Márcio de Moraes

Influence of Diameter and Length of Implant on Early Dental Implant Failure

PURPOSE To relate diameter and length of implants with early implant failure. PATIENTS AND METHODS Implants with a cylindrical design and surface treatment by removal of titanium via acidification from 3 different manufacturers were used in this study. Two surgical procedures for submerged implants were evaluated--the placement of the implants (first surgical phase) and the procedure for reopening (second surgical phase)--before the installation of the prosthetic system. The length of the implants was classified as short (6-9 mm), medium (10-12 mm), or long (13-18 mm), and the diameter was classified as narrow, regular, or wide. The statistics were computed with SAS statistical software (SAS Institute, Cary, NC). Step-wise and chi(2) analyses were used, in addition to univariate and multivariate logistic regression. RESULTS In this retrospective study, 1,649 implants (807 maxillary and 821 mandibular) were placed in 650 patients (mean age, 42.7 years) in different areas: anterior maxilla (458), posterior maxilla (349), anterior mandible (270), and posterior mandible (551). The early survival rate for all 1,649 implants was 96.2%. Regarding diameter, the largest loss was observed in narrow implants (5.1%), followed by regular (3.8%) and wide (2.7%) implants. Regarding length, the largest loss was observed in short implants (9.9%), followed by long (3.4%) and medium (3.0%) implants. Early loss occurred in 50 implants, 31 (4.3%) of which were installed in anterior areas and 19 (2.8%) in posterior areas. According to step-wise analyses and the chi(2) test, short implant (P = .0018) and anterior installation of implant (P = .0013) showed associations with early loss. CONCLUSION A significant relationship of early implant loss was observed with short implants. No relationships between early loss of implants and the osseous quality or diameter of implants were observed. These findings may be attributed to the operators experience with different implant designs, learning curves, or changes in technique and indications for the use of short implants from 1996 to 2004.

Cephalometric Evaluation of Pharyngeal Airway Space Changes in Class III Patients Undergoing Orthognathic Surgery

PURPOSE The purpose of this study is to retrospectively evaluate pharyngeal airway space (PAS) changes in patients with skeletal Class III deformity who received different skeletal repositioning. MATERIALS AND METHODS A cephalometric evaluation of 45 patients with skeletal Class III deformity was performed. The subjects were divided into 3 groups: group 1 underwent bimaxillary surgery (23 patients), group 2 underwent maxillary advancement surgery (15 patients), and group 3 underwent mandibular setback surgery (7 patients). The PAS was evaluated with the cephalometric analysis of Arnett-Gunson FAB surgery and Dolphin Imaging 11 (Dolphin Imaging and Management Solutions, Chatsworth, CA) preoperatively, 1 week postoperatively, and at least 1 year postoperatively. RESULTS In patients who received bimaxillary surgery, changes in the PAS in the immediate postoperative period were observed. However, long-term measurements at the oropharyngeal level returned to preoperative values. After maxillary advancement, there was an increase in the oropharynx and nasopharynx that remained long-term. In patients who underwent mandibular setback, no changes in the PAS were observed. CONCLUSION In patients who underwent bimaxillary surgery, upper jaw advancement compensated for changes of the PAS brought about by the mandibular setback. Patients who received mandibular setback surgery showed no changes in the PAS, and those who underwent maxillary advancement showed a significant increase of the PAS and that remained stable during the evaluation period. As a consequence, maxillary advancement seems to be the most stable surgical movement in relation to airway dimensional gains.

Incidence and patterns of mandibular condyle fractures

PURPOSE The aim of the present study was to retrospectively evaluate the epidemiologic characteristics of the prevalence, type, and treatment modalities of condylar fractures of the mandible. PATIENTS AND METHODS Data were collected from patients during an 8-year period (1999 to 2007). The data recorded included demographic data, etiology, diagnosis, type, dislocation, use of protective devices, state of the dentition, associated facial and general trauma, soft tissue lesions, treatment methods, and the interval between trauma and treatment. Data analysis included a descriptive analysis, chi(2) test, Fishers exact test, t test, and Kruskal-Wallis test. RESULTS During the 8-year period, 209 unilateral fractures and 54 bilateral fractures were treated, with a male/female ratio of 3.05:1 and a mean age of 28.4 years, for a total of 317 condylar fractures. Male gender was significantly associated with the presence of a condylar fracture (P < .05). The most common cause of condylar fractures was road traffic accidents (57.8%). Of the 317 fractures, 300 were classified as simple fractures, and 249 fractures were not displaced. Protective devices significantly decreased the number of condylar fractures occurring from road traffic accidents (P < .05). Symphysis fractures were significantly associated with both unilateral and bilateral fractures of the mandibular condyle (P < .05). Subcondylar displaced fractures were significantly associated with surgical treatment (P < .05). CONCLUSIONS Young adults were involved in most of the accidents. Road traffic accidents were the main cause of condylar fractures. The mandatory use of safety helmets and seatbelts and education of those using the road are essential to decrease the number of facial fractures.

