Comparison of cone-beam and conventional multislice computed tomography for image-guided dental implant planning.

OBJECTIVES: To compare the accuracy of cone-beam CT (CBCT) and multislice CT (MSCT) with regard to its use in image-guided dental implant surgery in a prospective model based study. MATERIAL AND METHODS: Ten photopolymer-acrylate mandibula models, each with four precise metal reference markers, were scanned with MSCT and CBCT. The six reference distances between the markers were measured by a three-axis milling machine first. The distances were then measured by (1) navigation with the Medtronic StealthStation® TREON™ image-guided surgery system, (2) with the Medtronic planning-tool and (3) on the PC with the Mimics® software. Mean values were calculated for all three methods for CBCT and MSCT and were compared for statistical significance. RESULTS: Of all measurements, 83% of the arithmetic mean values were within the ±0.5 mm range (MSCT 88% and CBCT 78%) and 17% within the ±1.0 mm range (MSCT 12% and CBCT 22%). The absolute difference of the arithmetic mean values showed no statistically significant difference between MSCT and CBCT. The difference of the overall mean values to the reference was 0.43 mm for MSCT and 0.46 mm for CBCT. CONCLUSIONS: The data of our study prove that the application of CBCT for the indicated purpose yielded good results comparable to those of MSCT. All three measuring methods were feasible and accuracy was statistically not different between the data acquired by MSCT and CBCT within the setting of this study.

Impact of elective neck dissection on regional recurrence and survival in cN0 staged oral maxillary squamous cell carcinoma.

To evaluate the impact of elective neck dissection (END) on regional recurrence and survival in cN0 staged patients with maxillary squamous cell carcinoma (SCC). Eighty-six patients with maxillary SCC and clinically staged N0 cervical lymph-nodes were evaluated in this single center retrospective study. Seventy-four of 86 patients were included in this analysis, of which 36 patients were treated with END, 38 without END. Following END, pathohistologically verified regional lymph-nodes in the initially cN0 neck were found in three (8%) patients. In both the +END and non-END group regional recurrences occurred exclusively in patients with T4 primaries. The overall regional recurrence rate was 17% in the +END and 18% in the non-END group, respectively. The 5-year overall survival rate for all tumor stages combined (T1-T4) was 86% in the +END group and 82% in the -END group. Within the patients groups with T4 tumors, 5-year overall survival was 81% for the +END group and 56% for the -END group. Over all tumor stages combined (T1-T4), END did not significantly improve overall survival rates and did not prevent the rate of regional recurrence in cN0 staged patients with maxillary alveolar, gingival and palatal SCC. However, in the subgroup of patients with locally advanced T4 tumors, their seemed to be a clear tendency towards improvement of overall survival in the END group. END can therefore be recommended for these patients.

Functional outcome after surgical treatment of orbital floor fractures.

In the present article, the authors want to present the results of a retrospectively evaluated consecutive series of patients with surgically treated isolated orbital floor fractures (OFF; "blow-out fractures") concerning the functional outcome after OFF and give detailed recommendations based on the clinical and radiological findings. A series of 60 patients with isolated OFF over a 5-year period needing surgically repair at the same institution were evaluated. Patient data were analysed in terms of preoperative and postoperative clinical parameters and radiological findings. The analysed parameters were type of fracture, diplopia, gaze restriction, enophthalmos, materials used for repair, surgical approach and timing of the surgical intervention. Burst type fractures were more often found than punched-out fractures. The most frequently used surgical approach was a preseptal transconjunctival approach. An overall decrease of gaze restriction (93%), diplopia (89%) and enophthalmos (86%) was observed. According to the fracture size, we used Ethisorb patches in smaller fractures and resorbable or titanium meshes or autologous bone in larger fractures in most cases. Patients who underwent surgery more than 7 days after the trauma showed better results with regard to an improvement of diplopia and motility disturbances than patients who were treated immediately. In indicated cases, the surgical repair of OFF leads to very good results if the anatomical and functional properties of the orbit and its contents are respected. The applied strategy and means presented in our study proved of value and can therefore be recommended.

Application of platelet-rich plasma for enhanced bone regeneration in grafted sinus.

