Use of resorbable screws for autogenous onlay block graft fixation: a histological analysis in rabbits.

The aim of the present in vivo study is to histologically evaluate and compare the use of resorbable screws based on poly(L-co-D,L lactide) 70:30 for fixation of autogenous bone grafts in rabbit tibiae. As control group, titanium (Ti-6Al-4V Grade V) screws were used. For this purpose, 15 white New Zealand male rabbits, aged 6 months and weighing between 3.8 and 4.5 kg, were used. From each animal, 2 total-thickness bone grafts were removed from the cranial vault: one was stabilized with a resorbable screw while the other was stabilized with a metallic one. Animals were divided into 3 groups, according to the sacrifice period: 3, 8, and 16 weeks postoperatively. After histological processing, cuts were stained with hematoxylin and eosin and submitted for descriptive histological analysis under light microscopy. It was found that the fixation system based on the polymer showed a histological behavior similar to metallic screws. For both groups, the bone graft was incorporated, with the presence of bone formation between the graft and receptor site. In none of the groups were undesirable inflammatory responses or foreign body reactions observed. Based on histological findings and on this experimental model, it is possible to conclude that the internal fixation system based on the poly(L-co-D,L lactide) 70:30 polymer is effective for fixation of autogenous bone grafts, with results that are comparable to the titanium fixation system.

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

PURPOSE: The 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 METHODS: Four 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. RESULTS: Autogenous 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. CONCLUSIONS: Autogenous 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.

Prospective clinical assessment of pulp sensitivity after chin bone harvesting.

PROPOSAL: Evaluate pulp vitality of mandibular teeth after chin bone harvesting. MATERIALS AND METHODS: Thirty patients underwent chin bone harvesting and accompanied for 12 months, being submitted to testing for pulp vitality with Endo Ice refrigerant spray to produce a local temperature of -50 °C. The statistical analysis was executed with McNemar test with P value < 0.05. RESULTS: Results show that canine teeth are most susceptible to alterations; 68.82% (181) of the teeth tested showed no loss of pulp sensitivity to cold 30 days after surgery (P < 0.05), and at the end of the study, that figure had risen to 100% (263) of all teeth included in the sample. CONCLUSIONS: Pulp vitality testing showed that 31.18% (82) of teeth experienced some loss of sensitivity, but by 12 months after surgery, all teeth had recuperated their pulp sensitivity to cold unaided.

Surgical repositioning of osseointegrated malposed dental implant with segmental osteotomy.

After extensive research, the practice with dental implants has been used on a large scale. With the increase in its indications in various local conditions, more complications have been observed. Among these, one of the most frequent is the installation of the implants in a three-dimensional altered position, making the prosthesis and aesthetics more difficult to achieve. For this reason, techniques such as segmental osteotomy have been developed and adapted to implantology to reestablish the adequate position of these implants with correct aesthetic outcome and function. The present clinical report shows the segmental osteotomy technique in a malposed osseointegrated dental position of the upper central incisor with 1-year follow-up.

Evaluation of patients' perceptions of alterations after chin bone graft harvesting.

OBJECTIVE: To evaluate patients' perceptions of alterations occurring after chin bone harvesting. MATERIALS AND METHODS: Thirty patients were evaluated subjectively by visual analog scale-related sensitivity, facial aesthetics, eating, speaking, and lower lip movement, during 12 months. Objective analysis used the static light touch neurosensorial test. The statistical analysis was executed with Friedman test with P < 0.05 for both samples. RESULTS: Subjective analysis revealed no alterations (1) to facial aesthetics, eating, speaking or lower lip movement but sensitivity of the mental region went from a lot of alteration initially (5) to little at the end of the study (3). Objective analysis results showed normal sensitivity (1) in the region after 12 months. CONCLUSION: The discrepancy between subjective and objective analyses may be indicative of the limited precision of clinical testing for subjective impressions assessment.

Prospective clinical assessment of morbidity after chin bone harvest.

The 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.

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.

Reconstruction of severely resorbed maxilla with biodegradable polylactide screws: case series.

PURPOSE: After the loss of natural teeth, bone changes in the jaws begin to take place immediately. Because the alveolar bone no longer responds to stresses placed in this area by teeth and periodontal ligaments, the bone begins to resorb. In such cases, alveolar bone reconstruction followed by implant-prosthetic treatment must be considered to reestablish esthetics and function. The present study was designed to compare and evaluate the effectiveness of titanium screws and absorbable fixation systems for the fixation of autogenous onlay bone grafts in maxillary reconstruction. MATERIALS AND METHODS: A total of 10 consecutive patients with severely resorbed maxillae were referred to the Oral and Maxillofacial Surgery Department at Piracicaba Dental School, Campinas State University (Sao Paulo, Brazil), for oral rehabilitation through implant placement. The bone defects were treated by autologous bone grafting from the iliac crest, which was fixed with absorbable screws. The patients were followed for a minimum of 6 months after prosthodontic work was concluded. RESULTS: The average age of the patients in this study was 46.9 years. Two dental implants were lost during the healing period. Four absorbable screws showed an unusual tissue reaction and were lost, and 90% of patients received the planned fixed prostheses. The implant success rate was 97% at 1 year after prosthesis placement. CONCLUSION: Fixation with absorbable screws has been shown to be safe and predictable. The absorbable screws did not interfere with bone graft healing and dental implant osseointegration.

