Condylar Resorption After Orthognathic Surgery.

The aim was to postoperatively evaluate a conservative treatment approach to bilateral condylar resorption after orthognathic surgery. A retrospective study was carried out on 730 consecutive patients undergoing sagittal split osteotomy, 2013 to 2016. The mean follow-up period was 2.29 years. Clinical and radiographic findings of patients with postoperative bilateral condylar resorption were searched. Syndromic patients and patients with juvenile rheumatoid arthritis were excluded from this study. Of the 730 patients, 6 (0.82%) required treatments because of bilateral postoperative condylar resorption but had no surgery at the temporomandibular joint (TMJ). Five patients with TMJ symptoms because of postoperative condylar resorption were managed with conservative treatment. About 2 of the 6 patients were successfully retreated with orthognathic surgery in the upper jaw to close the open bite. The TMJ symptoms can successfully be managed with conservative therapy, whereas skeletal relapse can be retreated with orthognathic surgery in the upper jaw, depending on the amount of overjet. Patient undergoing orthognathic surgery may develop bilateral condylar resorption though the frequency is <1%, most of these patients can be managed conservatively.

Wide Intraoral Surgical Access to the Inferior Alveolar Nerve During Cryotherapy at the Infratemporal Fossa: Technical Modification.

Trigeminal neuralgia is characterized by unilateral pain in the region supplied by the sensory distribution of the fifth cranial nerve. Pharmacologic therapy is an adequate initial treatment option in 75% of patients. When the Jannetta surgical operation is not available or not indicated and when conservative treatment fails to relieve the pain or the medication has to be discontinued because of side effects, one of the remaining surgical options is cryosurgery in the peripherally distributed nerves that emanate from the trigeminal nerve. This technical note describes a perioperative method for exposing and mobilizing the inferior alveolar nerve (IAN) from its bony canal. This approach provided easy access to infratemporal fossa structures during cryotherapy. This technique represented a further development of the technique previously described by the authors. This method ensured direct visualization of the IAN and wide access to theinfratemporal fossa during IAN cryotherapy.

Biological profile of ameloblastoma and its location in the jaw in 1246 Nigerians.

OBJECTIVES: Ameloblastoma is a benign, slow-growing, locally invasive epithelial tumor of odontogenic origin, with unlimited growth capacity and a strong tendency to recur. This multicentric study analyzed ameloblastoma diagnosed in Nigeria among different ethnic groups. STUDY DESIGN: This retrospective study included ameloblastoma cases diagnosed from 1964 to 2017 at 10 hospitals or medical centers in Nigeria. Age, sex, tribe, and location of the ameloblastoma in the jaw were analyzed. Associations between variables were tested by using χ2 and Fisher's exact test. RESULTS: A total of 1246 ameloblastoma cases were recorded (mean patient age 32.51 ± 14.54 years; range 4-86 years; male-to-female ratio 1.2:1). Approximately 60% of ameloblastoma cases occurred in young adults (age range 18-40 years). Ninety-eight lesions were located in the maxilla and 1103 in the mandible; the posterior mandible was the most common site (31.3% on the right and 26.5% on the left, respectively), followed by the anterior (26.0%) mandible. No significant differences were noted in the distribution of ameloblastoma within the tribes with respect to age (P = .92) and sex (P = .71). CONCLUSIONS: The mandible is a common site of ameloblastoma in patients in Nigeria, and in most cases, it occurs in young adults. Early presentation, diagnosis, and treatment are important to reduce postoperative disfigurement and morbidity.

Use of Bone Grafts or Modified Bilateral Sagittal Split Osteotomy Technique in Large Mandibular Advancements Reduces the Risk of Persisting Mandibular Inferior Border Defects.

PURPOSE: Healing of the inferior border of the mandible can be compromised in large advancements, leaving an unesthetic defect at the inferior border. The objective of this study was to compare different bilateral sagittal split osteotomy (BSSO) techniques to prevent the incidence of lower border mandibular defects. MATERIALS AND METHODS: The authors undertook a retrospective multicenter cohort study comparing 3 BSSO techniques for advancements greater than 5 mm: traditional non-grafted BSSO (group A), traditional grafted BSSO (group B), and modified BSSO (group C). The space created by the mandibular advancement was measured. The presence or absence of a defect was determined 1 year after surgery by clinical and radiographic assessment. The bone defect outcome was associated with potential risk predictors (age, gender, side of SSO, and magnitude of mandibular advancement) by logistic regression analysis. RESULTS: A total of 1,002 operative sites in 501 patients were included in the study. Age (mean, 26.8 yr; standard deviation, 11 yr), gender (310 female, 191 male), and mandibular advancement (right, 9.3 mm; left, 10 mm) were similar among groups (P > .05). The proportions of postsurgical lower border mandibular defects were 54.5% in group A, 1.3% in group B, and 10.6% in group C. The traditional grafted and modified BSSO techniques were significantly more effective in preventing the incidence of mandibular lower border defects compared with the traditional non-grafted BSSO technique (P < .05). CONCLUSION: Surgeons are advised that the traditional non-grafted BSSO technique produces a large proportion of mandibular lower border defects. Use of bone grafts or the modified BSSO technique in mandibular advancements greater than 10 mm markedly decreases the risk of persisting mandibular inferior border defects.