PURPOSE: The present study was conducted to evaluate the effect of platelet-rich plasma (PRP) on new bone formation and remodeling after grafting of the maxillary sinus with an algae-derived hydroxyapatite AlgOss/C Graft/Algipore. MATERIALS AND METHODS: Fourteen consecutive patients with severely atrophic maxillae underwent uni- or bilateral grafting of the maxillary sinus with a mixture of collected bone, algae-derived hydroxyapatite AlgOss/C Graft/Algipore (ratio 1:10), and a combined addition of PRP and thrombin (Tissucol Kit; Baxter, Vienna, Austria) to allow for fast clotting. After an average healing period of 7.1 months bone samples were retrieved. Patients from a former consecutive series treated without PRP served as control group. Statistical analysis was done by Welch 2-sample t test and mixed linear model testing. RESULTS: In the coronal specimen portions, mean values for newly formed bone area, biomaterial area and marrow space of 32.2% ± 10.4%, 20.1% ± 13.0%, and 47.7% ± 8.5% were found with PRP, respectively. In the control group the corresponding values were 27.6% ± 13.4%, 20.3% ± 12.9%, and 52.1% ± 9.3%. In the apical specimen portions in the PRP group, the newly formed bone area, biomaterial area, and marrow space was 25.7% ± 15.0%, 23.4% ± 14.9%, and 50.9% ± 12.5%, respectively. The corresponding values in the control group were 17.0% ± 8.6%, 34.5% ± 11.2%, and 48.5% ± 8.5%. CONCLUSIONS: Statistical evaluation of the samples proved significantly better overall resorption of algae-derived hydroxyapatite AlgOss/C Graft/Algipore and increased new bone formation when PRP was used, especially in the apical region.

Endodontic pathogens causing deep neck space infections: clinical impact of different sampling techniques and antibiotic susceptibility.

INTRODUCTION: The aims of the present study were to compare microbial populations in patients suffering from deep neck space abscesses caused by primary endodontic infections by sampling the infections with aspiration or swabbing techniques and to determine the susceptibility rates of the isolated bacteria to commonly used antibiotics. METHODS: A total of 89 patients with deep neck space abscesses caused by primary endodontic infections requiring extraoral incision and drainage under general anesthesia were included. Either aspiration or swabbing was used to sample microbial pus specimens. The culture of the microbial specimens and susceptibility testing were performed following standard procedures. RESULTS: A total of 142 strains were recovered from 76 patients. In 13 patients, no bacteria were found. The predominant bacteria observed were streptococci (36%), staphylococci (13%), Prevotella (8%), and Peptostreptococcus (6%). A statistically significant greater number of obligate anaerobes were found in the aspiration group. The majority of patients presented a mixed aerobic-anaerobic population of bacterial flora (62%). The antibiotic resistance rates for the predominant bacteria were 10% for penicillin G, 9% for amoxicillin, 0% for amoxicillin clavulanate, 24% for clindamycin, and 24% for erythromycin. CONCLUSIONS: The results of our study indicated that a greater number of anaerobes were found when sampling using the aspiration technique. Penicillin G and aminopenicillins alone are not always sufficient for the treatment of severe deep neck space abscesses; beta-lactamase inhibitor combinations are more effective. Bacteria showed significant resistant rates to clindamycin. Thus, its single use in penicillin-allergic patients has to be carefully considered.

Staging and grading as prognostic factors in maxillary squamous cell carcinoma.

PURPOSE: This retrospective study was performed to present our long-term results in the treatment of maxillary squamous cell carcinoma and evaluate especially the influence of T staging and grading on patients' survival. PATIENTS AND METHODS: We performed a retrospective analysis of 93 consecutive patients with alveolar, gingival, or palatal maxillary SCC treated at our clinic with surgical resection and/or radiation therapy. Data were obtained from chart review and patients' records and were analyzed statistically using the log-rank test and Kaplan-Meier survival curves. The male:female ratio was 2:1 and the mean age was 63 years (range 35 to 94 yrs). Most patients showed a T4 stage (66%) and the most frequent staging was T4N0M0 (42%). The most common histopathological grading was G2 (57%), followed by G3 (22%) and G1 (21%). The 5-year overall survival rate was 71%, and the recurrence rate was 37%. Advanced T stage (T4) and grading did not significantly influence the cumulative survival rates. CONCLUSIONS: T-stage and grading do not have a significant impact on patients' long-term survival. The most crucial factor for recurrence prevention and therefore survival are free resection margins.

