Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Mandibular Prosthesis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources
PubMed2005

A modified repositioning system for segmental resection of the mandible.

Mandibular reconstruction is required after segmental resection of the mandible. Several techniques have been proposed but have several drawbacks. A modified system (based on Leibinger's titanium-positioning system) that can reposition the residual mandible easily and accurately without interfering with the reconstructive procedure was developed. This system has been used successfully in more than 10 patients, with no complications.

Acrylic Resins↗
PubMed2006

Reconstruction of large defects postmandibulectomy for oral cancer using plates and myocutaneous flaps: a long-term follow-up.

A series of 28 consecutive cases of mandibular reconstruction by means of reconstructive plates and myocutaneous flaps were reviewed. In all cases mandibular resection was indicated for treatment of squamous cell carcinoma of the oral cavity: 25 pelviglossomandibulectomies (resulting in large defects from the angle of the mandible), 2 Commando operations (resulting in lateral defects) and 1 anterior sectional mandibulectomy (resulting in an anterior defect). Tumour stages were T1-T2 (4 cases) and T3-T4 (24 cases). Success was defined as plate maintenance 6 months' postoperatively/postradiotherapy. The overall success rate was 32.2%. Lateral-centre-lateral (L-C-L) defects had 32% success, L (lateral) defects had 50% success and in the single case of a C (centre) defect, the plate was not maintained. Stainless steel reconstruction plates showed a similar success rate as titanium plates (30% versus 34%). In cases not submitted to radiotherapy there were more maintained plates than in cases that received radiotherapy (45.5% versus 23.6%). Reconstruction plates are not effective in bridging large defects of the resected mandible. Only in selected cases that are not eligible for microvascular free flaps should plates and myocutaneous flaps be considered as an option for mandibular reconstruction.

Adolescent↗
PubMed2006

Reconstruction of the mandible after ablative surgery for the treatment of aggressive, benign odontogenic tumours in Tanzania: a preliminary study.

This study presents results on 11 patients suffering from ameloblastoma who had ablative surgery followed by reconstruction of the mandible in a single operative procedure in Tanzania. The procedure included the use of autogenous particulate bone from the anterior or posterior iliac crest. In 6 of the patients, the tumour was removed from the cortical scaffold, which was then irradiated with 50 Gy. Perforations were made on the scaffold and it was then placed back to fit the defect and was held in place by custom-made titanium plates, fixed on both ends with screws. The particulate bone chips were mixed with autogenous platelet rich plasma (PRP) and Tissue Col. In 5 of the patients, the cortical scaffold was not used but rather a mixture of bone and PRP was packed into the defect under the titanium plates. Four patients had some complications varying from fracture of the scaffolds to infection. None from the group reconstructed without scaffolds suffered any complications. A quality of life (QOL) assessment of the 7 successful cases showed that these patients were satisfied and had a good QOL. These results imply that this immediate means of reconstruction is feasible and thus, offers a big advantage to the patients.

Adolescent↗
PubMed2006

Osteopetrosis complicated by osteomyelitis of the mandible: a case report including characterization of the osteopetrotic bone.

A case of a 53-year-old Japanese man with osteopetrosis complicated by osteomyelitis of the mandible is presented. The patient experienced frequent exacerbations and remissions of osteomyelitis of the mandible, despite undergoing several surgical debridements and sequesterectomies with appropriate antimicrobial therapy, for 3 years. Finally, the patient underwent mandibular segmental resection followed by reconstruction with a titanium reconstruction plate. Fifty-one months after surgery there is no evidence of recurrent osteomyelitis of the mandible, suggesting that a more radical surgical approach is preferable for patients with severe complications resulting from osteopetrosis. Also presented here are the histopathological and biochemical features of the osteopetrotic bone. The osteopetrotic cortical bone was morbidly sclerotic with compact and irregular laminations. Degradation of osteocytes in the osteopetrotic bone was due to hypoxia and lack of nutrition resulting from osteosclerosis. There were no significant differences between osteopetrotic and normal bone according to X-ray diffraction, Fourier transform infrared spectroscopy, collagen content or mineral content. Micro-Vickers hardness measurements showed that osteopetrotic bone was significantly harder than normal bone, and the standard deviation of hardness was greater in osteopetrotic bone. Such a loss of integrity in osteopetrotic bone is considered to be a primary reason for the greater risk of a variety of complications such as pathological fracture and refractory osteomyelitis.

Bone Plates↗
PubMed2006

Adaquate fixation of plates for stability during mandibular reconstruction.