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 operator's experience with different implant designs, learning curves, or changes in technique and indications for the use of short implants from 1996 to 2004.

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 Tukey's 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.

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.

Oral manifestation of systemic lupus erythematosus: lupus nephritis--report of a case.

Systemic lupus erythematosus (SLE) is a disease of unknown origin that can affect organs and cause severe damage. Lupus is diagnosed through biopsies and laboratory examinations; however, certain clinical characteristics and the presence of lesions can help with early diagnosis and improve the disease prognosis. SLE patients generally receive immunosuppressants that may cause systemic implications---such as suture dehiscence, increased risk of infection, and delayed healing--that deserve specific attention during dental treatment. This article presents a case of a SLE patient with oral manifestations: ulcerative lesions in the mouth and development of lupus nephritis. This article seeks to emphasize the importance of recognizing the lesions related to SLE, which may help the dentist to establish an early diagnosis.

Inflammatory fibrous hyperplasia treated with a modified vestibuloplasty: a case report.

AIM: The purpose of this report is to present a case of surgical and prosthetic treatment of a woman with inflammatory fibrous hyperplasia (IFH) and her evaluation during a six month period. BACKGROUND: IFH is a benign pathology, prevalent in female patients, and principally associated with ill-fitting prosthetic devices in need of adjustment. It is common for patients to require surgical removal of the hyperplastic tissue and fabrication of a new prosthesis. CASE REPORT: A 55-year-old female with a history of smoking presented with a chief complaint of missing the scheduled adjustment of her maxillary complete denture and the presence of moveable tissue under the denture. Surgical excision of the hyperplastic tissue followed with fixation of the prosthesis for six months to guide the healing of the soft tissue and to reshape the contours of the maxillary supporting tissues. SUMMARY: Surgical removal of hyperplasic soft tissue is a routine procedure, and the fixation of the prosthesis for the support of tissue during healing improves intraoral conditions for the fabrication of a new prosthesis in the future.

Patient's perception of the events during and after osteogenic alveolar distraction.

OBJECTIVE: The aim of the study was to evaluate the patient s perception of the events during and after an osteogenic alveolar distraction (OAD) procedure MATERIALS AND METHODS: A total of fifty-five (55) osteogenic alveolar distraction (OAD) procedures were performed in fifty (50) patients, who then were asked to answer ten (10) questions related to the treatment. Six (6) questions made reference to predefined values in a Visual Analogical Scale (VAS), three (3) questions could be answered by a predetermined answer, and only one (1) question had a free answer. RESULTS: In 76% of cases, the patient s description of the sensation felt during the surgery was good and bearable; 84% of the patients didn t feel pain after surgery. 4% of the patients felt pain during the activation period and 58% of the patients described the sensation during the activation period as pressure, felt most commonly, at the end of the period, and for about 20 minutes (66.6 %). In these cases the most frequently used analgesic was Paracetamol. Also, 46% expressed having had some difficulty to activate the device, with 10% of them in need of extra help. The presence of the activation rod caused discomfort in 52%. Finally, 78% of the patients treated with OAD would undergo this procedure again if it was necessary. A bone graft was performed in 27 out of the 50 treated patients, with 70% of them describing the bone graft surgery as more painful than the OAD. CONCLUSION: The OAD technique had a high degree of acceptance among the treated patients, however, some details as the interference of the activation rod continue to disturb them. The acceptance of the OAD technique is much better when compared with bone graft surgery technique as a second treatment.

Evaluation of the bending strength of rigid internal fixation with absorbable and metallic screws in mandibular ramus sagittal split osteotomy: in vitro study.

The aim of this study was to evaluate, in vitro, the bending strength of internal fixation with absorbable and metallic screws in mandibular ramus sagittal split osteotomy in sheep hemimandibles. The screws were inserted as lag screws, with an inverted "L" configuration, and the set was submitted to bending strength tests. The load and displacement of the peak and final load averages were, respectively, 18.45 kgf, 8.19 mm and 14.38 kgf for Group I, and 16.67 kgf, 6.73 mm and 13.98 kgf for Group II. The results were submitted to statistical analysis by Student s t test and by the Pearson correlation analysis. The groups showed no statistically significant differences, indicating the feasibility of both for osteosynthesis in mandibular ramus sagittal split osteotomies.

