R. Schmelzeisen

Surgical treatment of bisphosphonate-associated osteonecrosis of the jaw: Technical report and follow up of 21 patients

INTRODUCTIONnBisphosphonates are used to reduce skeletal related events in patients with bone consuming diseases such as osteoporosis and bone metastases. However recently there has been an increased awareness of bisphosphonate-associated necrosis of the jaws (BP-ONJ). Many authors propose conservative management in these cases but invariably the problem is not treated successfully allowing the bone defect to worsen. Recently there has been a move to treat this problem surgically. The aim of this retrospective study was to provide a surgical solution for patients suffering from BP-ONJ.nnnMATERIALS AND METHODSnAll patients presenting with BP-ONJ were treated with bone debridement of the affected area and multilayer wound closure. The considered variables were: gender, age, underlying diagnosis, type of bisphosphonate (BP) used, duration of bisphosphonate use, route of administration, location of the osteonecrosis, clinical symptoms, association with dental treatment and surgical outcome.nnnRESULTSnNineteen cases of a total of 21 demonstrated no recurrence of osteonecrosis during follow up (Mean 16 months - Range 12-24 months). One patient with a bilateral defect showed a dehiscence on one side and a small fistula on the contralateral side 6 weeks post-operatively and required revision surgery. Another patient developed a fistula after 4 weeks that was treated successfully with antibiotics and curettage. No patients had evidence of exposed bone, bland mucosa nor pain at the surgical site.nnnCONCLUSIONnThe technique described can be recommended for patients with BP-ONJ if a conservative treatment fails.

MatrixMANDIBLE Preformed Reconstruction Plates—A Two-Year Two-Institution Experience in 71 Patients

PURPOSEnTo evaluate handling, complication rates, clinical and treatment outcomes of the MatrixMANDIBLE Preformed Reconstruction Plates (MMPRPs), in particular with regard to the frequency of fatigue fractures and operative time.nnnPATIENTS AND METHODSnA cohort of 71 subjects with an indication for a load-bearing osteosynthesis of the mandible was enrolled in the present study. The indications for plate use were defects due to tumor, trauma, or osteonecrosis. The outcome variables were fitting accuracy, application time, and postoperative complications, defined as plate exposure, loosening of plates or screws, plate fracture, and orocutaneous fistulas. Additionally, the feasibility of a transoral approach was tested.nnnRESULTSnThe sample included 71 subjects with a mean age of 54.8 ± 15.0 years, including 43 men (60.6%). MMPRPs could be placed in 70 of the 71 patients. In 10 patients a transoral approach for plate application was successfully performed. The mean time investment to contour the plates was 13.1 minutes. The fitting accuracies of the nonbendable sections were satisfying. No plate fracture was observed within an average follow-up period of 11.8 months. Postoperative complications occurred in 19 (27.1%) of the 70 patients. Plate removal was required in 11 (15.7%) of 70 patients.nnnCONCLUSIONSnThe results of the present study suggest that the use of MMPRPs coincides with a reduced operative time and a minimized risk of fatigue fractures. Thus, MMPRPs seem to be a useful standard device in a scope of indications for load-bearing osteosynthesis of the anterolateral division of the mandible, additionally facilitating a transoral approach for application.

Long-term retrospective evaluation of the peri-implant bone level in onlay grafted patients with iliac bone from the anterior superior iliac crest

OBJECTIVEnThe purpose of the present study was to evaluate crestal bone level changes around dental implants after iliac bone augmentation in the long term.nnnMATERIAL AND METHODSnA total of 32 partially edentulous/edentulous patients (mean age, 52 years; range, 22-70 years) and a remaining bone volume of less than 5 mm of the alveolar ridge underwent maxillary or mandibular iliac bone graft augmentation. All patients received spaced standardized radiological examination for evaluation of peri-implant crestal bone loss.nnnRESULTSnThe grafting procedure was successfully performed in all patients. A total of 150 implants were placed. The mean observation period was 69 months (range, 12-165 months; success rate for maxilla, 96%; success rate for mandible, 92%). The mean amount of crestal bone loss after 10 years was 1.8 mm. A significant difference between gender and crestal bone loss was shown, but no influence was found regarding the implant system, diameter of implant, and age of the patients.nnnCONCLUSIONnIn patients with atrophic jaws, a sufficient long-term reconstruction can be achieved with the combination of iliac onlay grafting and dental implants. The results demonstrate high success rates and a stable peri-implant bone level in the long term.

