Mandibular Discontinuity Research Articles

Prosthodontic Rehabilitation of Speech, Mastication & Functional Occlusion in Maxillary Insufficiency & Mandibular Discontinuity Defects: A Review

Prosthodontic rehabilitation of patients undergoing ablative cancer procedures involves significant challenges and technicalities in the construction of a prosthesis like repeated prosthetic adjustments or remakes, and ultimately improving quality of life. Mandibular resection causes the mandible to deviate towards the defect, which causes loss of occlusion on the non-resected side, altered mandibular movements, cosmetic deformity, difficulty in swallowing, and impaired speech and articulation. Restoring speech, deglutition, mastication, and respiration in individuals who have undergone maxillary resection involving the maxillae, hard and soft palates, and paranasal sinuses is extremely difficult. It may not be feasible to surgically reconstruct in each case. In conjunction with physical therapy, prosthetic rehabilitation assists such patients in regaining form and function and improving their quality of life. It can be achieved by using obturators and mandibular guidance prosthesis, which could efficiently retrain the maxilla and mandible following surgical procedures to achieve a functional occlusal relation, enabling early progression leading to a permanent restoration that functions almost perfectly. This review's objective is to highlight the various rehabilitative prosthesis that can be used to correct maxillary insufficiency and mandibular discontinuity defects following tumour resections using the available information.

Comparison outcome of open and close reduction treatments for parasymphysis mandibular fractures

Background: Mandibular fracture is a condition of mandibular discontinuity. The treatment aims to reconstruct the appropriate anatomical position. Reduction is the process of repositioning fracture fragments to their original anatomical positions, which can be done by open and closed techniques. Open reduction is more invasive, and the possibility of nerve or blood vessel injury and infection postoperatively is greater. Closed reduction also has postoperative complications such as muscle atrophy, periodontal tissue and mucosa damage, speech disorders, and nutritional disorders. In the final determination of the treatment plan, the advantages, disadvantages, and risks of each treatment and the risk of complications should be sufficiently discussed with patients and the patient’s guardians. Purpose: This case aims to compare the outcome of open reduction and internal fixation (ORIF) with closed reduction treatment in the management of mandibular parasymphysis fractures. Cases: Two case studies of mandibular parasymphysis fractures. Clinically, each patient had mandibular displacement and occlusion disturbance before treatment. Case Management: The treatment plan is considered by the patient’s age and fracture type. One patient received ORIF, and the other received close reduction treatment with gradual repositioning. Malocclusion after treatment was absent in both cases. Conclusion: Open reduction is recommended for displaced parasymphysis fractures. In cases where the open reduction technique cannot be performed, the closed technique can be an alternative, especially on non-displaced or minimally displaced parasymphysis fractures.

An Innovative Method for Fabricating a Closed Hollow Cast Partial Denture for a Patient with Mandibular Discontinuity Defect: A Case Report

An Innovative Method for Fabricating a Closed Hollow Cast Partial Denture for a Patient with Mandibular Discontinuity Defect: A Case Report

Definitive guiding flange prosthesis for management of hemimandibulectomy: A case report

Management of segmental mandibulectomy defects present a major challenge to the rehabilitation team. Mandibular discontinuity obliterates the equilibrium and mandibular function’s symmetry, which leads to altered mandibular movements, facial disFigurement, incomprehensible swallowing, impaired speech and deviation of the remaining fragment towards the surgical side. While opening the mouth, this deviation intensifies, leading to the opening and closing in the angular pathway. A definitive mandibular guiding flange prosthesis on the resected side can be used productively to stabilize the occlusion and correct the deviation. A new prospective for treating segmental mandibulectomy patients by using only one device both for Physiotherapy and Mastication. Keywords: flange prosthesis; mandibular defects; mandibular resection; hemimandibulectomy.

