Modified Blair Approach for the Treatment of Mandibular Condyle Fractures.

PURPOSE: The management of fractures of the condyle of the mandible has been a topic of debate and still no consensus exists in the literature about the most appropriate approach. The objective of this study was to evaluate the efficacy and safety of the modified Blair approach for the open reduction and internal fixation of mandibular condyle fractures. METHODS: A retrospective study was conducted on 18 patients with 20 mandibular condyle fractures from 2014 to 2020. All patients were treated surgically using the modified Blair approach. Postoperative occlusion status and mouth opening were assessed for treatment outcomes. Also, the rate of complications such as facial nerve paralysis, wound infection, hematoma, salivary fistula, Frey syndrome, and greater auricular nerve paraeesthesia evaluated. RESULTS: Seventeen out of 18 patients (94.4%) achieved their original pretraumatic occlusion after the surgery. One patient (5.5%) had postoperative occlusal interference due to premature dental contact. The maximal postoperative interincisal distance was measured with a range between 33 and 41 mm (mean 37.6 mm). One patient (5.6%) had transient facial nerve palsy. Also, salivary fistula developed in 1 (5.6%) patient in the postoperative period. CONCLUSION: The results of this study revealed that the modified Blair approach provides satisfactory clinical outcomes with low complication rates and may offer an alternative, safe, and effective method for open reduction and internal fixation of mandibular condyle fracture.

Treatment efficiency of activator and skeletal anchored Forsus Fatigue Resistant Device appliances.

OBJECTIVES: The aim of the study was to investigate the treatment efficiency of miniplate anchored Forsus Fatigue Resistant Device (MAF) as compared with the activator appliance. MATERIALS AND METHODS: Mandibular retrognathia was treated with two methods, the MAF group (8 girls, 11 boys, mean age 13.03 ± 0.69 years) and the activator group (7 girls, 12 boys, mean age 12.68 ± 0.73 years). An untreated control group (9 girls, 10 boys, mean age 12.95 ± 0.73 years) was constructed to eliminate growth-related changes through the American Association of Orthodontists Foundation Legacy Collection. Data of 114 lateral cephalograms were analyzed. RESULTS: The inhibition of the maxillary growth was greater in the MAF group, whereas forward displacement of the mandible was higher in the activator group (P < 0.05). Sagittal maxillomandibular relation was improved similarly in both treatment groups (P < 0.05). Mandibular length was increased in both treatment groups with the highest increase in the activator group (P < 0.05). Retroclination of the incisors was observed in the MAF group (P < 0.05). The upper lip was retruded in the MAF group and lower lip was protruded in the activator group (P < 0.05). CONCLUSION: The activator created greater mandibular changes, whereas the MAF provides somewhat smaller mandibular changes due to the restriction caused by retroclined maxillary incisors. CLINICAL RELEVANCE: Although both MAF and activator treatments caused favorable maxillomandibular changes, new treatment alternatives that reduce dentoalveolar side effects and eliminate patient cooperation are still required to achieve skeletal correction in class II malocclusion treatment in growing patients.

Comparison of Success Rate of Dental Implants Placed in Autogenous Bone Graft Regenerated Areas and Pristine Bone.

Autogenous bone grafting still has been considered as the "gold standard" and wildly used in the case of alveolar bone reconstruction. The aim of the present study is to evaluate the success rate of implants placed in autogenous block augmented ridges and implants placed in pristine bone (PB). This study included 113 patients. Fifty-three patients were treated with autogenous block grafts and particulate bone, after 6 months of healing implant placements were performed in autogenous bone augmented (ABA) areas. In 60 patients implant placement was performed, with no need for grafting and implants were placed into the PB. Follow-up data (pain, mobility, exudation from peri-implant space, success rate, marginal bone resorption) were collected after 5 years of prosthetic loading. The cumulative implant success rate at the 5-year examination was 92.45% for the ABA group and 85% for PB group. There were 3 failed implants in the ABA group and 3 in PB group. Average marginal bone loss was 1.47 mm on ABA group and 1.58 mm on PB group. No statistically significant differences for pain, exudation from peri-implant space, implant mobility, implant success, peri-implant bone loss parameters, and patient satisfaction level were found between groups. The obtained data demonstrated that the success rate of implants placed in regenerated areas are very similar to the success rate of implants those placed in PB.

