Guenter Russmueller

Maxillomandibular advancement for treatment of obstructive sleep apnea syndrome: a systematic review.

PURPOSE To perform a systematic review of the published data concerning maxillomandibular advancement for the treatment of obstructive sleep apnea syndrome. MATERIALS AND METHODS A systematic literature search was performed in the PubMed database. Original articles in the English language were reviewed to obtain information about patient data, success rates, and outcome measures. RESULTS The systematic literature search yielded 1,113 citations, of which 101 articles met our inclusion criteria. After a review of the full text, 39 studies were included in the analysis. Most articles were classified as evidence level 4, and 5 met the inclusion criteria for level 2b. The only prospective randomized controlled study had been published in January 2010 and was assigned level 1b. CONCLUSIONS A recommendation grade of A to B was achieved with regard to the levels of evidence-based medicine. Our results have shown that maxillomandibular advancement is the most successful surgical therapy, and the postoperative polysomnography results are comparable to those under ventilation therapy.

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.

Efficient Curing of Vinyl Carbonates by Thiol‐Ene Polymerization

Vinyl carbonates have recently been identified as a suitable alternative to (meth)acrylates, especially due to the low irritancy and cytotoxicity of these monomers. The drawback of some vinyl carbonates containing abstractable hydrogens arises through their moderate reactivity compared with acrylates. Within this paper, we use the thiol-ene concept to enhance the photoreactivity of vinyl carbonates to a large extent to reach the level of those of similar acrylates. Mechanical properties of the final thiol-ene polymers were determined by nanoindentation. Furthermore, low toxicity of all components was confirmed by osteoblast cell culture experiments.

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.

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.

Manifestation of an ameloblastic carcinoma ten years after follicular cyst enucleation in the mandibular ramus

Ameloblastic carcinoma (AC) is a rare tumour which can emerge de novo or from an ameloblastoma. To our knowledge, malignant transformation from an odontogenic cyst into an AC has not been documented yet. This case report describes the manifestation of an AC 10 years after enucleation of a histologically confirmed follicular cyst in the angle of the mandible.

Upregulation of osteoprotegerin expression correlates with bone invasion and predicts poor clinical outcome in oral cancer

OBJECTIVES We aimed to determine the prognostic significance of receptor activator of nuclear factor kappa-B ligand (RANKL), RANK and osteoprotegerin (OPG) in patients with oral squamous cell carcinoma (OSCC). MATERIALS AND METHODS The protein expression of RANKL, RANK and OPG was assessed by immunohistochemistry on pretreatment biopsies of 93 patients with locally advanced OSCC who received preoperative chemoradiotherapy (CRT). The primary endpoint was cancer-specific survival. Secondary endpoints were correlation of biomarkers with bone invasion and pathological tumor response. Kaplan-Meier curves and Cox regression models were used for survival analyses. RESULTS A significantly higher OPG expression was demonstrated in patients with malignant bone invasion and non-responders to CRT as compared to patients without bone invasion and responders (p=0.032 and p=0.033, respectively). Multivariate analysis revealed that higher OPG expression was independently associated with shorter cancer-specific survival (p=0.04). The expression status of RANKL and RANK was not significantly related to clinicopathological characteristics and had no impact on survival of OSCC patients. CONCLUSION Upregulation of OPG expression is associated with bone invasion, poor pathological tumor regression to neoadjuvant CRT, and worse long-term cancer-specific survival in patients with locally advanced OSCC. Our results indicate that OPG may be a novel prognostic biomarker in oral cancer.

Tricalcium phosphate-based biocomposites for mandibular bone regeneration--A histological study in sheep.

The present study investigated the suitability of three different absorbable biocomposites for the repair of critical sized bone defects created at the mandibular angle of adult sheep. Each biocomposite was composed of a three-dimensional individualized polylactide scaffold, containing a tricalcium phosphate biomaterial (chronOS). Either autologous bone marrow (chOS/BoneMarrow) or coagulation factor XIII (chOS/FactorXIII) was added to the biomaterial for osteopromotion. Venous whole blood (chOS/Blood) added to the biomaterial served as a control. A total of 18 adult sheep were used for implantation studies, subdivided into three groups of six animals each. After 12 weeks of observation, the animals were sacrificed and the mandibles were retrieved for qualitative and quantitative histologic assessment within three regions of interest (transitional zone, center, and periphery) throughout the biocomposites. Successful bone regeneration was defined by the absence of scaffold deformation and the presence of new bone formation within the biocomposites. In histomorphometry, only chOS/BoneMarrow showed elevated area fractions of newly formed bone in all regions of interest (transitional zone 50.7 ± 7.5, center 31.9 ± 9.3, periphery 23.1 ± 13.5). This led to preservation of the macroscopic scaffold structure in all specimens. Zero hurdle regression confirmed this by validating the factor biocomposite as significant (p < 0.001) for regeneration success. In our experiment, chOS/BoneMarrow was the only biocomposite passing the hurdle of regeneration in all three regions of interest. In contrast, bone formation was less pronounced and uniform in chOS/FactorXIII and chOS/blood-containing specimens. In these groups, scaffolds showed obvious to significant deformation. Overall, autologous bone marrow showed the most promising results in our experimental setting. As opposed to reports in the literature, we could not confirm the suitability of coagulation factor XIII to promote bone formation, since bone formation rates were comparable only to those of the control venous blood.

3D Printable Biophotopolymers for in Vivo Bone Regeneration

The present study investigated two novel biophotopolymer classes that are chemically based on non-toxic poly (vinyl alcohol). These vinylesters and vinylcarbonates were compared to standard acrylates in vitro on MC3T3-E1 cells and in vivo in a small animal model. In vitro, both vinylester and vinylcarbonate monomers showed about tenfold less cytotoxicity when compared to acrylates (IC50: 2.922 mM and 2.392 mM vs. 0.201 mM) and at least threefold higher alkaline phosphatase activity (17.038 and 18.836 vs. 5.795, measured at [10 mM]). In vivo, polymerized 3D cellular structures were implanted into the distal femoral condyle of 16 New Zealand White Rabbits and were observed for periods from 4 to 12 weeks. New bone formation and bone to implant contact was evaluated by histomorphometry at end of observation. Vinylesters showed similar rates of new bone formation but significantly less (p = 0.002) bone to implant contact, when compared to acrylates. In contrast, the implantation of vinylcarbonate based biophotopolymers led to significantly higher rates of newly formed bone (p < 0.001) and bone to implant contact (p < 0.001). Additionally, distinct signs of polymer degradation could be observed in vinylesters and vinylcarbonates by histology. We conclude, that vinylesters and vinylcarbonates are promising new biophotopolymers, that outmatch available poly(lactic acid) and (meth)acrylate based materials.