Patient-specific alloplastic endoprosthesis for reconstruction of the mandible following segmental resection: A case series

Reconstruction of mandibular discontinuity defects remains a challenge for maxillofacial surgeons. Despite vascularized free flaps representing the current gold standard for managing such defects, the search continues for other less morbid yet predictable interventions. This study aimed at reviving the idea of alloplastic mandibular endoprosthesis as a treatment modality for reconstruction of segmental mandibular defects following eradication of benign tumors.To reconstruct their segmental mandibular defects, this case series compiled seven patients who received patient-specific titanium implant (PSI) with osseointegrated components and were designed to receive a restoration for dental rehabilitation. The recruited patient population was followed-up for a period of 3–5 years. Three of the seven PSIs failed due to extensive intraoral mucosal dehiscence or persistent extraoral fistulae. Patients with the 4 surviving PSIs enjoyed good results in terms of occlusion, masticatory function, mouth opening as well as pleasing facial esthetics.The described technique represents a viable less morbid alternative to the standard bone grafting techniques for mandibular reconstruction in carefully selected patients. Further studies are needed to modify the PSI design and surface treatment for better outcomes.

PROSTHETIC REHABILITATION OF DENTULOUS HEMIMANDIBULECTOMY PATIENT - A CLINICAL CASE REPORT

The deformity associated with maxillofacial defects causes more of a psychological imbalance than the actual structural and functional loss. Mandible is the only bone that supports the lower face and aids in performing oral functions. Maxillofacial defects that interrupt the continuity of the mandible results in mandibular deviation and rotation which are evident esthetically as well as occlusally. The prime aims of prosthetic rehabilitation are to restore the patient with improved esthetics and acceptable occlusion. These aims are related to the extent of the mandibular resection, the amount of soft tissue loss, and presence or absence of natural teeth. Mandibular discontinuity defects that are immediately restored with grafts have better prognosis as the continuity of mandible is retained. Maxillofacial prosthesis that can camouflage these defects to restore the facial symmetry, normal appearance and an acceptable occlusion, can not only boost the patient’s morale and assist in bringing them back to the society but also aid in performing their functions more efficiently . This clinical case report describes the prosthetic rehabilitation with a cast partial denture for a patient who underwent a hemimandibulectomy and reconstruction with bone (rib) graft.
 Key words: Hemimandibulectomy, Prosthetic rehabilitation, Amoeloblastoma, Cast Partial denture.

Mandibular Reconstruction With a Deep Circumflex Iliac Artery Flap Using Computer-Assisted and Intraoral Anastomosis Techniques

This study aimed to evaluate intraoral anastomosis of a deep circumflex iliac artery (DCIA) flap in combination with computer-assisted techniques for mandibular reconstruction. Between December 2015 and March 2018, 4 patients with mandibular discontinuity defects caused by ablative tumor surgery were included in the study. Mandibular reconstruction was performed with a DCIA flap using computer-assisted and intraoral anastomosis techniques. A computer-aided design-computer-aided manufacturing cutting guide, a reconstruction stereomodel, and a prebent reconstruction plate were used for mandibular reconstruction in each patient.Anastomosis was performed on the facial artery and vein using the deep circumflex iliac vessels through an intraoral approach. The resulting error-grade color map was used to evaluate repeatability between the preoperative design and postoperative results. Mandibular reconstruction with a DCIA flap using computer-assisted and intraoral anastomosis techniques was successful in all 4 patients. All flaps survived with no severe complications. Satisfactory cosmetic outcomes and occlusion with sufficient bone height for implants were achieved postoperatively. Repeatability between the virtual plan and postoperative result was 81.1%±8.2% within 1mm, 85.8%±8.1% within 2mm, and 89.6%±6.7% within 3mm. The use of intraoral anastomosis and computer-assisted techniques with DCIA flaps for mandibular reconstruction without additional facial scarring is feasible and advantageous. However, the findings should be interpreted cautiously owing to the relatively short follow-up time and limited number of patients involved in this study.

