Renato Mazzonetto

Complications of intraoral donor site for bone grafting prior to implant placement.

Purpose:The purpose of this prospective study was to evaluate the morbidity and the major complications of intraoral donor sites for bone grafting prior to implant placement. Materials:The records of 104 consecutive patients with indication for bone grafting prior to implant installation treated at Piracicaba Dental School by the Department of Oral and Maxillofacial Surgery, from June 2001 until June 2003, were reviewed. Results:One hundred three surgical procedures were realized, in which 40% were harvested from mandibular symphysis, 28.8% from mandibular ramus, and 31.2% from maxillary tuberosity. Prevalence of complications among intraoral donor sites was more significant after harvestingvesting the mandibular symphysis. The major complication and discomfort reported by the patients was sensory deficit in lower lip and mental area. It was noted that 16% harvesting procedures involving symphysis and 8.3% involving the mandibular ramus area reported some sensory deficit. No complications were found involving the maxillary tuberosity. Conclusion:Complications and morbidity were smaller in the ramus than in symphysis, and temporary sensory disturbances were the most common complications, noted in both symphysis and ramus areas.

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.

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.

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.

Lingual cyst with respiratory epithelium: a histopathological and immunohistochemical analysis of two cases

Cysts of the tongue are rare, usually derived from epithelia of the embryonic gastrointestinal and respiratory tracts, and classified according to the predominant epithelium lining. These cysts are usually discovered during infancy, more frequently in males, but they may not appear until well into adulthood. The authors report two lingual cysts lined mainly with respiratory, and focally by squamous, epithelium. Periodic acid-Schiff and mucicarmine staining revealed focal positivity in intracystic mucoid material and goblet cells. Immunohistochemical analysis with vimentin, cytokeratins (AE1/AE3, 34betaE12, CK1, CK5, CK6, CK7, CK8, CK10, CK13, CK14, CK16, CK18, and CK19), E-cadherin, beta-catenin, and epithelial membrane antigen showed a similar profile of normal respiratory epithelium, suggesting well-differentiated states. Owing to their controversial origin, these cysts should be named descriptively, as suggested by Manor et al., as lingual cysts with respiratory epithelium.

Bone repair is influenced by different particle sizes of anorganic bovine bone matrix: a histologic and radiographic study in vivo.

PurposeThe aim of this study was to analyze histologically and radiographically the influence of particle size of anorganic bovine bone matrix (ABBM) on bone repair. Materials and MethodsFour calvarial defects of 8 mm each were prepared in 18 adult New Zealand rabbits. The defects were then filled with either particulate autogenous bone (control group) or ABBM of large, medium, and small size granules. The animals were sacrificed at 15, 30, and 60 days after surgery. The samples were radiographically examined before being submitted to histological processing. ResultsAutogenous bone showed a slight radiopacity at the beginning, which was increased at the final period, being very similar to the adjacent bone tissue. The large and medium size ABBM particles maintained the same radiographic behavior, showing a radiolucent area in the central portion of the defect at 60 days. ABBM of small size granules showed a slight radiolucity at the initial period, which was increased at the subsequent periods. More intense bone formation occurred in the control group (autogenous bone). All 3 particle sizes of the biomaterial resulted in inflammatory infiltration at 15 and 30 days. ABBM of small size granules lead to a greater amount of osteoid tissue, and the particles were almost totally reabsorbed within 60 days of implantation. ConclusionsAutogenous bone graft lead to the best result in terms of bone defect repair; ABBM of large and medium size granules are not totally reabsorbed at the observed period; ABBM of small size granules was more intensively reabsorbed and led to a greater osteoid tissue formation when compared to the medium and large ABBM granules.

Mineralized Tissue Formation Associated With 2 Different Dental Implant Designs: Histomorphometric Analyses Performed in Dogs

The clinical success of dental implants might be associated with such factors as installation technique, implant shape, size, material, and screw threads. Therefore, the aim of this study is to analyze mineralized tissue formation on the screw threads of conical and cylindrical dental implants. This study includes 7 beagle dogs that had the lower premolars extracted. Three months after bone and soft tissue repair, 2 different designs of dental implants (1 conical and 1 cylindrical) were installed in each hemimandible using a nonsubmerged technique. Both implants when installed had different shape and thread, as revealed by scanning electron microscopy. Six weeks after implant installation, animals were killed and submitted to histomorphometric analysis. Cervical, middle, and apical areas were analyzed. Statistical analysis was carried out using Student t test at a significance level of P < .05. Statistically significant differences were not found between the conical and cylindrical implants. The conical implants presented fewer threads, a smaller area, and more bone formation when compared with the cylindrical ones, without significant differences (P  =  .1226). The highest values concerning bone formation were observed for the cervical area (P  =  .4005), and the lowest for the apical area (P  =  .1899); however, no statistically significant difference was observed. In conclusion, no statistically significant difference was observed in thread bone formation between the cylindrical and conical implant designs when placed using the nonsubmerged technique.