Magnetic resonance imaging of intraoral hard and soft tissues using an intraoral coil and FLASH sequences

ObjectivesTo ascertain the feasibility of MRI as a non-ionizing protocol for routine dentomaxillofacial diagnostic imaging. Wireless coils were used for MRI of intraoral hard and soft tissues.MethodsFLASH MRI was applied in vivo with a mandible voxel size of 250u2009×u2009250u2009×u2009500xa0μm3, FOV of 64u2009×u200964u2009×u200928xa0mm3 and acquisition time of 3:57xa0min and with a maxilla voxel size of 350xa0μm3 and FOV of 34xa0cm3 in 6:40xa0min. Ex vivo imaging was performed in 4:38xa0min, with a resolution of 200 μm3 and FOV of 36.5xa0cm3. Cone beam (CB) CT of the mandible and subjects were acquired. MRI was compared to CBCT and histological sections. Deviations were calculated with intraclass correlation coefficient (ICC) and coefficient of variation (cv).ResultsA high congruence between CBCT, MRI and specimens was demonstrated. Hard and soft tissues including dental pulp, periodontium, gingiva, cancellous bone and mandibular canal contents were adequately displayed with MRI.ConclusionsImaging of select intraoral tissues was achieved using custom MRI protocols with an easily applicable intraoral coil in a clinically acceptable acquisition time. Comparison with CBCT and histological sections helped demonstrate dimensional accuracy of the MR images. The course of the mandibular canal was accurately displayed with CBCT and MRI.Key points• MRI is a clinically available diagnostic tool in dentistry• Intraoral hard and soft tissues can be imaged with a high resolution with MRI• The dimensional accuracy of MRI is comparable to cone beam CT

Sensitivity and specificity of cone beam computed tomography in thin bony structures in maxillofacial surgery – A clinical trial.

INTRODUCTIONnCone-Beam Computed Tomography (CBCT) has become widely used in dentistry and maxillofacial surgery. Accuracy, sensitivity and specificity of thin bony structures below 0.5 mm have been subject of some in vitro studies. This prospective in vivo study investigates the correlation between preoperative CBCT-imaging and intraoperative clinical examination of thin bony structures. We hereby present results from daily clinical routine.nnnMETHODSnA total number of 80 sites in 64 patients has been examined to differentiate between preoperative 3D imaging and clinical measurements on cystic lesions in maxilla and mandible. Different CBCT-devices with a voxel size ranging from 0.08 mm to 0.4 mm were used.nnnRESULTSnOverall-specificity found for detecting thin bony structures of the human jaw is 13.89%, overall sensitivity is 100%, positive predictive value (PPV) is 58.67% and negative predictive value (NPV) is 100%.nnnDISCUSSIONnImage quality is the key to make use of additional information CBCT provides and depends on spatial, temporal and contrast resolution. CBCT does not depict reliably thin bony structures of the jaw, even if high voxel resolution is used.nnnCONCLUSIONnIn selected cases using high resolution protocols should be considered despite affecting the patient with higher doses of radiation.

Is the presence of keratinized mucosa associated with periimplant tissue health? A clinical cross-sectional analysis

BackgroundLong-term data concerning the impact of missing keratinized mucosa (KM) on periimplant tissue health are rare. The importance of KM for implant success remains unclear.MethodsTwo hundred eleven patients with 967 dental implants were analyzed up to 15xa0years after implant placement. Implants were divided into two groups: no keratinized mucosa (NKM) and KM. Evaluated parameters were plaque index (mAPI), bleeding index (mSBI), bleeding on probing (BOP), probing depth (PD), width of KM, and radiographic vertical bone level.ResultsmAPI, mSBI, and BOP were significantly higher for the NKM group. Implants of both groups showed no significant difference in PD and vertical bone level. Of the implants in the posterior regions (nu2009=u2009261), 40.3% (regions 37 to 34, 44 to 47, 27 to 24, 17 to 14) showed NKM, whereas 30.4% of the implants in the anterior regions (regions 13 to 23; regions 33 to 43) presented NKM (nu2009=u200997).ConclusionsResults indicate that the presence of KM has a positive effect on periimplant tissue health, but does not seem to have an influence on the periimplant bone level.

Zoledronate induces bisphosphonate-related osteonecrosis of the jaw in osteopenic sheep