Clinical Study of Reconstruction Plates Used in the Surgery for Mandibular Discontinuity Defect.

Postresective mandibular reconstruction is common in cases of oral and mandibular tumors. However, complications such as plate fracture and/or plate exposure can occur. The purpose of this study was to analyze complications and survival of reconstructive plates used to correct mandibular defects caused by oral cancer. Clinical and radiological data from 34 patients were analyzed. Only discontinuous mandibular defect cases were included in this study. All cases were classified using the Hashikawa's CAT and Eichner's classification methods. Then, we determined whether these classifications and clinical treatment methods were significantly related to complications. Complications after mandibular reconstruction occurred in 10 of 34 patients, specifically, two plate fractures, one screw fracture, and seven plate exposures occurred. The plate fractures occurred 5 and 6 months after operation, and the screw fracture occurred 39 months after operation. Using the Hashikawa's CAT classification, the two cases of plate fracture were one of AT type and the other of T type, and the screw fracture was AT type. Using Eichner's classification, all three cases of plate and screw fractures were B2 type. We suggest that plate and screw fractures were caused by the type of mandibular defect and bite force.

Man as a living bioreactor: Long-term histological aspects of a mandibular replacement engineered in the patient’s own body

In 2016, we reported the world’s first reconstruction of a mandibular discontinuity defect using a custom-made bone transplant that had been prefabricated in the gastrocolic omentum using tissue engineering strategies. However, the tissue of an engineered human neomandible has not been evaluated histologically until now. The current study assessed the long-term histological characteristics of biopsies of the neomandible 9months after transplantation. Histological analysis showed an increased amount of vital mineralized bone tissue after 10months, in comparison to biopsies obtained earlier. The engineered bone covered the surface of the bone substitute material but also grew out typical structures of cancellous bone tissue without a core of BioOss. The amount of induced bone tissue was 32% in the biopsy. In addition, the soft tissue showed an alignment of the connective tissue fibres parallel to the trabecular bone. Increasing time and mechanical forces at the mandible led to an increased amount of mineralized tissue and remodelling of the connective tissue fibres after transplantation. Further research should focus on developing advanced scaffold materials, as the outer titanium mesh cage leads to complications.

ASSESSMENT OF STEREOLITHOGRAPHIC MODELING TECHNOLOGY VERSUS CONVENTIONAL RECONSTRUCTIVE PLATE IN PATIENTS WITH MANDIBULAR DISCONTINUITY DEFECTS

Introduction : One of the goals of mandibular reconstruction after tumor resection is to return to premorbid form and function. Both stereolithography (SLG) and a conventional reconstructive (CR) plates with bone replacement are a valuable for reconstruction following resection of tumors.Purpose: The aim of this study was to compare the outcome of (SLG) modeling technology versus (CR) plate in cases of tumor resection. Materials and Methods: Patients eligible for inclusion in this study had unilateral mandibular discontinuity defects. Patients were randomly divided into 2 groups. Each group comprised 10 patients. In group I (study group), (SLG) modeling technology plates were used, while group II (control group) used (CR) plates. The lesions were resected, and their sites were reconstructed using last mentioned plates, with autogenous bone graft in a second stage. The need for intraoperative plate readjustment, plate placement time and operation time were reviewed. Results: Twenty patients were enrolled in this study. In group I, plates were placed without intraoperative handling. All plates in group II required readjustment. Average operating times were 3.200 ± 0.258 hours in group I and 4.325 ±0.290 hours in group II (P = .000). Mean times for plate placement were 22.900 ± 2.234 minutes and 32.900 ± 2.234 in groups I and II, respectively. The difference resulted in an average time gain of 10 minutes.Conclusion: (SLG) modeling technology is superior in reflecting the bone anatomy than (CR) plate, thus the plate prebending using SLG, eliminating intraoperative plate readjustment and providing better plate adaptation with better contour. It decreases operating time.