Effect of Induced Membrane on Guided Bone Regeneration in an Experimental Calvarial Model.

OBJECTIVE: The aim of this study was to evaluate the effect of induced membrane on guided bone regeneration and to compare its effect with poly-tetra-flourur-ethylene (PTFE) membrane and collagen membrane. METHODS: Sixteen white Vienna rabbits were used for experiments. Initially 1 defect was created on the parietal bone of all animals and cement was placed inside the defects. After 8 weeks, the bone cements were removed, without damaging the induced membrane formed in the defect cavity. And then 2 more defects were created. All defects were filled with xsenogenic graft materials and were covered with newly formed induced membrane, d-PTFE membrane and collagen membrane. Eight animals were sacrificed at 4th week and other 8 animals were sacrificed at 8th week and all bone specimens were histologically evaluated. RESULTS: New bone formation and bone marrow ratios were significantly higher in induced membrane and d-PTFE membrane group compared to collagen membrane group (P < 0.05) at 4th week. Mature bone ratios were significantly higher in induced membrane and d-PTFE membrane group compared to collagen membrane group (P < 0.05) at 8th week. The best CD31 value was detected with d-PTFE membrane group at 4th week and with induced membrane at 8th week. CONCLUSION: Induced membrane can act as a strong barrier membrane and stimulate bone regeneration. Induced membrane technique can be accepted as a good alternative for the reconstruction of critical size defects in maxillofacial region.

Preventive and therapeutic effects of relaxin on bisphosphonate related osteonecrosis of the jaw: an experimental study in rats / Efeitos preventivos e terapêuticos da relaxina na osteonecrose da mandíbula relacionada a bisfosfonatos: um estudo experimental em ratos

Objective: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a challenging complication of chronic bisphosphonate (BP) use. The hormone relaxin is able to induce the multistep differentiation process of human osteoclastogenesis, exhibits antifibrotic and anti-inflammatory actions, and promotes vasodilatation, wound healing, and angiogenesis. The present study aimed to evaluate the effects of relaxin in the prevention and management of BRONJ. Material and Methods: Thirty-six male Sprague Dawley rats were randomly divided into four groups. Rats in group 1 (n = 10) received relaxin and BP simultaneously for 12 weeks. Rats in group 2 (n = 10) received injections of BP for 12 weeks, followed by relaxin for another 12 weeks. Rats in group 3 (n = 10) received only BP injections, and those in group 4 (control, n = 6) received only saline. Necrosis and inflammation in the rats' mandibles were evaluated as indicators of BRONJ. Results: Necrosis and inflammation were not detected in group 1 (BP + relaxin). In group 3 (BP only), incidence rates of necrosis and inflammation were 90% and 60%, respectively. Conclusions: Our findings suggest that relaxin may be potently effective in preventing BRONJ and have some benefit in the treatment of existing BRONJ (AU)