Comparative Biomechanical and Photoelastic Evaluation of Different Fixation Techniques of Sagittal Split Ramus Osteotomy in Mandibular Advancement

PURPOSE The aim of the present study was to comparatively evaluate the resistance and tension areas created after load incidence in different varieties of sagittal split ramus osteotomy fixation techniques. MATERIALS AND METHODS Fifty synthetic polyurethane hemimandible replicas were subjected to linear loading tests to evaluate 4 fixation techniques of the sagittal split ramus osteotomy using 2-mm system plates and screws. The hemimandibles were fixed with three 90 degrees linear screws, three 60 degrees linear screws, 3 screws in a reversed L arrangement, and one titanium miniplate. Each group was subjected to linear loading using an Instron 4411 servohydraulic mechanical testing unit. The load peak value and peak displacement were measured. Another 4 hemimandible replicas were made of photoelastic resin and subjected to photoelastic analysis after linear loading with a 3-mm displacement. RESULTS The results of the mechanical tests showed statistically significant differences between the fixation groups. The linear 90 degrees fixation and the reversed L arrangement presented with greater loading resistance, followed by the linear 60 degrees fixation and miniplates. In relation to the stress distribution in the photoelastic analysis, the fringes were concentrated near the osteotomy and to the lower part of the mandible in the linear 90 degrees -screw system and reversed L arrangement. In the case of the linear 60 degrees screws, most fringes were located around and between the screws. In the case of the miniplates, the fringes were concentrated around the screws near the osteotomy and more distally. CONCLUSION Under the conditions tested, the linear 90 degrees and reversed L arrangements provided the most favorable behavior.

The Influence of Tobacco on Early Dental Implant Failure

PURPOSE The purpose of this study was to assess tobacco use as a risk factor for early implant failure. MATERIALS AND METHODS To address the research aim, a retrospective study design was used, and a study sample was derived from among patients who had 1 or more implants inserted between July 1996 and July 2004. The main predictor variable was the frequency of tobacco use. The major outcome variable was early implant failure. Appropriate descriptive, bivariate, and multivariate statistics were computed. RESULTS The study sample was composed of 650 patients who had 1,628 implants inserted and were selected for analysis. The early implant loss rates found in the nonsmoking group and the smoking group were 3.32% and 2.81%, respectively. Univariate and bivariate analyses showed no statistical significance for early implant losses associated with the frequency of tobacco use. CONCLUSIONS The results of this study suggest that tobacco use alone cannot be considered as a factor for risk related to early implant failures. Prospective studies are needed to assess the risk of early implant failure in conjunction with smoking.

A Retrospective Analysis of Submental Intubation in Maxillofacial Trauma Patients

PURPOSE The aim of this study was to retrospectively evaluate the frequency, indications, and outcomes of airway management by submental intubation in maxillofacial trauma patients. PATIENTS AND METHODS Data were collected from patients during a 10-year period (1999-2009) from clinical notes and surgical records from each patient using a standardized data collection form that was specifically developed to investigate the epidemiological features of maxillofacial trauma. Data about anesthetic management were assessed. RESULTS During the study period, 3,149 patients, victims of facial trauma, were evaluated: 2,090 patients presented facial fractures; 674 were submitted to surgery under general anesthesia. There were 449 nasal intubations, 204 oral intubations, 6 tracheotomies, and 15 submental intubations. Submental intubation permitted reduction and fixation of all the fractures without the interference of the tube during surgical procedure in all of the patients. There were no intra- or postoperative complications. CONCLUSIONS Submental intubation is a simple, safe, with low morbidity technique for operative airway management in maxillofacial trauma patients when there are fractures involving the nasal region and concomitant dental occlusion disturbances.

Short-Term Outcome of Postoperative Patient Recovery Perception After Surgical Removal of Third Molars

PURPOSE The aim of this study was to depict surgical difficulties related to third molar removal with symptoms and signs presented by postoperative patients, identifying the most frequent occurrences and postoperative complications to prevent them or lessen their intensity. PATIENTS AND METHODS Data were acquired from questionnaires answered by patients and surgeons after surgery. A total of 128 patients participated in this study, answering questionnaires regarding postoperative signs/symptoms on a daily basis for a period of 7 days. Surgeons answered a questionnaire about the surgical procedure. RESULTS Main patient complaints were related to swelling and bad taste/breath, considering that the former was more intense during the first days after operation, and the latter lingered during the 7-day postoperative period of research. Pain was reportedly more intense during the first day after operation and presented continuous reduction throughout the recovery period. Mouth opening (trismus) and eating were the main activities affected by third molar extraction. A positive and significant relevance was only detected regarding surgical duration and difficulties encountered by the surgeon. There was no significant relation between the above-mentioned variables and average and peak pain during the postoperative period. CONCLUSION Results show that during the first postoperative week some patients nay experience quality reduction in their daily activities. Considering that objective (ie, surgery duration) and subjective (ie, difficulties during surgery) indicators were not related to postoperative pain, it was concluded that all patients are entitled to knowing that their lifestyles may be negatively affected by the after-effects, contributing to a better professional-patient relationship.