ObjectivesBisphosphonate-related osteonecrosis of the jaw (BP-ONJ) occurs in 1xa0% of patients with medication-induced osteoporosis treated with bisphosphonates. Sheep are an established large animal model for investigating osteoporotic skeletal changes. Zoledronate significantly reduces tissue mineral variability in ovariectomized sheep. The aim of this study was to analyze bone healing after tooth extraction in sheep with induced osteopenia and zoledronate administration.Materials and methodsEight adult ewes were randomly divided into two groups of four animals. All sheep underwent ovariectomy and a low-calcium diet. Dexamethasone was administered weekly for 16xa0weeks. Zoledronate was then given every third week for a further 16xa0weeks in four sheep; these infusions were repeated after extraction of two lower premolars. Four sheep without zoledronate administrations served as controls.ResultsDue to general health conditions, two sheep of the zoledronate group had to be excluded before surgery. The remaining two sheep of this group developed BP-ONJ lesions at the extraction site and various other sites in both jaws. Control group animals showed uneventful wound healing. Histology of the alveolar processes as well as lumbar spine revealed larger portions of old bone and smaller portions of new bone in the zoledronate group.ConclusionsThis animal study showed uneventful wound healing after tooth extraction in osteopenic sheep whereas zoledronate treatment leads to development of BP-ONJ-like lesions.Clinical relevanceAs bisphosphonate administration is a standard treatment for glucocorticoid-induced osteoporosis, this model can be used for further research in pathogenesis and management of bisphosphonate-related adverse events.

Gorham-Stout syndrome of the facial bones: a review of pathogenesis and treatment modalities and report of a case with a rare cutaneous manifestations

Gorham disease is a very rare condition associated with spontaneous destruction and resorption of 1 or more bones anywhere in the body. Many authors have suggested and/or implicated trauma as the initiating factor in the majority of the reported cases. It can affect almost all bones, and a combination of bones has been reported. In the maxillofacial skeleton, the first facial case was reported by Romer in 1928. Until now, only a few cases of Gorham disease affecting the maxillofacial bones, including this case report, have been reported. We present a brief review of the pathogenesis and treatment modalities of the disease and report a very rare clinical picture of the disease affecting a young and otherwise healthy patient with massive osteolysis of the mandibular bone and extensive involvement of the mouth floor and skin of the chin, which to our knowledge, is the only case report with skin manifestation affecting the maxillofacial region. Such skin manifestations play an important role for the diagnosis and add a clue for management of such condition.

Zoledronate induces osteonecrosis of the jaw in sheep

INTRODUCTIONnThe treatment of bisphosphonate-related osteonecrosis of the jaw has become routine in maxillofacial hospitals. However, the etiopathology has not yet been fully understood. The aim of this study was to develop a large animal model for medication-related osteonecrosis of the jaw (MRONJ).nnnMATERIAL AND METHODSnEight Swiss mountain sheep were randomly assigned into two groups. Group I received 0.075 mg/kg zoledronate (ZOL) intravenously every third week for 16 weeks. After 16 weeks, extraction of the first and second lower left premolar was performed. Group II underwent surgery and no ZOL was administered. After surgery, Group I continued to receive ZOL infusions; after 16 weeks, all animals were euthanized. The jaw bones were investigated macroscopically, radiographically (computed tomography) and histologically.nnnRESULTSnOsteonecrosis of the jaw was observed at all extraction sites in all the animals receiving ZOL, and at none of the sites in animals without ZOL. All ZOL-treated animals spontaneously developed exposed bone lesions in the oral cavity at sites where no surgical intervention was performed. CT imaging shows persistent alveolar extraction sockets 16 weeks after surgery in all animals of the ZOL-group, and healed alveolar extraction sockets in non-ZOL-treated animals.nnnCONCLUSIONnSheep treated with ZOL reproducibly demonstrated osteonecrosis of the jaw after tooth extraction, and spontaneous development of exposed bone in the oral cavity at sites where no manipulation was performed. This animal model can be used for further research in the fields of BP-ONJ etiopathology, oral implantology, bone and fracture healing and periodontology.

Clipping of tumour resection margins allows accurate target volume delineation in head and neck cancer adjuvant radiation therapy.

BACKGROUNDnAccurate tumour bed localisation is a key requirement for adjuvant radiotherapy. A new procedure is described for head and neck cancer treatment that improves tumour bed localisation using titanium clips.nnnMATERIALS AND METHODSnFollowing complete local excision of the primary tumour, the tumour bed was marked with titanium clips. Preoperative gross target volume (GTV) and postoperative tumour bed were examined and the distances between the centres of gravity were evaluated.nnnRESULTSn49 patients with squamous cell carcinoma of the oral cavity were prospectively enrolled in this study. All patients underwent tumour resection, neck lymph node dissection and defect reconstruction in one stage. During surgery, 7-49 clips were placed in the resection cavity. Surgical clip insertion was successful in 88% (n=43). Clip identification and tumour bed delineation was successful in all 43 patients. The overall distance between the centres of gravity of the preoperative tumour extension to the tumour bed was 0.9cm. A significant relationship between the preoperative tumour extension and the postoperative tumour bed volume could be demonstrated.nnnCONCLUSIONnWe demonstrate a precise delineation of the former tumour cavity. Improvements in tumour bed delineation allow an increase of accuracy for adjuvant treatment.