PURPOSE: To determine the most appropriate plate fixation for dispersing the stress around screws in mandibular reconstruction. MATERIAL AND METHODS: Forty-eight three-dimensional reconstructed mandibular models with Central (C) or right Lateral (L) defects were created and divided into three groups, fixed with: (1) two screws on each side, (2) three screws on the left side with the third (middle one) located distally, or (3) three screws on the left side with the third (middle one) located proximally. A 300N vertical load was applied to the left molar region. The maximum stress was calculated using a finite element method and statistically evaluated. RESULTS: Stress was concentrated around the screw at the distal end of the mandibular halves on the loaded side ('crucial screw'). For the C defect, stress concentrated around the 'crucial screw' was greater when there were only two screws for fixation (20.55MPa) than when there were three screws (16.17MPa; p=0.022). No significant difference was found between the two groups with three screws for fixation. For the L defect on the other hand, stress on the 'crucial screw' was relatively greater when there were three screws for fixation (18.9MPa) than when there were only two screws for (12.83MPa; p=0.051). No significant difference was found between the two groups with three screws for fixation. As for the reconstruction plate, the stresses on the plates were not different among the various screw groups for fixation nor among the C and L defects. CONCLUSION: This paradoxical result is explained by plate bowing. Thus in large defects screw positions should take into consideration the potential for plate bowing.

Bite Force↗
PubMed2006

Analysis of mechanical stress in reconstruction plates for bridging mandibular angle defects.

INTRODUCTION: The objective of the present study was to evaluate the mechanical stress in reconstruction plates and the screw-plate-bone interface used in bridging a mandibular angle defect by means of the finite element method (FEM). The influence of plate geometry as well as the configuration and the diameter of the screws on the mechanical stress distribution was to be determined at the same time and was used as the basis for developing suggestions to optimize the design of the reconstruction plates. MATERIAL: Based on the geometrical data of a human mandible, an angle defect bridged by a titanium reconstruction plate was generated and exposed to chewing force. First a reconstruction plate was tightly fixed with M2.7 titanium screws. Then, plate design, screw configuration and screw diameter were varied. The mechanical stress was calculated according to von Mises stress hypothesis. RESULTS: In the standard reconstruction plate, the result of the finite element analysis revealed stress resulting from the simulated functional loadings which far exceeded the strengths of the components. Possible clinical consequences could be a fatigue fracture of the plate itself, gradual loosening of the osteosynthesis screws and loss of bone. The stress can be reduced to less than half by increasing the diameter of the screw threads 1.5 fold. CONCLUSION: Maximizing the interface between bone and reconstruction plate had a favourable effect. As a consequence of the large interface and a triangular or square configuration of the screws, the stresses could be substantially reduced, the plate could be made thinner and thus better adapted to the mandible. As a preliminary result, the newly designed reconstruction plate could be thinned in areas subject to less mechanical stress.

Bite Force↗
PubMed2004

Comparative study of locking plates in mandibular reconstruction after ablative tumor surgery: THORP versus UniLOCK system.

PURPOSE: This retrospective study compared 2 types of rigid locking plates (THORP and UniLOCK; Stratec Medical, Oberdorf, Switzerland) in 107 patients undergoing reconstruction for bridging mandibular defects following ablative tumor surgery. PATIENTS AND METHODS: From January 1993 to December 2000, 107 patients were reconstructed following ablative tumor surgery with 57 THORP plates and 50 UniLOCK plates. Study follow-up ranged from 18 to 87 months (average, 32 months). Complications were categorized into delayed wound healing, infection, plate exposure, and plate fracture, taking into account the type and timing of reconstruction. RESULTS: Overall type and number of complications show no statistically significant differences between THORP and UniLOCK groups. Infection was the most frequent type of complication (THORP, 30; UniLOCK, 32). Others included delayed wound healing (THORP, 13; UniLOCK, 12), plate exposure (THORP, 8; UniLOCK, 7), and plate fracture (THORP, 5; UniLOCK, 1). Plates were removed in 22 THORP and 11 UniLOCK plates. The most frequent reason for plate removal in both groups was infection. Other reasons for plate removal include tumor recurrence, plate fracture, plate exposure, or a combination of reasons. CONCLUSIONS: THORP and UniLOCK plates do not present statistically significant differences in the parameters studied. Nevertheless, the UniLOCK group had slightly better results. Considering that the THORP system is much bulkier and its screws bigger, our results lead to the conclusion that bridging osteosynthesis with a 2.4 UniLOCK system is adequate for plate reconstruction of mandibular defects.

Adult↗
PubMed2005

Removal of miniplates in maxillofacial surgery: a follow-up study.

PURPOSE: We sought to follow-up a cohort of patients who had miniplates (plates) inserted in the oral and maxillofacial region during a 13-month period over 4 years to study the incidence and factors associated with plate removal. PATIENTS AND METHODS: One hundred fifty-three patients had plates inserted in the oral and maxillofacial region in the Department of Oral & Maxillofacial Surgery, University Hospital Birmingham, UK, between November 1, 1998, and November 30, 1999. All 153 patients' records were revisited on or after October 31, 2002, giving a minimum follow-up of 3 years and a maximum of 4 years. RESULTS: During a period of 13 months (November 1, 1998 through November 30, 1999), 308 plates were inserted into 153 patients. A total of 32 plates were removed from 21 patients by October 31, 2002, (10.4%) over 4 years; 27 plates were removed from 16 patients for purely plate-related symptoms, with infection being the most common cause accounting for 16 plates (50%) in 9 patients. Symptoms necessitating plate removal occurred within 52 weeks after insertion in 16 patients, accounting for 23 of the plates removed (72%). The age of the patient at plate insertion may have some influence on plate removal but this was not significant. Seniority of the operator did not affect plate removal. CONCLUSION: Our experience with the removal of miniplates compares with previously published reports. Longitudinal follow-up at 4 years indicates that plate-related problems leading to removal are likely to occur in the first year after insertion.