Histological and histomorphometric analyses of calcium phosphate cement in rabbit calvaria

PURPOSE To assess bone regeneration in critical sized defects in the rabbit calvarium, filled with the bone substitute calcium phosphate cement. MATERIAL AND METHODS Circular bone defects (8mm) were made in both parietal bones of 10 rabbits. One of the defects was filled with the calcium phosphate cement, and the other received autogenous bone harvested from the calvaria. The animals were killed at 3 or 6 weeks (n=5). Data analysis included qualitative assessment of the calvarial specimens and histomorphometric analysis was used to quantify the amount of new bone within the defects. RESULTS The microscopic analysis of the samples showed bone healing with both calcium phosphate cement and autogenous bone graft. Data obtained from the histomorphometric analysis were statistically analyzed using 2-way analysis of variance and the Tukeys test. Data analysis showed that the autogenous bone graft had significantly more new bone compared with calcium phosphate cement at 3 and 6 weeks. Calcium phosphate cement at 6 weeks presented similar results to autogenous bone at 3 weeks. Both treatments presented an increase in bone healing with time. CONCLUSION Treatments allowed bone regeneration that increased with time, however surgical cavities treated with the autogenous graft had more bone formation than those with calcium phosphate cement.

A Comparison of Motorcycle and Bicycle Accidents in Oral and Maxillofacial Trauma

PURPOSE The aim of this study was to present a large series of motorcycle- and bicycle-related traumas to the face in an attempt to identify the injury pattern in motorcyclists and bicyclists. PATIENTS AND METHODS Data were collected from patients during a 10-year period (1999 through 2009), which included demographic data, diagnosis of facial fractures, use of protective devices, dentoalveolar trauma, and facial soft tissue injuries. RESULTS There were 556 patients with bicycle accidents and 367 with motorcycle accidents. Men were involved in 79% (436) of bicycles accidents and 82% (299) of motorcycle accidents. Young male patients were more frequent in bicycle and motorcycle accidents. Two hundred fifty bicyclists showed 311 maxillofacial fractures. Two hundred twenty-one motorcyclists showed 338 maxillofacial fractures. Motorcycle accidents caused multiple fractures in more patients. Seventy-six percent of motorcyclists were using helmets at the time of the accidents, whereas 6% of cyclists were using helmets. Motorcyclists showed a larger number of lacerations, whereas bicyclists showed a larger number of abrasions. Avulsion was the most common dentoalveolar injury for these accident types. Hospital stays were 3.8 days for motorcyclists and 1.3 days for bicyclists. CONCLUSIONS The high-impact collisions typically observed in motorcycle accidents is directly related to larger percentages of soft tissue lacerations and facial fractures. The low-impact trauma that is observed in bicycle accidents is more commonly associated with soft tissue abrasion, hematoma, and dentoalveolar fractures. This stresses the need for compulsory legislation for helmet use with face-guards for cyclists and motorcyclists. It is important to take measures to alert the public regarding the severity of injuries likely to occur in bicycle- and motorcycle-related accidents and ways to prevent them.

A comparative evaluation of the hybrid technique for fixation of the sagittal split ramus osteotomy in mandibular advancement by mechanical, photoelastic, and finite element analysis

OBJECTIVE This study evaluated the mechanical characteristics and stress distribution of the hybrid technique fixation of the sagittal split ramus osteotomy. STUDY DESIGN In the mechanical test, 10 polyurethane replicas of human hemimandibles of each group were submitted to linear loading test. For the photoelastic evaluation, 3 hemimandible replicas of photoelastic resin were subjected to photoelastic analysis. In the finite element analysis, 3 computer models simulated the displacement and the results of maximum principal stress were analyzed. RESULTS The results of this study demonstrated that the fixation technique with 3 bicortical screws presented better mechanical resistance and stress distribution pattern when compared with the hybrid technique that, on the other hand, presents better results in comparison with a miniplate and monocortical screws. CONCLUSIONS The results suggest that the hybrid technique increased the resistance and improved stress distribution of miniplate/monocortical screw fixation, maintaining most of the advantages of this technique.