【Abstract】 Objective To evaluate the feasibility and effectiveness of reconstruction of mandibular bone defects using three-dimensional skull model and individualized titanium prosthetics from computer assisted design. Methods Between July 2002 and November 2009, 9 patients with mandibular defects accepted restorative operation using individualized bone prosthetics. Among 9 cases, 4 were male and 5 were female, aged 19-55 years. The causes of mandibulectomy were benign lesions in 8 patients and carcinoma of gingival in 1 patient. Mandibular defects exceeded midline in 2 cases, involved condylar in 4 cases, and was limited in one side without involvement of temporo-mandibular joint in 3 cases. The range of bone defects was 9.0 cm × 2.5 cm-17.0 cm × 2.5 cm. The preoperative spiral CT scan was performed and three-diamensional skull model was obtained. Titanium prosthetics of mandibular defects were designed and fabricated through multi-step procedure of reverse engineering and rapid prototyping. Titanium prosthetics were used for one-stage repair of mandibular bone defects, then two-stage implant denture was performed after 6 months. Results The individualized titanium prosthetics were inserted smoothly with one-stage operative time of 10-23 minutes. All the cases achieved incision healing by first intention and the oblique mandibular movement was corrected. They all got satisfactory face, had satisfactory contour and good occlusion. In two-stage operation, no loosening of the implants was observed and the abutments were in good position with corresponding teeth which were designed ideally before operation. All cases got satisfactory results after 1-9 years of follow-up. At last follow-up, X-ray examinations showed no loosening of implants with symmetry contour. Conclusion Computer assisted design and three-dimensional skull model techniques could accomplish the design and manufacture of individualized prosthetic for the repair of mandibular bone defects.
Objective To investigate the method of combining radial forearm free flap and adjacent tissue flap in reconstruction of palatomaxillary defects and its effectiveness. Methods Between March 2005 and May 2010, 17 patients with palatomaxillary defects were treated. There were 11 males and 6 females with an age range of 45-74 years (mean, 62.5 years), including 1 case of benign tumor and 16 cases of malignant tumors (7 cases of squamous cell carcinoma of palate, 1 case of recurring squamous cell carcinoma of palate, 1 case of malignant melanoma of palate, 1 case of adenoid cystic carcinoma of palate, 1 case of malignant melanoma of maxilla, 1 case of ductal carcinoma of maxilla, and 4 cases of squamous cell carcinoma of maxilla). The maxillectomy defect ranged from 7.0 cm × 5.5 cm to 10.0 cm × 7.5 cm. According to Brown’s classification for the maxillectomy defect, there were type II in 15 cases, type III in 2 cases. Palatomaxillary defects were repaired with radial forearm free flap and buccal fat pad in 11 cases, and with radial forearm free flap, buccal fat pad, and mandibular osteomuscular flap pedicled with temporal muscle in 6 cases. The effectiveness was evaluated after operation by observing the vitality of the flap, the functions of speech, swallowing, breath, and the facial appearance. Results All cases were followed up 6-12 months without tumor recurrence. All flaps and skin grafts at donor sites survived. The functions of seech, swallowing, and breath were normal without obvious opening limitation. The facial appearance was satisfactory without obvious maxillofacial deformity. No enophthalmos occurred in patients with orbital floor and infraorbital rim defects. The patients had no oronasal fistula with satisfactory oral and nasal functions. Conclusion According to the type of palatomaxillary defects, it can have good early effectiveness to select combining radial forearm free flap and buccal fat pad or combining radial forearm free flap, buccal fat pad, and mandibular osteomuscular flap for repairing defects.
OBJECTIVE: To establish the animal models of mandibular distraction osteogenesis in rabbits and study its osteogenetic mechanism. METHODS: The right mandibles just anterior to the first molars of 12 rabbits were performed osteotomies, and the mandibles were positioned with distractors. The left mandibles were control group without operation. After 1 week, the distractors were stretched 0.9 mm every day for 10 days progressively. One day, 2, 4, 8 weeks after distraction, the mandibles were studied with gross measurement, X-ray, and histological examination. RESULTS: The right mandible were lengthened 8.3 mm on average without bone nonunion and deformity healing. It was observed that the gaps between the distracted bone edges were first occupied by fibrous tissue. Two weeks after distraction, it was found that the gaps were bridged by callus in X-ray, the new bone and the normal bone could not be differentiated clearly after 8 weeks. In histological sections, there were collagen bundles in early distraction, then those collagen bundles were calcificated and become trabeculaes. No Cartilage was found during distraction. CONCLUSION: It suggests that the rabbit mandible can be lengthened by distraction osteogenesis, and the new bone is formed by intramembranous ossification.