Objetivo: A osteonecrose da mandíbula relacionada ao bisfosfonato (BRONJ) é uma desafiadora complicação do uso crônico de bisfosfonato (BP). O hormônio relaxina é capaz de induzir o processo múltiplo de diferenciação da osteoclastogênese humana, exibe ações anti-fibróticas e anti-inflamatórias e promove vasodilatação, cicatrização de feridas e angiogênese. O presente estudo teve como objetivo avaliar os efeitos da relaxina na prevenção e tratamento do BRONJ. Material e Métodos: Trinta e seis ratos Sprague Dawley machos foram divididos aleatoriamente em quatro grupos. Os ratos do grupo 1 (n = 10) receberam relaxina e BP simultaneamente por 12 semanas. Os ratos do grupo 2 (n = 10) receberam injeções de BP por 12 semanas, seguidos de relaxina por mais 12 semanas. Os ratos do grupo 3 (n = 10) receberam apenas injeções de BP e os do grupo 4 (controle, n = 6) receberam apenas solução salina. Necrose e inflamação nas mandíbulas dos ratos foram avaliadas como indicadores de BRONJ. Resultados: Necrose e inflamação não foram detectadas no grupo 1 (BP + relaxina). No grupo 3 (somente BP), as taxas de incidência de necrose e inflamação foram de 90% e 60%, respectivamente. Conclusões: Nossos resultados sugerem que a relaxina pode ser potentemente eficaz na prevenção do BRONJ e ter algum benefício no tratamento do BRONJ existente.(AU)

Effects of Platelet-Rich Fibrin Membrane on Sciatic Nerve Regeneration.

Alternative treatment approaches to improve the regeneration capacity of damaged peripheral nerves are currently under investigation. The objective of the present study was to evaluate the effects of platelet-rich fibrin (PRF) membrane after sciatic nerve crush injury in rabbits by histomorphometric and electromyographic analysis. The left sciatic nerves of 20 male Vienna rabbits were clamped for 30 seconds to induce crush injuries. Animals were randomly divided into 2 groups: PRF and control. For each animal in the PRF group, a PRF membrane was wrapped around the injured part of the sciatic nerve to form a tube. No additional treatment was performed in the control group. After a 12-week healing period, tissue samples from the injured nerve region were harvested and the g-ratio of axons, axon density, and impulse transmission changes were evaluated. Analysis revealed that axon density differences were not statistically significant between groups (P = 0.139). The rate of nerve fibers with optimum g-ratio was significantly lower in the PRF group than in the control group (P = 0.02). Conduction velocity differences between groups were not statistically significant. Although PRF application has previously shown positive regeneration effects on maxillofacial tissues, local PRF membrane application in tube form did not show any histomorphometric or functional improvement in peripheral nerve crush injury recovery.

Comparison of Tunnel and Crestal Incision Techniques in Reconstruction of Localized Alveolar Defects.

PURPOSE: The aim of this study was to compare the complication rates of recipient sites prepared using two incision techniques: crestal and tunnel. MATERIALS AND METHODS: In this prospective study, patients underwent augmentation procedures (68 patients; 75 sites) by the same surgeon that were performed consecutively using the crestal incision technique (27 horizontal, 10 vertical; crestal group) or the tunnel incision technique (27 horizontal, 11 vertical; tunnel group). Autogenous bone block grafts were harvested with a piezoelectric surgical device, and the grafts were fixed at the recipient sites by two titanium screws in both groups. The authors evaluated minor exposure, transient paresthesia, major exposure, permanent paresthesia, gingival recession at adjacent teeth, surgery time, and visual analog scale pain scores. RESULTS: Soft tissue dehiscence and graft failure were significantly lower in patients undergoing the tunnel technique. CONCLUSION: The tunnel incision technique significantly decreased soft tissue exposure, the most common complication of augmentation procedures with autogenous onlay bone grafts. This technique should be considered an alternative to the crestal incision technique for preparation of the recipient site.

