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external oblique ridge [keywords]
- Nonsurgical correction of a Class III malocclusion in an adult by miniscrew-assisted mandibular dentition distalization. [Case Reports, Journal Article]
- Am J Orthod Dentofacial Orthop 2013 Jun; 143(6):877-87.
This article reports the successful use of miniscrews in the mandible to treat a 20-year-old Mongolian woman with a chief complaint of anterior crossbite. The patient had a skeletal Class III malocclusion with a mildly protrusive mandible, an anterior crossbite, and a deviated midline. In light of the advantages for reconstruction of the occlusal plane and distal en-masse movement of the mandibular arch, we used a multiloop edgewise archwire in the initial stage. However, the maxillary incisors were in excessive labioversion accompanied by little retraction of the mandibular incisors; these results were obviously not satisfying after 4 months of multiloop edgewise archwire treatment. Two miniscrews were subsequently implanted vertically in the external oblique ridge areas of the bilateral mandibular ramus as skeletal anchorage for en-masse distalization of the mandibular dentition. During treatment, the mandibular anterior teeth were retracted about 4.0 mm without negative lingual inclinations. The movement of the mandibular first molar was almost bodily translation. The maxillary incisors maintained good inclinations by rotating their brackets 180° along with the outstanding performance of the beta-titanium wire. The patient received a harmonious facial balance, an attractive smile, and ideal occlusal relationships. The outcome was stable after 1 year of retention. Our results suggest that the application of miniscrews in the posterior area of the mandible is an effective approach for Class III camouflage treatment. This technique requires minimal compliance and is particularly useful for correcting Class III patients with mild mandibular protrusion and minor crowding.
- [Study of the appearance difference of lower complete denture between functional and anatomic impression techniques]. [English Abstract, Journal Article]
- Shanghai Kou Qiang Yi Xue 2012 Apr; 21(2):170-4.
To compare the difference in oblique external ridge, oblique internal ridge and alveolar process crest of lower complete denture base made through functional impression and anatomic impression techniques.Fifteen patients were chosen to treat with two kinds of complete dentures through functional impression and anatomic impression technique respectively. 3D laser scanner was used to scan the three-dimensional model of the denture base and the differences of the surface structural between two techniques in alveolar process crest, external and internal oblique ridges were analyzed, using paired t test with SPSS 12.0 software package.Between the two techniques, there were significant differences in the areas of internal and external oblique ridge(P<0.01); there was no significant difference in the main support areas(P>0.05).The results explain why there is less tenderness when functional impression technique is applied. The differences measured also indicate that sufficient buffering should be made in external and internal oblique ridge areas in clinic.
- Treatment of mandibular angle fractures - linea obliqua plate versus grid plate. [Comparative Study, Journal Article]
- J Craniomaxillofac Surg 2012 Dec; 40(8):807-11.
To compare treatment outcomes, handling and long term results between two osseo-fixation systems for mandibular angle fractures - the external oblique ridge (external oblique) plate and the grid plate.Sixty patients with mandibular angle fracture were analyzed regarding their operative treatment: 30 patients were treated with an external oblique plate and compared to 30 patients treated with a grid plate on the vestibular cortex. The follow up period was at least 1 year for both groups and the following complications were noted: infection, abnormality in fracture healing, nonunion, pain, hypoaesthesia and dysocclusion.The overall average operation time (from intubation to extubation) was 102.1 min (± 44.1 min). Single sided fractures treated with the grid plate needed in average 81.07 min (± 37.9 min) of operation time while single sided fractures treated with the external oblique plate needed 89.3 min (± 42.2 min). In multiple mandibular fractures, no significant change in the operation time between either plating system was found (118.8 ± 35.2 min). After the follow up period fracture healing was considered clinically complete in all patients, but complications occurred significantly more often in the external oblique group (13.3%; N=8) than in the grid plate group (0%; N=0).Isolated mandibular angle fractures can be more effectively treated using grid plates than using other osteosynthesis techniques. It is an easy to use alternative to conventional miniplate systems with good clinical outcome and fewer complications. An angulated burr and screwdriver has to be used to put on the plate laterally.
- [The stress distribution of mandibular alveolar mucosa under functional impressive complete denture studied by 3-D finite element analysis]. [English Abstract, Journal Article, Research Support, Non-U.S. Gov't]
- Shanghai Kou Qiang Yi Xue 2012 Feb; 21(1):31-5.