Objective To investigate the mode and influential factor of newbone formation following distraction osteogenesis in mandibular lengthening. Methods Corticotomy was performed on bilateral mandibles in twelve adult male goats. A custommade distractor was used to lengthen the mandible at a rate of 1mm/day for 10 days (total 10 mm elongation). Four goats were sampled respectivelyat 2, 4 and 8 weeks after completion of distraction. The lengthening mandibles were examined by roentgenography and histology. Results Newly formed callus was observed in the distraction gap after mandibular lengthening. The new bone exhibited intramembranous ossification generally, but cartilage islands could be found in the specimen that diastractor loosed. Conclusion The above findings indicate that the mode of new bone formation in mandibular lengthening following distraction osteogenesis appears to be intramembranous ossification and that endochondral ossification takes place in case distractor has loosened.
【Abstract】 Objective To assess the feasibility and clinical outcomes of artificial condylar process in reconstruction of the temporomandibular joint. Methods Between January 2005 and January 2010, the reconstructions of the temporomandibular joints with artificial condylar process were performed in 10 cases (11 sides, including 7 left sides and 4 right sides). There were 7 males and 3 females with an average age of 50 years (range, 40-68 years). Mandibular condyle defects were caused by mandible tumor in 7 patients with a mean disease duration of 15 months (range, 9-24 months) and by bilateral condylar fractures in 3 patients with the disease duration of 2, 3, and 2 days respectively. According to Neff classification, there were type M and A in 1 case, type M and B in 1 case, and type M in one side and subcondylar fracture in the other side in 1 case. Results Incisions in all patients healed by first intention, and no complication occurred. All cases were followed up 1 to 4 years, showed facial symmetry and good occluding relation, and the mouth opening was 22-38 mm (mean, 30 mm). No temporomandibular joint clicking or pain and no recurrence of tumor were observed. Most of the artificial condylar process were in good position except 1 deviated from the correct angle slightly. All the patients could have diet normally. Conclusion The results of temporomandibular joint reconstruction after tumor resection with artificial condylar process are good, but the clinical outcome for intracapsular condylar fracture is expected to be further verified.
Objective To investigate the application of rigid internal fixation in mandibular reconstruction with autogenous bone and to evaluate its efficacy. Methods From January 1994 to May 2004, 98 patients with mandibular defect received mandibular reconstruction with autogenous bone by using rigid internal fixation. Seventy-two cases of benign tumor and 26 cases of malignant tumor were included. Four hundred and ono rigid fixation plates were inserted.The clinical results and X-ray films were analyzed and the healing processes were evaluated. The functional and aesthetic results of the mandibular reconstruction were also evaluated according to Lopez assessment system. Results After a follow-up of 1 to 3 years, 95 patients（96.9%）achieved successful effect. The forms and function of the mandibleswere resumed. Eightyone （82.7%）patients were satisfied with the results ofoperations. Thirteen patients（13.3%） achieved acceptable results. Four patients (4.1%) were dissatisfied with the results of operations. Conclusion The rigid internal fixation is conductive to healing and remodeling ofthe transplant bone in mandibular reconstruction.
Objective To investigate the clinical effect ofthe pectoralis major myocutaneous flap and Ti-plate system in repairing mandibular defects caused by resection of oral carcinoma.Methods From November 2001 to February 2003, 32patients with mandibular defect caused by resection of oral carcinoma were treated. Combined radical neck dissection with resection of gingival and mandible was performed on 11 patients with carcinoma of the lower gingival, combined radical neck dissection with glossectomy and mandibulectory on 13 patients with carcinoma of tongue, combined radical neck dissection with resection of floor of mouthand mandible on 4 patients with carcinoma of floor of mouth, and combined radical neck dissection with resection of cheek and mandible on 4 patients with carcinoma of buccal mucosa, respectively. The defects of mandible were associated with soft-tissue component, the sizes of defect ranged from 5.5 cm×7.6 cm to 8.2 cm×10.5 cm. The defects were reconstructed with 6 cm×7 cm to 9 cm×10 cm pectoralis major myocutaneous flaps and Tiplate system. The effect was studied retrospectively. Results Thirty-two cases were followed for 219 months; 29 cases offlaps survived and 3 cases of flaps partly necrosed (10% or less of the skin paddle). The appearance of face was satisfactory in 27 patients, and slight deformity of face was observed in 5 patients. The occluding relation and masticatory function were recovered well. Opening mouth extents ranged from 2.7 cm to 3.4 cm. No temporomandibular arthrosis relating to operation was found in all cases. Conclusion A combination of thhe pectoralis major myocut aneous flap and Ti-plate system is an ideal method for reconstruction of mandible defects associated with soft-tissue component after radical operation of oral carcinoma.