Positive effect of platelet rich fibrin on osseointegration

BACKGROUND: Leukocyte-platelet rich fibrin (L-PRF) is a second generation platelet concentrate clinically used to accelerate tissue healing and bone regeneration. Achieving reduced implant osseointegration time could provide immediate or early loading of implants. The aim of this study was to evaluate the L-PRF-induced osseointegration and bone-implant contact (BIC) in an experimental animal model. MATERIAL AND METHODS: Twelve 4-month-old New Zealand white rabbits were used. Following general anesthesia, 3-5 mL of blood was obtained from the central artery in rabbit ear and L-PRF was prepared. Two implant cavities (5 mm long and 3 mm in diameter) were created in each tibia with a total of four cavities in each animal. Two of these cavities were selected and covered with PRF (test group). The remaining L-PRF was used to soak the implants placed into the L-PRF covered sockets. Other cavities were left as controls. In total, 48 implants were placed. Animals were sacrificed after two, three, or four weeks. Histological samples were obtained and periimplant tissues were histomorphometrically evaluated for bone-to-implant contact and new bone formation. RESULTS: Histomorphometric analyses of the defects revealed that the L-PRF was detectable up to the second week. Application of L-PRF increased the rate and amount of new bone formation in the experimental group compared to the control group. Bone-to-implant contact was enhanced when the surface was prewetted with LPRF (p < 0.01). CONCLUSIONS: The results of this study demonstrated that L-PRF application may increases amount and rate of new bone formation during the early healing period and provides a faster osseointegration around implants

Stress Distribution on Short Implants at Maxillary Posterior Alveolar Bone Model With Different Bone-to-Implant Contact Ratio: Finite Element Analysis.

The aim of this study was to evaluate the stress distribution of the short dental implants and bone-to-implant contact ratios in the posterior maxilla using 3-dimensional (3D) finite element models. Two different 3D maxillary posterior bone segments were modeled. Group 1 was composed of a bone segment consisting of cortical bone and type IV cancellous bone with 100% bone-to-implant contact. Group 2 was composed of a bone segment consisting of cortical bone and type IV cancellous bone including spherical bone design and homogenous tubular hollow spaced structures with 30% spherical porosities and 70% bone-to-implant contact ratio. Four-millimeter-diameter and 5-mm-height dental implants were assumed to be osseointegrated and placed at the center of the segments. Lateral occlusal bite force (300 N) was applied at a 25° inclination to the implants long axis. The maximum von Mises stresses in cortical and cancellous bones and implant-abutment complex were calculated. The von Mises stress values on the implants and the cancellous bone around the implants of the 70% bone-to-implant contact group were almost 3 times higher compared with the values of the 100% bone-to-implant contact group. For clinical reality, use of the 70% model for finite element analysis simulation of the posterior maxilla region better represents real alveolar bone and the increased stress and strain distributions evaluated on the cortical and cancellous bone around the dental implants.

Change in inferior sclera exposure following Le Fort I osteotomy in patients with midfacial retrognathia.

PURPOSE: For facial esthetic reasons, no sclera should be exposed above or below the irises when the head of a patient who has a normal skeletal pattern is in a neutral position and the eyelids are in a relaxed position. This study evaluated the decrease in sclera exposure after maxillary advancement or impaction in patients with midfacial hypoplasia. PATIENTS AND METHODS: Forty-seven consecutive patients (24 male, 23 female) who underwent Le Fort I osteotomy were included. The patients were divided into 2 groups according to type of maxillary movement: group I underwent maxillary advancement (n = 23) and group II underwent maxillary advancement and impaction surgery (n = 24). Standardized preoperative and 6-month postoperative photographs of the frontal view of patients were evaluated using Adobe Photoshop CS5. The proportion of inferior sclera exposure to eye height was determined, and the proportional difference between the preoperative and postoperative orbital views was statistically analyzed. RESULTS: The proportion of inferior sclera exposure to eye height decreased by a ratio of 0.07 (P = .001) in the right and left eyes of the 47 patients, with an average maxillary advancement of 6.1 mm. The proportion of inferior sclera exposure to eye height of the right and left eyes decreased from 0.1 to 0.02 and from 0.09 to 0.02, respectively, in group I (P = .001). The proportion of inferior sclera exposure to eye height decreased in group II by a ratio of 0.06 in the right and left eyes (P = .001). CONCLUSION: Inferior sclera exposure in patients with midfacial hypoplasia and retrognathia decreases significantly in accordance with the change in the lower eyelid position after maxillary advancement or impaction surgeries.

Does the titanium plate fixation of symphyseal fracture affect mandibular growth?