Adolescent↗
PubMed2006

Failure strength of 2.0 locking versus 2.0 conventional Synthes mandibular plates: A laboratory model.

PURPOSE: This laboratory study compared the performance of locking versus nonlocking Synthes (Synthes, Paoli, PA) 2-mm mandibular fixation plates. The purpose of the study was to determine if there are physical or mechanical properties to support the use of one rigid fixation device over the other. MATERIALS AND METHODS: A bovine rib model was selected for this study because they closely approximate characteristics of the human mandible. Two experimental groups composed of 10 locking and 10 nonlocking 2-mm plates were secured to randomly selected osteotomized bovine ribs using 10-mm monocortical screws. The specimens were loaded using a 4-point bending system to the point of failure using a MTS model 309.00 servo-hydraulic testing system (MTS Systems Corp, Eden Prairie, MN) with a custom fabricated fixator. The data was obtained with TestStar 2 version 4.0 and TestWare Sx 4.0 software (MTS Systems Corp), and analyzed to determine if there was any difference in performance between the 2 mandibular plate designs. RESULTS: Overall, there were no statistically significant differences between the locking and conventional 2-mm mandibular plate. Of the 20 samples tested, 1 (nonlocking) had a unique early screw failure (pullout) inconsistent with any other samples and was not analyzed. Of the remaining 19 samples, 17 produced a yield failure, bend, or stretch rather than a plate fracture. Both of the plate fractures occurred in the nonlocking plates. Although the data suggested that this mode of failure was more common in nonlocking plates, the difference between both groups in the mode of failure did not achieve statistical significance (chi2 = 2.0, P = .16). Thus, yield was the predominant mode of failure for both types of devices. The force at which each device failed was also similar in both groups. The force of failure for the nonlocking plates was 559.9 N (SD = 247.9), whereas the locking plate failure strength was 637.8 N (SD = 276.3; t (17) = 0.6, P = .53). The results indicated that there was no suggestion that one plate might be stronger than the other. CONCLUSIONS: In this laboratory model, no significant differences were found between the 2 types of mandibular plates. Although studies have shown the locking system to be more rigid, this study suggested that the type and degree of failure are more likely related to bone quality and surgical technique when using the 2-mm mandibular plate. Additional prospective studies are needed to correlate these results in patient models.

Animals↗
PubMed2005

Long-term outcome and factors influencing bridging plates for mandibular reconstruction.

Vascularized bone grafts have become the preferred method of mandibular reconstruction. However, the technique is considered to increase both the operating time and blood loss, which might be associated with an increased morbidity and mortality. We conducted a retrospective analysis of 100 consecutive patients who underwent immediate bridging plate reconstruction. The median follow-up duration was 70 months. The 5-year overall survival rate was 69.9%. Cox multivariate analysis revealed that red blood cell transfusion was an independent prognostic factor for the overall survival. The plate survival with no complications was 62.2% at 5 years. Anterolateral defects and preoperative radiotherapy emerged as an independent adverse factor for plate survival. The use of bridging plates is an option for lateral mandibular reconstruction with no preoperative irradiation to avoid the risk from blood transfusion.

Adolescent↗
PubMed2006

Bridging mandibular continuity defects with miniplates: an experimental study.

Various miniplate fixation techniques were studied in dogs to determine whether the use of miniplate fixation provides sufficient stability in mandibular continuity defects. Continuity resections measuring 15 mm were made on the mandibles of 16 dogs and were bridged using 4 miniplate fixation techniques, each replicated 4 times. All dogs were placed on a normal diet throughout the postoperative period. Clinical and radiological examinations were carried out 6 weeks later. We found that the group with both double miniplates and bicortical screws was stable, whereas the groups utilizing either a single miniplate or monocortical screws were not. The results of this study indicate that using a combination of double miniplates and bicortical screws to bridge defects after mandibular resection produces stable and predictable results.

Animals↗
PubMed1995

Long-term evaluation of patients undergoing immediate mandibular reconstruction.

BACKGROUND: Immediate reconstruction following segmental mandibulectomy is an accepted surgical technique. The benefits and patient selection criteria need to be established. PATIENTS AND METHODS: Forty-seven patients who underwent immediate reconstruction of the mandible were followed for up to 14 years. Survival, complication rates, and functional results were analyzed. RESULTS: Median survival was 39 months and actuarial 5-year survival was 40%. Two patients died in the postoperative period, and 9 suffered major reconstruction-related complications. The majority of these complications were related to the use of reconstruction plates, and occurred when the mandibular defect included the arch or when the plates were covered by pectoralis flaps. Half of the patients interviewed were able to eat a regular diet. CONCLUSIONS: Mandibular reconstruction can be performed safely and expeditiously in nearly all patients undergoing segmental mandibulectomy. Functional results and long-term survival will be acceptable in many cases.

Actuarial Analysis↗