Treatment of a mandibular discontinuity defect by using a fibula free flap and an implant-supported fixed complete denture fabricated with a PEKK framework: A clinical report

This clinical report describes the rehabilitation of a patient with a history of mandibulectomy that involved the use of a fibula free flap and an implant-supported fixed complete denture. A recently introduced material, polyetherketoneketone (PEKK), was used as the framework material for the prosthesis, and the treatment produced favorable esthetic and functional results.

THE USE OF TITANIUM MESH COATED WITH HYDROXYAPATITE NANOCRYSTALS IN MANDIBULAR FRACTURE (EXPERIMENTAL STUDY)

INTRODUCTION: Comminuted fractures of the mandible are an important traumatism, in which the mandibular bone is splintered or crushed. Treatment of these types of fractures had always been a challenge to surgeons, considering both the severity of the trauma and the presence of discontinuity defects which require replacement and augmentation in order to treat the bone loss. Titanium mesh was proved to be particularly useful for reconstruction of mandibular discontinuity defects also it can be used as a scaffold for bone grafts. Electrophoretic deposition (EPD) is a coating technique used to increase the osseointegration and increases bone regeneration. OBJECTIVES: To histologically evaluate the effect of titanium mesh coated with hydroxyapatite nanocrystals using electrophoretic deposition on bone osseointegration and healing following comminuted mandibular fractures. MATERIALS AND METHODS: A controlled induced comminuted fracture on the inferior border of the mandible extending from the 2nd premolar to the 2nd molar was performed on 12 mongrel dogs. Six dogs were treated using titanium mesh coated with hydroxyapatite nanocrystals (study group) and the other six using uncoated titanium mesh (control group). The dogs were sacrificed at 2, 4 and 6 weeks and the specimens were dissected to be histologically and radiographically evaluated for new bone formation. RESULTS: The histological outcome showed superior bone healing in the bony defects in the resembling comminuted fracture in the study group than the control group. CONCLUSIONS: The nano-hydroxyapatite coated titanium mesh is a suitable method for reconstruction of comminuted fractures with bony defects

Segmental Mirroring: Does It Eliminate the Need for Intraoperative Readjustment of the Virtually Pre-Bent Reconstruction Plates and Is It Economically Valuable?

The aim of this study was to compare segmental mirroring with mirroring of the entire unaffected side to determine which method obviates intraoperative readjustment of virtually planned pre-bent plates and to evaluate the effect on costs. Patients eligible for inclusion in this prospective study had unilateral mandibular discontinuity defects. Patients were randomly divided into 2 groups. In group I, models were constructed by mirroring the entire unaffected side of the mandible at the midsagittal plane. In group II, only the resected segments were cut and replaced by the corresponding mirrored healthy segments. The lesions were resected, and their sites were reconstructed using pre-bent reconstruction plates. The need for intraoperative plate readjustment, plate placement time, operation time, and operation costs were reviewed. Fifty patients were enrolled in this study. All but 5 plates in group I required readjustment. In group II, plates were placed without intraoperative handling. Average operating times were 4.20 ± 0.56 hours in group I and 3.186 ± 0.28 hours in group II (P = .00002). Mean times for plate placement were 33.36 ± 8.20 and 21.88 ± 5.73 minutes in groups I and II, respectively. The difference resulted in an average time gain of 11.48 minutes. Average personal costs per minute were US$740.77 for group I and US$560.87 for group II. The difference resulted in an average saving of approximately US$179.90. Segmental mirroring is superior in reflecting the bone anatomy in 3-dimensional models, thus eliminating intraoperative plate readjustment and providing better plate adaptation with better contour. It decreases operating time and costs and thus can be recommended for lesions that do not cross the midline.