The effect of metallic fixation on growth is a major concern in children and is not yet clear. The aim of this study was to evaluate the effect of metallic fixation of mandibular symphyseal fracture on mandibular growth.Eighteen 90-day-old growing white New Zealand rabbits weighing 1.6 to 2.5 kg were included in this study and divided into 2 groups of 9 subjects. In the experimental group, animals underwent mandibular osteotomy, simulating a symphyseal fracture on the midline of mandibular symphysis. The bone segments were fixed with microplates and microscrews (1.6 mm).In the control group, the same surgical incision without performing symphyseal osteotomy was conducted, and 2 screws were inserted on each side of the symphyseal midline.Digital cephalometric and submentovertex radiographs were taken before the operation and at postoperative 6 months for each animal in 2 groups, and cephalometric measurements were performed. The distance between the centers of the head of 2 screws measured at the end of surgery in the control group was compared with measurements at 6 months after surgery. Obtained data were statistically analyzed.There is no statistically significant difference between the 2 groups for growth amount of both sides of the mandible. Difference of ANS-Id (the most anterior points of nasal bone, the most anterior point on the alveolar bone between the lower incisors) and Cd-Id (the uppermost and most distal point of the mandibular condyle, the most anterior point on the alveolar bone between the lower incisors) values of the 2 groups is not statistically significant (P > 0.05).The distance between the 2 screws at the first application significantly increased at the postoperative sixth month (P < 0.05). Metallic fixation of mandibular symphyseal fracture does not affect the vertical and sagittal mandibular growth in growing rabbits.

Repositioning of the masseter muscle and its effect on skeletal growth.

OBJECTIVE: The aim of this study was to establish a model to aid in understanding the influences of bilateral masseter muscle relocation on the bone and muscle, and to determine the influences of bilateral masseter muscle relocation on mandibular growth pattern in rabbits. STUDY DESIGN: Ten 3-month-old growing white New Zealand rabbits were included. Digital lateral cephalometric radiographs were obtained before operation and 6 months after surgery. The Co-Gn, gonial angle, FMA, ANS-Me, GoGn-SN, Y-axis, and Jarabak values were compared by using Student t test. RESULTS: There was a statistically significant difference between the groups in the gonial angle (P < .05). Vertical height values (GoGn-SN, FMA, Y-axis, and ANS-Me) showed statistically significant increases in animals in the control group. In contrast, vertical height values in the experimental group did not show statistically significant increase. CONCLUSIONS: Anterior relocation of the masseteric muscle influenced the direction of vertical growth significantly compared with the control group.

Comparison of fixation stability of resorbable versus titanium plate and screws in mandibular angle fractures.

PURPOSE: The aim of this study was to compare the fixation reliability and stability of titanium and resorbable plates and screws by simulating chewing forces. MATERIALS AND METHODS: Mandibular angle fractures in 11 sheep hemimandibles were fixed with 4-hole straight titanium plates and 2.0 x 7-mm titanium screws; in addition, 11 hemimandibles were fixed with 4-hole straight resorbable plates and 2.5 x 6-mm resorbable screws according to the Champy technique. The hemimandibles were mounted with a fixation device in a servohydraulic testing unit for compressive testing. Displacement values under 20, 60, 100, 120, 150, and 200 N; maximum displacements; and maximum forces that the model could resist before breakage were recorded and compared. RESULTS: Significant differences were found between resorbable and titanium plates and screws at all forces (20, 60, 100, 120, 150, and 200 N) (P < .05). We found no statistically significant differences in the breaking force and maximum displacement values (displacement values at the breaking forces) between the groups. CONCLUSIONS: The stability of mandibular angle fractures with titanium miniplates under simulated chewing forces was significantly higher than with the resorbable system. Metallic and resorbable fixation systems cannot be used interchangeably to treat mandibular angle fractures under similar loading conditions.

Effects of titanium plate fixation on mandibular growth in a rabbit model.