To analyze the stress distribution and displacement of the mandibular alveolar mucosa under functional impressive complete denture.CT images were processed by Mimics and Geomagic studio, and the solid models and 3-D finite element models were established by Unigraphics NX. 3-D finite element analysis (3-D FEA) was used to study the stress distribution and displacement on the mandibular alveolar mucosa under functional impressive complete denture and anatomic impressive complete denture.The stress distribution on the mandibular alveolar mucosa under two types of complete denture were consistent, and arranged from large to small order as follow: alveolar process crest of molar area, alveolar process crest of anterior area, external oblique ridge and internal oblique ridge. At alveolar process crest and internal oblique ridge, the stress and Z-axis displacement of functional impressive complete denture were less than those of anatomic impressive complete denture.During masticatory period, the stress distribution on the mandibular alveolar mucosa under functional impressive complete denture is more even and more comprehensive than that under anatomic one.
- Intraoral external oblique ridge compared with transbuccal lateral cortical plate fixation for the treatment of fractures of the mandibular angle: prospective randomised trial. [Journal Article, Randomized Controlled Trial]
- Br J Oral Maxillofac Surg 2012 Jun; 50(4):344-9.
Since the initial description by Michelet et al. and research by Champy et al. the placement of a single, four-hole, monocortical, osteosynthesis plate has been considered an acceptable method of fixation for a fracture of the mandibular angle. We investigated the null hypothesis that there is no difference in the incidence of postoperative removal of an infected plate between miniplates placed on the mandibular external oblique ridge and those placed on the buccal surface of the mandible through a transbuccal approach to treat a fracture of the angle of the mandible. Patients were randomised to having their angle fractures treated with a ridge plate placed intraorally or transbucally. Other variables were investigated including the effect of smoking, drinking alcohol, oral hygiene, and the method of holding the reduction on removal of the plate, occlusal outcome, and degree of preoperative anatomical displacement and postoperative reduction. We also studied the operating time required for the two techniques, the effect of the presence and consequent removal of a wisdom tooth in the line of the fracture, and the effect of delay in taking the patient to theatre for subsequent removal of the plate for infection. Of the 261 angle fractures 34 (13%) plates were removed because of infection, and 6 of these (18%) required a further period of fixation, such as intermaxillary fixation, to treat non-union. The transbuccal plate had a significantly lower postoperative infection rate (6/124, 5%) than the ridge plate (28/137, 20%) (p=0.001). Smoking adversely affected the healing of angle fractures (p=0.000). Displacement of fractures is related to the infection rate (p=0.003), and there are no significant relations between delay in going to theatre or the presence and potential removal of a wisdom tooth in the line of the fracture and infection rate. There was a highly significant difference between the rate of removal of plates placed intraorally on the external oblique ridge, and plates placed transbucally (p=0.000). Transbuccal plates were far less likely to need removal for infection than ridge plates, odds ratio 5.05.
- Retrospective study of bone grafting procedures before implant placement. [Comparative Study, Journal Article]
- Implant Dent 2010 Aug; 19(4):342-50.
The aim of this retrospective study was to evaluate morbidity and possible complications in augmentation procedures before implant placement.Records from 93 consecutive patients with indication for autogenous bone grafting before implant placement, treated at Department of Oral and Maxillofacial Surgery and Implantology of Uberlândia Federal University, in a 7-year period (July 2000 until July 2007), were reviewed. The need for bone grafting was defined by the impossibility of installing implants of adequate length or diameter to fulfill prosthetic requirements or for aesthetic reasons.A total of 136 bone grafting procedures were performed. The mandibular external oblique line and ascending ramus were the most frequently used donor areas (59.64%) and block grafts (67.64%) were the most frequently used type of graft, frequently from the mandibular external oblique line/ascending ramus (52.18%). Platelet-rich plasma was used in 20.1% of all procedures, usually associated with particulate bone grafts. Maxillary procedures represented the majority of surgeries (75%), but with fewer complications compared with the mandible. Sinus mucosa perforation was the most frequent complication in maxillary procedures, whereas graft exposure was the most common complication in mandible.Alveolar reconstruction using autogenous bone followed by implant placement is a reliable treatment for patients with insufficient bone. Complications and morbidity were frequently observed. However, in only 6.6% of all procedures, the final rehabilitation with dental implants was not possible.
- Finite element analysis of the human mandible to assess the effect of removing an impacted third molar. [Journal Article]
- J Can Dent Assoc 2010.:a72.
Finite element analysis (FEA) was used to generate 3-dimensional models of a human mandible with impacted third molars. The aim was to analyze the effects of removing various amounts of bone around an impacted mandibular third molar and to predict the possibility of iatrogenic fracture.Data were acquired from cone beam computed tomography (CBCT) scans of a patient using numerically calculated mechanical parameters. Virtual surgery was then performed on the mandibular models, and standardized chewing forces were applied to the resulting simulations.The modelling showed that the highest stress during normal clenching occurred if the surgical procedure involved the external oblique ridge. The peak stress occurred at the site of removal of the third molar, during contralateral loading of the mandible.Use of CBCT allowed production of high-quality models of an individual patient and simulation of various surgical scenarios. FEA identified the accumulation of stress and strain at specific parts of the mandible and predicted the responses of bone to mechanical activity. FEA could prove useful to dental practitioners in the future to predict the likelihood of iatrogenic fracture of the jaws after surgical removal of mandibular bone, such as occurs when the third molar is removed. This may allow dentists to change their approach to tooth removal in certain cases.