Treatment of atrophic maxilla with zygomatic implants in 29 consecutives patients.

Atrophic maxilla is a common condition in older population; some treatments are proposed with bone reconstruction or zygomatic implant. Long-term follow up show the efficiencies of zygomatic implant but limited data are associated to consecutive patient. The aim of this study was to evaluate retrospectively the zygomatic implants performed consecutively in 29 patients. Data from clinical records of 29 patients treated with zygomatic implants were analyzed; were include patient with at least 10 month of prosthetic function. Four surgeons realized all surgeries using local anesthesia with a slot technique on local anesthesia; the variables analyzed were implant survival, complications, prosthetic load and satisfaction of patient; data collection was analyzed by descriptive statistic and chi-square test with p<0.05 for significance statistical. 67 zygomatic implants and 84 conventional implants were installed in patients between 35 and 69 year old being 18 (62%) female and 11 (38%) male.The main indication was the case of severe alveolar resorption in 21 cases (72.41%), followed by failures in maxillary reconstruction with bone graft in 4 (13.79%). The implant success was 79.1% and the immediate or delayed load was not associated to statistical difference (p=0.104). The main complication was the loss of osseointegration and mucositis. Analogue Visual Scale (AVS) for satisfaction show acceptable esthetic and function. Finally we conclude that zygomatic implant present adequate survivor and a good response of patient; important complication can be present in a learn curve for this surgery.

TMJ ankylosis after neonatal septic arthritis: literature review and two case reports.

Ankylosis of the temporomandibular joint (TMJ) can be a result of several causes such as trauma, degenerative changes, infection, and space-occupying lesion. When occurring during early childhood, it can result in severe functional disability and facial deformity. Septic arthritis is an uncommon disease associated with systemic and local factors being most commonly caused by Staphylococcus aureus, Neisseria gonorrhoeae, and Haemophilus influenzae. This paper presents two unusual cases of TMJ ankylosis following neonatal infections treated surgically and does a literature review about the topic.

Cephalometric evaluation of surgical mandibular advancement.

The treatment of Class II adult individuals with mandibular deficiency has been the combination of orthodontic treatment and orthognathic surgery. Therefore, a study was conducted in which cephalometric analysis was used to evaluate the influence of dentoalveolar decompensation in Class II patients submitted to orthodontic and surgical treatment for mandibular advancement, by bilateral osteotomy of the mandibular ramus. A sample of 15 leukoderma adult female patients were selected and three cephalometric radiographs of each patient, taken before the orthodontic treatment, before surgery and after at least 6 months postoperatively, were analyzed in a total of 45 roentgenograms. The tracings were made by the manual method and the points were digitalized using software. The results showed that values of SNB increased from 75.6 to 78.6 degrees. The measures BNP and PGNP were reduced from -12.7 to -7.7 mm and -12.7 to -6.6 mm, respectively. For ANB there was a reduction of 3.23 degrees (from 8.1 degrees to 4.9 degrees). Likewise, the values of AOBO were diminished by 6.3 mm (from 7.6 to 1.3 mm), and in the values of OJ there was a reduction of 5.7 mm (from 9 to 3.3 mm). It was concluded that the pre-surgical orthodontic treatment promoted minimal and variable dental and skeletal changes in the final result. The surgical treatment caused significant skeletal changes, especially in the measurements related to the mandible (SNB, BNP, PGNP and SNPM) or indirectly to it (ANB, AOBO and OJ).

Seleccion de osteosintesis en la reconstruccion maxilar con injerto oseo de cresta Iliaca / Selection of osteosynthesis in maxillary reconstruction with iliac crest bone graft

La reconstrucci¢n ¢sea maxilar con injertos libres junto a la osteotom¡a Le Fort I ha sido desarrollada para dar respuesta a las necesidades cl¡nicas funcionales y est‚ticas de los pacientes, debido principalmente a la discrepancia antero-posterior de las maxilas atr¢ficas. Dentro de la t‚cnica, existe necesidad de osteos¡ntesis mediante fijaci¢n interna r¡gida (FIR) que puede ser desarrollada tanto con dispositivos met licos como con dispositivos reabsorbibles. El presente estudio eval£a el uso de ambos materiales de fijaci¢n, relatando las caracter¡sticas, comparaciones y situaciones cl¡nicas que podr¡an estar asociados a su elecci¢n.

The maxillary bone reconstruction with free flaps with LeFort I osteotomy has been developed to give answer to the functional and aesthetic clinical needs of patients, mainly due to the anteroposterior discrepancy of atrophic maxillae. Within the technique, there is need for osteosynthesis though rigid internal fixation (RIS) that can be developed as both metal devices and absorbable devices. This study evaluates the use of both fixing materials, relating the features, comparisons and clinical situations that might be associated with its choice.