathic procedures and duration of operation), and postoperative data (type and duration of antibiotic prophylaxis and presence of postoperative complications) were recorded. Patients noted to have suffered any postoperative complications were studied in detail, and various factors, including gender, age, duration of operation, and use of prophylactic antibiotics, were analyzed using statistical tests in relation to postoperative infection. RESULTS: A total of 2,910 orthognathic procedures were performed on 1,294 consecutive patients in the 15-year period, with 1,070 patients undergoing bimaxillary procedures and 224 patients undergoing single-jaw surgery. The orthognathic surgery-related complication rate was 9.7%, of which 7.4% was related to postoperative infection. Of the cases of infection, 58.3% were acute infection and 41.7% were chronic infection. Patients who received a single preoperative dose of antibiotics had a significantly higher infection rate (17.3%) than those who received postoperative antibiotics for various durations. CONCLUSIONS: The prevalence of infection after orthognathic surgery was relatively low given the complexity of the procedures. No particular orthognathic procedure was more susceptible to infection. A preoperative dose of prophylactic antibiotics together with at least 2 days of postoperative doses was useful in reducing the infection rate compared with only a single dose of prophylactic antibiotics.

A randomized controlled trial of resorbable versus titanium fixation for orthognathic surgery.

OBJECTIVES: To determine any differences in the intra- and postoperative morbidities and complications between resorbable and titanium plating systems for fixation in orthognathic surgery. STUDY DESIGN: This prospective randomized clinical trial was conducted in the Oral and Maxillofacial Surgery unit of the University of Hong Kong. Patients with dentofacial deformities were randomly assigned into the titanium and resorbable fixation groups. Intraoperative data such as the surgical procedures, time for fixing each plate, and number of broken plates and screws were recorded. Subjective and objective parameters related to clinical morbidities were assessed postoperatively. RESULTS: A total of 60 patients with 177 osteotomies were included in this study. Eighty-seven osteotomies fixated with 196 titanium plates and 784 titanium screws were performed in 30 patients, whereas 90 osteotomies fixated with 165 resorbable plates and 658 resorbable screws were done in another 30. The postoperative infection rate was 1.53% (3/196) and 1.82% (3/165) in the titanium and resorbable fixation groups, respectively. These infections were mainly due to loose screws and wound dehiscence. The plate exposure rate was 1.02% (2/196) for the titanium group and 1.21% (2/165) for the resorbable group. The plate removal rate in the titanium and resorbable groups was 1.53% (3/196) and 3.63% (6/165), respectively. Statistically significant difference was shown in the plating time of step (mandibular body) and Hofer (mandibular subapical) osteotomies. There was no significant difference in the subjective clinical parameters such as wound discomfort, clinical stability of the osteotomy segments, palpability of plate, and overall satisfaction of the results between the 2 fixation groups. Similarly, objective parameters including wound dehiscence, rate of infection, plate exposure, occurrence of sinus tract, and palpability assessed by surgeons in both groups also showed no significant difference. CONCLUSION: Bioresorbable fixation devices offer similar function as titanium in fixation for orthognathic surgery and do not impose an increase in the clinical morbidities.