CROOMA, complication rates of operatively treated mandibular fractures, paramedian and body.

INTRODUCTION: This retrospective study comprises an exploratory analysis of 10 years of surgical treatment of symphysis (S) and parasymphysis/body (P/B). Correlations of complications, as well as dependencies of surgical concepts, are investigated. MATERIALS AND METHODS: All surgically treated patients in the period of 1995 to 2005 with at least one mandibular fracture mesial to the mandibular angle were included in this study. A total of 63 patients (46 men, 17 women) with 63 symphysis fractures were included and 497 patients (369 men, 128 women) with 553 P/B were included; 99.27% (549) of these fractures were included in the study, 4 had to be dismissed because of inconclusive documentation. RESULTS: Of patients with P/B, 96.04% were successfully treated with 1 open reduction, 3.76% had 2, and 0.20% had 3 surgeries. Of the surgically treated patients, 75.77% (416) were completely free of complications, whereas the other 24.23% of the P/B showed 1 or more complications. The main complication was mild nerve damage (24.8%). Osteosynthesis failure rate (OFR) was 2.4% (7 of 298) for 2 miniplates, 5.7% (3 of 53) for 1 tension screw, and 8.4% (9 of 107) for 1 miniplate. Regarding OFR, 2 miniplates showed to be superior in a Fisher exact test (P = .018, adjusted P = .132). Symphysis fractures were completely free of complications in 81.8% and showed 2 major complications, i.e., 1 severe nerve damage and 1 osteosynthesis failure. DISCUSSION: This study has the limitations of a retrospective study. CONCLUSION: A high success rate of open reduction and osteosynthesis with 2 miniplates can be guaranteed.

Antibiotic susceptibility and resistance of the odontogenic microbiological spectrum and its clinical impact on severe deep space head and neck infections.

OBJECTIVE: The purpose of this retrospective study was to identify the major pathogens responsible for deep space head and neck infections and their current resistance to routinely used antibiotics in a university hospital setting. STUDY DESIGN: A total of 206 patients suffering from odontogenic deep space infections were treated at our department by means of surgical intervention and intravenous administration of antibiotics. RESULTS: The predominant bacteria were viridans group streptococci (VGS), staphylococci, Prevotella, Peptostreptococcus, and Bacteroides. In the aerobic spectrum, resistance against clindamycin was found in 18%, against macrolides in 14%, and against penicillin G in 7%. The anaerobes were resistant to clindamycin in 11%, to metronidazole in 6%, and to penicillin G in 8%. CONCLUSION: The high resistance rate for clindamycin and macrolides was especially striking and may necessitate an adaptation of our antibiotic regime in the future.

Closure of oroantral communications with Bichat's buccal fat pad.

PURPOSE: The aim of the present study was to evaluate the use of the pedicled buccal fat pad for the closure of oroantral communications (OACs) and to describe our experience with this surgical procedure. PATIENTS AND METHODS: A retrospective review of 161 patients treated at the University Hospital for Cranio-Maxillofacial and Oral Surgery in Vienna, Austria, from 2000 to 2005, with the diagnosis of an OAC was performed. All defects were closed by application of a buccal fat pad. Data were obtained from chart review, a compiled database, and clinical follow-up and included the location of the defect, the cause of the OAC, the modality of anesthesia, intraoperative complications, any complications during the process of wound healing, and any late adverse effects. RESULTS: The buccal fat pad for closure of an OAC was successfully used in 161 patients at our department. In 12 patients (7.5%), the closure of the OAC was insufficient, and a second operation was necessary. Excluding all severe and complicating cases such as tumor-related defects or previously treated cases, the overall success rate for closure of the OAC was nearly 98%. No late complications occurred, and all patients were free of pain or any limitations after the 6-month follow-up period. CONCLUSIONS: According to the recommendations and anatomic limitations reported in published studies and discussed in the present report, the application of the buccal fat pad is a safe and reliable procedure for closing an OAC.

Surgical treatment of squamous cell carcinoma of the maxilla and nasal sinuses.