Objective To build up a new contour and functional reconstruction technique of mandibular defects with rapid prototyping and reverse engineering technique. Methods From April 2002 to August 2004, 4 cases of mandibular defects due to resection of large mandible lesion were treated. Of 4 patients, there were 3 females and 1 male, with an age range of 21-42 years, which underwent secondary operation and presented a deviation as mandibular movement. The openingmouth extent was 1.8-2.5 cm(2.2 cm on average). The data of defects area were renewed withMimics and Geomagic Studio software; and the titanium reconstructive frame was designed and manufactured with rapid prototyping technigue. Defect were reconstructed by using CT digital data of patients. Results The CT data could be used by image software directly. The implant design could be completed by computer-aimed design(CAD)/computer-aided manufacture(CAM). The resin model and titanium frame were manufactured accurately by RP technique. Four patients achieved one stage healing. After a follow-up of 3 months to 2 years, largemandibular defect was reconstructed satisfactorily and the opening-mouth extent was 3.03.4 cm(3.2 cm on average). The occluding relation was normal. The implant denture was put on and the mastication function was good in 1 case. Conclusion Individual design and repair of large mandibular defect with CAD/CAM techniques is worth extending application clinically. It is a simple and accurate method.
ObjectiveTo investigate the clinical outcomes of resection of mandibular benign tumors and primary reconstruction with autogenous bone graft via an intraoral approach. MethodsFifteen patients with mandibular benign tumors were treated between January 2009 and September 2012. There were 7 males and 8 females, aged from 18 to 45 years (mean, 30 years). The pathological diagnosis identified 11 cases of ameloblastoma, 3 cases of odontogenic keratocyst, and 1 case of odontogenic myxoma. According to the Urken's CRBS (Condyle, Ramus, Body, Symphysis) classification criteria based on the location of the mandibular defect, there were 3 cases of body type (B type), 3 cases of ramus type (R type), and 9 cases of body and ramus type (BR type). The surgeries were performed via an intraoral approach, except 1 patient with the lesion at the level of sigmoid notch via an auxiliary preauricular incision. To fix the bone grafts to the dissected mandibular defects, reconstructive titanium plates were used, either indirectly according to the computer aided design/computer aided manufacturing mandibular models before surgery (9 patients) or directly according to the exposed mandibles during surgery (6 patients). The patients received benign mandibular tumor resection and primary autogenous bone graft reconstruction with free iliac bones (11 cases) or vascularized fibular flaps (4 cases). The mandibular inferior alveolar nerves were preserved in 6 cases. ResultsPrimary healing of incision was obtained in 14 patients, while secondary healing in 1 patient suffering from bone graft infection. All the patients were followed up 1-4 years (mean, 2.5 years). At last follow-up, no patients showed facial nerve damage; occlusion of remaining teeth was similar to preoperative conditions; the chewing function was satisfactory; mouth opening was 30-35 mm (mean, 33 mm); and swallowing and speaking functions were normal. Only slight extraoral scars caused by the auxiliary incision and the transbuccal appliances were observed, and all the patients were satisfied with the facial appearance. Lower lip numbness was relived in patients with preserved inferior alveolar nerves. There was no tumor recurrence during follow-up period. ConclusionThe intraoral approach is a feasible and proper approach for resection of benign mandibular tumors and primary reconstruction with autogenous bone grafts, with the advantages of inconspicuous facial scars, minimum damage to the facial nerve, and expectable aesthetic appearance.
Objective To systematically review the efficacy of poly-L-lactide (PLLA) material treatment versus titanium plates treatment for mandibular fractures. Methods We searched the Cochrane Library, PubMed, Embase, Chinese Journal Full-text Database, VIP Database, and Wanfang Database to collect literatures about randomized or non-randomized controlled trials using PLLA treatment (the trial group) versus titanium plates treatment (the control group) for mandibular fractures in the last ten years (from January 2007 to March 2017). The quality evaluation and data extraction were carried out by 2 reviewers independently and analyzed by Review Manager 5.3 software. Results A total of 8 literatures including 453 patients with mandibular fractures were included in this Meta-analysis. There was no significant difference in total complications between the two groups [odds ratio (OR)=0.98, 95% confidence interval (CI) (0.55, 1.75), P=0.95], including dislocation healing [OR= 0.96, 95%CI (0.46, 2.01), P=0.90], occlusal disturbance [OR=1.53, 95%CI (0.61, 3.87), P=0.37], infection [OR=0.63, 95%CI (0.23, 1.74), P=0.37], and secondary operation [OR=0.46, 95%CI (0.17, 1.27), P=0.14]. Conclusion There is no significant difference between PLLA and titanium plate in the treatment of mandibular fractures.