Immediate loaded implant-supported prosthesis after mandibular reconstruction with free iliac crest bone graft

The head and neck are commonly affected in gunshot injuries and this can cause functional and esthetic defects in the maxillofacial region. Mandibular discontinuity is an important esthetic and functional problem and its reconstruction represents a huge challenge. The opening, closing, lateral and protrusive movements of the mouth are diminished and malocclusion can occur. The purpose is to report a clinical case of a 44 years man who had an immediate loaded implant-supported prosthesis after six months of mandibular reconstruction with free iliac bone grafting of a greatmandibular defect caused by gun shot. Autogenous bone grafting is the most predictable treatment from the available reconstruction options for mandibular bone defects. Reconstructed patients can achieve good results with dental implants and implant-supported prostheses with immediate loading. This treatment can promote better masticatory function, improving the nutrition capacity, facial symmetry, muscular equilibrium, better diction and quality of life.

Reconstruction of the segmental mandibular defect using a retroauricular or modified face-lift incision with an intraoral approach in head and neck cancer

Conclusions: This is the first report of mandibular reconstruction using the retroauricular (RA) or the modified face-lift (MFL) approach in head and neck cancer. This approach may have advantages over the conventional approach, especially in its superior aesthetic results. Objective: The fibular osseous or osteocutaneous free flap is a widely accepted option for the reconstruction of mandibular defects. Recently, we devised an RA or an MFL approach for neck dissection (ND) using an endoscopic or robotic surgical system. Here, we performed the reconstruction of a segmental mandibular defect with a fibular free flap using the RA or the MFL approach. Methods: A total of five patients underwent mandibular reconstruction with the RA or MFL approach for mandibular discontinuity, which developed after the surgical extirpation of head and neck cancer. We performed ND, segmental mandibulectomy, and the reconstruction of the mandibular defect via RA or MFL incisions. Results: An osseous free flap was used for the reconstruction in two patients and the osteocutaneous free flap was used in three patients. The mean operation times for mandibulectomy and ND were 82 (range 45–120) min and 156 (range 140–180) min, respectively. No significant complications were noted. All flaps survived successfully.

Occlusal guiding flange prosthesis for management of hemimandibulectomy-a case report

Surgical resection of the mandible due to presence of benign or malignant tumor is the most common. Depending upon the location and extent of the tumor in the mandible, various surgical treatment modalities like marginal, segmental, hemi, subtotal, or total mandibulectomy can be performed. Mandibular discontinuity defects present a major challenge to the rehabilitation team and to maxillofacial prosthodontist. Discontinuity of mandible after resection destroys balance and symmetry which leads to altered mandibular movements and deviation of the residual fragment towards the defective side. Variety of materials and techniques have used for the construction of prosthetic replacement of the acquired surgical defects. This case report describes prosthodontic management of a patient who has undergone hemi-mandibulectomy with mandibular guide flange prosthesis. To aid in moving the mandible normally without deviation during functions like speech and mastication. Keywords: Hemimandibulectomy, Guiding flange, Maxillofacial prosthesis

Prototyped grafting plate for reconstruction of mandibular defects

To esthetically and functionally restore a 40-mm canine mandibular discontinuity defect using a custom-made titanium bone-grafting plate in combination with autologous iliac bone grafts. Individualized titanium bone-grafting plates were manufactured using a series of techniques, including reverse engineering, computer aided design, rapid prototyping and titanium casting. A 40-mm discontinuous defect in the right mandibular body was created in 9 hybrid dogs. The defect was restored immediately using the customized plate in combination with autologous cancellous iliac blocks. Sequential radionuclide bone imaging was performed to evaluate the bone metabolism and reconstitution of the grafts. The specimens were evaluated by biomechanical testing, 3-dimensional microcomputed tomographic scanning, and histological examination. The results revealed that the symmetry of the mandibles was reconstructed using the customized grafting plate, and the bony continuity of the mandibles was restored. By 12 weeks after the operation, the cancellous iliac grafts became a hard bone block, which was of comparable strength to native mandibles. A fibrous tissue intermediate was found between the remodelled bone graft and the titanium plate. The results indicate that the prototyped grafting plate can be used to restore mandibular discontinuous defects, and satisfactory aesthetical and functional reconstruction can be achieved.