PURPOSE: In the treatment of oral squamous cell carcinoma of the maxilla and paranasal sinuses, radical surgery and reconstruction with free flaps is accepted among many clinics. Nevertheless, the treatment protocols vary considerably. This study was performed to present our experience in the treatment of maxillary squamous cell carcinoma with surgical means alone, and to try to identify crucial prognostic factors for the patients' survival. PATIENTS AND METHODS: Thirty-six patients with primary resectable squamous cell carcinoma were included in the study. The mean age was 63 years (43-87 years) and 50% presented in advanced tumor stage (T4). Five patients (14%) already had cervical metastases. All patients were treated by radical surgery alone, and the resulting defects were closed by means of local or free flaps or the use of an obturator, respectively. RESULTS: The overall 5-year survival rate was 64%; the recurrence rate was 33%. Only patients who presented in T3 or T4 stages or had no free resection margins died during the follow-up period. Sixty-nine percent of the patients who died passed away within the first 12 months of follow-up. The 5 patients with cervical metastases received therapeutic neck dissection and showed no regional recurrence. In cases of R1 resection, adjuvant radiotherapy was applied. CONCLUSIONS: The sole surgical treatment of squamous cell carcinomas of the maxillary region led to good results, and can therefore be seen as a valuable strategy. Free resection margins and early detection of the tumor are the most important factors for success.

Maxillomandibular fixation using intraoral cortical bone screws and specially designed metal hooks (Ottenhaken) in the conservative treatment of mandibular fractures.

PURPOSE: The present work evaluated the success of maxillomandibular fixation (MMF) by intraoral cortical bone screws and specially designed metal hooks (Ottenhaken) in nondislocated or slightly dislocated mandibular fractures. PATIENTS AND METHODS: A total of 44 patients who sustained various types of mandibular fractures were treated at the University Hospital for Craniomaxillofacial and Oral Surgery, Vienna Medical School by MMF with Ottenhaken only. The patients were evaluated by preoperative and postoperative radiography, and clinical testing was performed by thermal testing with a cold spray and by assessing the degree of tooth mobility adjacent to the inserted screws. To determine the success of the treatment, various parameters, including screw or hook fracture, screw loosening, local infection of the punctured mucosa, and iatrogenic tooth damage, were considered. RESULTS: The screws and hooks were successfully inserted and MMF was engaged with tight elastics in all cases. The most frequent complication was rupturing of the elastics, necessitating replacement. In 5 patients, local infection of the mucosa around the screw led to severe pain that was treated successfully with analgesics. The screws could be left in place in all 5 cases. Hook fracture and screw loosening each occurred in 1 patient. No iatrogenic injuries of the dental roots were noted. After screw removal, all wounds healed uneventfully. CONCLUSION: The use of intraoral cortical bone screws and specially designed metal hooks (Ottenhaken) for MMF is a useful, valid alternative to arch bars that carries only rare, mild complications.

Postoperative prophylactic antibiotic treatment in third molar surgery--a necessity?

PURPOSE: We evaluated the need for prophylactic postoperative oral antibiotic treatment in the removal of asymptomatic third molars. MATERIALS AND METHODS: In a prospective study of more than 30 months, a total of 528 impacted lower third molars were surgically removed in 288 patients. All patients were referred to our department by a dentist or a general practitioner. No patient showed any sign of pain, inflammation, or swelling at the time of removal. Three groups were established. In the first group, antibiotic treatment with amoxicillin/clavulanic acid as an oral medication was carried out for 5 days postoperatively. In the second group, we used clindamycin. In the third group, the patients received no antibiotic treatment. Clinical and radiologic factors were recorded for each case, and the rationale for assigning the patients to the groups was strictly random. The surgical technique was the same in all cases, and the follow-up period was 4 weeks. Parameters that were evaluated were pain, differences in mouth opening, infection, the occurrence of dry socket, and adverse postoperative side effects. RESULTS: We could not find any significant difference between the 3 groups regarding the evaluated parameters, but in 69.6% of the patients with dry socket, the teeth were partially erupted, which showed a significant difference. CONCLUSIONS: The results of our study show that specific postoperative oral prophylactic antibiotic treatment after the removal of lower third molars does not contribute to a better wound healing, less pain, or increased mouth opening and could not prevent the cases of inflammatory problems after surgery, respectively, and therefore is not recommended for routine use.