- Distance between external cortical bone and mandibular canal for harvesting ramus graft: a human cadaver study. [Comparative Study, Journal Article, Research Support, Non-U.S. Gov't]
- J Periodontol 2010 Feb; 81(2):239-43.
The aims of this study are to determine the distance of the external surface of the buccal cortical plate to the inferior alveolar canal in the mandibular molar region and to propose a safe thickness for harvesting a mandibular ramus block graft.Thirty-four cadavers consisting of 26 dentate jaws and eight jaws in the edentulous molar region were used in this study. All mandibular ramus grafts were harvested by one investigator with the grafts extending from the external oblique ridge (EOR) and 15 mm inferiorly in the apico-coronal direction and extending from the mid-buccal aspect of the first molar to the mid-buccal aspect of the third molar in the mesio-distal direction. Measurements were made of the cortical bone thickness of the harvested ramus graft and from the cemento-enamel junction (CEJ) to the EOR, the CEJ to the mandibular border, and the CEJ to the inferior alveolar nerve (IAN).The average buccal cortical plate thickness in dentate mandibles was 2.76 +/- 0.13 mm, whereas in edentulous posterior mandibles it was 2.52 +/- 0.32 mm. The IANs were exposed in all jaws but were intact.The safe thickness to harvest ramus grafts was determined to be 2.5 to 3.0 mm.
- [Clinical effects of ridge augmentation with the half-columnar shaped mandibular bone block for the placement of dental implants]. [English Abstract, Evaluation Studies, Journal Article]
- Beijing Da Xue Xue Bao 2010 Feb 18; 42(1):94-7.
To evaluate the treatment effects of the half-columnar shaped mandibular block bone onlay grafting technique for augmentation of the resorbed maxillary anterior alveolar ridge after single tooth missing.A total of 15 sites of 14 patients received ridge augmentation surgeries. The recipient sites were prepared with trephines, the half-columnar shaped bone blocks were harvested from the ramus and external oblique ridges with trephines according to diameters of the recipient sites. The bone blocks were placed as lateral onlay grafts on recipient beds and secured by means of titanium screws. Particulate bone was added and absorbable membranes were used to stabilize and protect the grafts. After a mean interval of 4.5 months of healing the flaps were re-opened, the screws were removed and non-submerged implants were placed. The width and height of the alveolar ridges were recorded. After 3 months, implant-supported crowns were provided to the patients. One year later, the peri-impant condition and the marginal bone resorption on the proximal sites were observed.Mean lateral augmentation obtained at the time of bone grafting was (3.8 + or - 0.8) mm, 5 out of 15 sites exhibited a mean of 3 mm of vertical augmentation. The mean healing time was 4.5 months, the mean percentage of horizontal and vertical bone resorption in the mean time were 8% and 7% respectively. No major complications were recorded at donor sites. No implant was lost during the study period. Clinical parameters and probing depth (< or = 4 mm) demonstrated the presence of a healthy peri-implant mucosa after 1 year of prosthetic reconstruction. The clinical and radiographic bone observations showed no more than 1.2 mm of resorption after bone graft and implant placement.The half-columnar shaped mandibular bone graft (from the ramus and external oblique ridge) is a promising technique for bone augmentation in localized alveolar ridge defects after single tooth missing. This procedure offers easy access, good bone quantity for localized repair, low morbidity, decreased complaints of postoperative sensory disturbances or discomfort, minimal graft resorption, and a shorter healing time as compared with other methods for bone repair.
- Temporomandibular joint reconstruction with costochondral graft using modified approach. [Journal Article]
- Int J Oral Maxillofac Surg 2008 Oct; 37(10):897-902.
12 patients presenting with long standing temporomandibular joint (TMJ) ankylosis were treated with a costochondral graft inserted through a modified approach. The age of the patients ranged from 5 to 17 years. A preauricular incision was made for resection of the ankylosed condyle. After release of the ankylosis the contralateral rib was harvested with costal cartilage. An intra-oral incision was made along the external oblique ridge to the mucobuccal fold and was used for resection of the coronoid process and insertion and fixation of the graft. The graft was fixed with a minimum of three titanium screws. The patients were instructed to start physiotherapy 1 week postoperatively and were followed up clinically and radiographically using 3D CT. Postoperative results were encouraging, the graft took well in all patients without postoperative infection or graft rejection. The graft was properly positioned in all cases. There were no visible scars as the preauricular scar is relatively hidden, no possibility of damaging the facial nerve or the marginal mandibular branch and shorter operating time.