Análisis Histológico del Proceso de Reparación en Defectos Óseos: Reconocimiento de Defectos Críticos

Los procedimientos quirurgicos que envuelven la rehabilitacion de la region maxilofacial requieren frecuentemente el uso de injertos para la reconstruccion de de deformidades congenitas o adquiridas. De esta forma, defectos oseos pueden clasificarse como criticos o no criticos. En esta investigacion fueron utilizados 6 canes machos realizando 2 defectos bicorticales de 8mm de diametro en la calota craneal de cada animal; el relleno de las cavidades se realizo como grupo 1 con coagulo sanguineo y grupo 2 con hueso autogeno en particulas. A traves de un an analisis histologico descriptivo se observo en el periodo de tres semanas de sacrificio que el grupo 2 fue el unico en presentar regiones de aposicion de nuevo tejido oseo. En el periodo de 6 semanas el grupo 2 presento particulas de hueso autogeno utilizadas para el relleno en estado de reabsorcion avanzada en ausencia de los bordes nitidos entre el defecto y el hueso preexistente. De este modo se concluye que el metodo que auxilie en el proceso de reparacion tecidual como los injertos oseos autogenos, estan indicados en la recuperacion de defectos criticos, iguales o mayores que 8mm.

Prospective Clinical Assessment of Morbidity After Chin Bone Harvest

AbstractThe aim of this prospective research was to assess soft tissue morbidity in the symphyseal region after bone graft harvesting. Thirty patients, with average age 45 years, underwent symphyseal bone graft harvesting followed up for a period of 12 months. Follow-up involved neurosensory testing of 2-point discrimination, static light touch, brush directional stroke, pinprick, and thermal discrimination to cold and hot; the statistical analysis was performed using McNemar test and Friedman test with P < 0.05. The results showed that 50% of patients had postoperative morbidity in the first month after surgery showing statistical positive relation with surgery (P < 0.05); at 6 months, this situation diminished to 23%, and at the end of the monitoring period (1 year); the neurosensory tests revealed no persistent morbidity. In conclusion, all neurosensory tests revealed high morbidity in the first month with total resolutions at 1-year follow-up; however, this complication associated to surgery is indispensable to discharge the patient properly.

Distracción osteogénica alveolar: una alternativa en la reconstrucción de rebordes alveolares atróficos: Descripción de 10 casos

espanolLa distraccion osteogenica alveolar (DOA) es un metodo alternativo para la reconstruccion de rebordes alveolares atroficos que ofrece un resultado previsible y que disminuye los tiempo de espera entre la reconstruccion del reborde alveolar atrofico y la colocacion de los implantes oseo-integrados, en comparacion con los metodos tradicionalmente utilizados. Fueron atendidos 10 pacientes que presentaban deficiencia de reborde alveolar mandibular y/o maxilar por medio de distraccion osteogenica, utilizando un dispositivo yuxtaoseo (Conexion Implant System® - SP-Brasil). Todos los pacientes fueron atendidos de forma ambulatoria, bajo anestesia local y sedacion conciente, comenzando la activacion del dispositivo a los 7 dias posteriores a la instalacion, con un patron de activacion de 1 mm diarios hasta alcanzar la altura osea deseada. Posteriormente se aguardaron 10 semanas como parte del periodo de consolidacion osea y se realizo la colocacion de los implantes oseointegrados y local y el retiro del dispositivo de distraccion, pudiendose comprobar clinica y radiograficamente la ganancia de la altura y volumen oseo necesario para la rehabilitacion por medio de implantes. EnglishThe alveolar distraction osteogenesis is an alternative method for the reconstruction of atrophic alveolar ridges with success, that decrease the time of wait between the reconstruction of the alveolar ridge and the placement of the osseointegrated implants in comparison with the traditionally used methods. 10 patients that presented deficiency of the alveolar ridge in the maxilla and/or mandible were assisted by means of distraction osteogenesis, using a juxtaosseous device (Conexion Implant System® - SP-Brazil). All the patients were assisted of form ambulatory, under local anesthesia and conscientious sedation, beginning the activation from the device 7 days later to the installation, with a pattern of activation 1 mm diary until reaching the wanted bony height. Later on 10 weeks like part of the period of bony consolidation were awaited and one carries out the placement of the osseointegraded implants and the retirement of the distraction device, being able to check clinic and radiographic the gain of the height and necessary bony volume for the rehabilitation by means of implants.