Reconstruction plates used in the surgery for mandibular discontinuity defect.

ObjectivesThe purpose of this study was to analyze the survival rate of reconstruction plates that were used to correct mandibular discontinuity defects.Materials and MethodsWe analyzed clinical and radiological data of 36 patients. Only discontinuous mandibular defect cases were included in the study. Reconstruction plate survival rate was analyzed according to age, gender, location of defect, defect size, and whether the patient underwent a bone graft procedure, coronoidectomy, and/or postoperative radiation therapy (RT).ResultsPlate-related complications developed in 8 patients, 7 of which underwent plate removal. No significant differences were found in plate survival rate according to age, gender, location of defect, defect size, or whether a bone graft procedure was performed. However, there were differences in the plate survival rate that depended on whether the patient underwent coronoidectomy or postoperative RT. In the early stages (9.25±5.10 months), plate fracture was the most common complication, but in the later stages (35.75±17.00 months), screw loosening was the most common complication.ConclusionIt is important to establish the time-related risk of complications such as plate fracture or screw loosening. Coronoidectomy should be considered in most cases to prevent complications. Postoperative RT can affect the survival rate and hazard rate after a reconstruction plate is fitted.

Reconstruction of mandibular defects using nonvascularized autogenous bone graft in nigerians.

Objectives:The aim of this study is to evaluate the success rate and complications of mandibular reconstruction with nonvascularized bone graft in Ile-Ife, Nigeria.Patients and Methods:A total of 25 patients who underwent reconstruction of mandibular discontinuity defects between January 2003 and February 2012, at the Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife constituted the study sample. Relevant information was retrieved from the patients’ records. This information include patients’ demographics (age and sex) as well as the type of mandibular defect, cause of the defect, type of mandibular resection done, source of the bone graft used, and the method of graft immobilization. Morbidity associated with the graft procedures were assessed by retrieving information on graft failures, length of hospital stay following surgery, rehabilitation device used and associated graft donor and recipient site complications.Result:There were 12 males and 13 females with a male:female ratio was 1:1.1. The age of the patients ranged from 13 to 73 years with a mean age for males 32.7 ± standard deviation (SD) 12.9 and for females 35.0 ± SD 17.1. Jaw defect was caused by resection for tumours and other jaw pathologies in 92% of cases. Complete symphyseal involvement defect was the most common defect recorded 11 (44%). Reconstruction with nonvascularized rib graft accounted for 68% of cases while iliac crest graft was used in 32% of the patients. Successful take of the grafts was recorded in 22 patients while three cases failed. Wound dehiscence (two patients) and postoperative wound infection (eight patients) were the most common complications recorded.Conclusion:The use of nonvascularized graft is still relevant in the reconstruction of large mandibular defects caused by surgical ablation of benign conditions in Nigerians. Precise surgical planning and execution, extended antibiotic therapy, and meticulous postoperative care contributed to the good outcome.

Implant Mandibular Rehabilitation Postoncologic Segmental Resection

In cases of reconstruction of a discontinuity defect of the mandible, the surgeon has a major responsibility to maximize function as well as cosmetics and to preserve quality of life, restoring mastication, speech, and appearance. Treatment of mandibular discontinuity defects is a complex process and, among other methods, includes the use of free vascularized flaps. A variety of donor sites have been used for this purpose, including the iliac crest, radius, scapula, and fibula.At this time, the iliac crest free flap represents a versatile reconstruction method after mandibular ablation. This article reports a clinical case using the iliac crest free flap for comprehensive reconstruction of discontinuity defects in the mandible after resections of an aggressive odontogenic tumor. The immediate implant positioning reduced the number of surgical procedures and the rehabilitation time.