PURPOSE: The purpose of this study was to evaluate the effect of metallic rigid fixation of mandibular corpus fracture on mandibular growth in growing rabbits. MATERIALS AND METHODS: Thirteen 90-day-old white New Zealand rabbits weighing 2 to 2.6 kg were included in this study. Unilateral mandibular fractures were created in all of the animals and fixed with microplates and screws. Microplates that had been adapted for fixation of the left (experimental) side were also used as a template for the drilling procedure on the right (control) side of the mandible. The plate was then removed, and screws were inserted. Digital submentovertex radiographs of each animal were taken before the operation and 6 months after surgery. Cephalometric values were analyzed. The distance between the centers of the 2 screws on the right side of the mandible was measured with a caliper in all samples, and values were compared with measurements taken from the left (experimental) side of the mandible upon which the plates had been placed. RESULTS: The mean amount of mandibular growth was 4.38+/-2.43 mm on the right (control) side and 4.64+/-2.27 mm on the left (experimental) side. This difference was not statistically significant (P> .05). The distance between the 2 screws was 13.89+/-0.23 mm on the experimental side and 13.44+/-0.46 mm on the control side. This difference was statistically significant (P< .05). CONCLUSIONS: Metallic fixation of a mandibular body fracture did not cause mandibular asymmetry or restricted mandibular growth in growing rabbits in this relatively small sample.

Alveolar cleft closure by distraction osteogenesis with skeletal anchorage during consolidation.

Intraoral distraction osteogenesis (DO) has been widely used for the reconstruction of various dentoalveolar defects. However, its use in the management of alveolar clefts is relatively new. This method allows the closure of the cleft via the regeneration of new alveolar bone and attached gingiva through the distraction of a dento-osseous segment. It eliminates the need for a donor site for autogenous bone grafting and possible graft failure. However, the relatively long consolidation period required for the use of intraoral DO devices may result in soft tissue irritation that would compromise patient cooperation, especially in children. In the case presented, the intraoral DO technique was used for the treatment of a unilateral residual alveolar cleft and an implant was subsequently placed in the regenerated bone. A miniplate was also placed to serve as a skeletal anchor to enable the early removal of the distractor device. The distractor was removed before the beginning of the consolidation phase.

Comparison of intraosseous and extraosseous alveolar distraction osteogenesis.

PURPOSE: To evaluate and compare intraosseous and extraosseous alveolar distraction osteogenesis. PATIENTS AND METHODS: Twenty-three distractors (13 intraosseous; 10 extraosseous) were placed in 21 patients (9 males, 12 females; age range, 12 to 55 years; mean age, 37.9 years) with alveolar ridge deficiencies. Periodontal disease and alveolar resorption following tooth removal was the most common reason for alveolar distraction osteogenesis (n = 14). The length of the segments were less than 2 cm in 15 defects, 2 to 4 cm in 2 defects and more than 4 cm in 6 defects. At the end of consolidation period 25 implants were inserted to the intraosseous group and 17 implants to the extraosseous group. RESULTS: In 21 patients with 23 distracted sites, the mean alveolar distraction was 11.6 mm (range, 5 to 20 mm). The overall complication rates in the intraosseous and extraosseous groups were 61.5% and 50%, respectively. Complications of both groups were mostly minor (95.8%; tilting of the segment, rod interference), only 1 segment fracture in the intraosseous group (4.2%) was considered as a major complication. The most common minor complication in the intraosseous group was tilting of the distracted segment (38.3%). Rod interference with the opposing arch (30%) was the most common minor complication in the extraosseous group. The survival rates of the implants for intraosseous and extraosseous groups were 88% and 94%, respectively. Although complication rate was higher and implant success rate was lower in the intraosseous group, there was no statistical significance between the groups (P > .05). CONCLUSION: Intraosseous and extraosseous alveolar distractors presented no statistically significant complication rates and implant success rates. The clinician must choose an ideal size and type of the distractor according to the defect size, shape, patient tolerance, and distance to the opposing arch.