Assessment of occlusion with the T-Scan system in patients undergoing orthognathic surgery.

Dental occlusion varies among individuals, and achieving correct physiological occlusion after osteotomy is essential for the complex functioning of the stomatognathic system. The T-Scan system records the centre of force, first contact, maximum bite force, and maximum intercuspation. The aim of the present study was to investigate the usefulness and consistency of T-Scan in assessing occlusion before and after orthognathic surgery. Occlusal information was evaluated for 30 healthy adults with normal occlusion and 40 patients undergoing orthognathic surgery. T-Scan had a high degree of reliability for consecutive measurements (Pearson correlation, r = 0.98). For most parameters, occlusal distribution was better after surgery than before surgery. More teeth contributed to occlusion at maximum intercuspation after surgery than before surgery (14 vs. 10). In addition, the difference in the posterior force distribution was reduced after surgery (17.6 ± 13.8 vs. 22.7 ± 21.4 before surgery), indicating better occlusal force distribution after surgery. The maximum percentage force on teeth (p = 0.004) and the number of teeth contributing to occlusion (p < 0.001) also differed significantly. Thus, T-Scan is good for assessing occlusal discrepancies and can be used to portray the pre- and post-operative occlusal contact distribution during treatment planning and follow-up.

Achieved chin position after genioplasty follows the planned horizontal change better than the planned vertical change.

PURPOSE: The soft-tissue pogonion closely follows changes of the bony pogonion, but it is unknown how often an augmented bony pogonion reaches the intended position. Here we assessed the agreement between planned surgical changes and achieved results in chin surgery. MATERIALS AND METHODS: Surgical treatment was planned based on clinical examination, cast model analysis, and cephalometric image analysis. The mobile chin segment was stabilized using one chin plate. Preoperative and postoperative cephalometric X-ray images were digitized, and cephalometric tracing was performed. We calculated and analyzed the changes between the preoperative and postoperative images as well as between planned genioplasty movements and actual surgical changes in the horizontal and vertical directions. RESULTS: This study included 36 patients. In 34 patients, the absolute mean horizontal difference was less than 2 mm. We found a higher range of absolute error in vertical (0.00-5.60) compared to horizontal (0.01-3.64) movement. There was no significant difference between the mean planned chin movement and the mean achieved position with regard to the horizontal and vertical movement (p = 0.97 and 0.79, respectively). CONCLUSIONS: The mean values for linear difference in both the horizontal and vertical directions were in line with the acceptable mean of ≤2 mm proposed in the literature.

Pragmatic approach to manage new oral anticoagulants in patients undergoing dental extractions: a prospective case-control study.

OBJECTIVES: The aim of this study was to validate a standardized pragmatic approach to manage new oral anticoagulants (NOACs) in patients who undergo dental extractions. MATERIALS AND METHODS: This prospective case-control study in patients undergoing dental extraction included 26 patients (mean age 76 years, 57% male) treated with dabigatran, rivaroxaban, or apixaban and 26 matched controls. Regardless of timing of extraction, drug regimen, or renal function, patients were instructed to skip only the dose on the morning of the procedure. A procedural bleeding score was recorded and early and delayed bleeding was assessed at day 1 and day 7. Bleeding events were compared with a prospectively matched control group not taking any antithrombotic drug. RESULTS: There was no difference in the procedural bleeding score or in early bleeding events (5 in both groups). However, delayed bleeding occurred more frequently in anticoagulated compared to non-anticoagulated patients (7 versus none, p = 0.01). CONCLUSIONS: Skipping the morning dose of NOACs avoids excess bleeding during and early after the procedure. However, anticoagulated patients had an increased risk of delayed bleedings. Further study is needed to determine the optimal post-procedural management. CLINICAL RELEVANCE: This is the first prospective study for the management of patients on NOACs undergoing dental extraction. Our pragmatic approach, omitting only a single morning dose, can guide clinical practice. Both patients and physicians should be aware of the increased delayed bleeding risk.

Intraoperative Computed Tomography in Bilateral Sagittal Split Osteotomy.

OBJECTIVES: The objective of the study was to show the importance of intraoperative computed tomography as an aid for ensuring inferior alveolar nerve safety during bilateral sagittal split osteotomy. MATERIALS AND METHODS: This study included ten patients who underwent bilateral sagittal split osteotomy procedure. All patients were treated for orthognathic reasons. The unerupted lower third molars, if present, were removed at least 6 months prior to Sagittal Split Osteotomy. The Sagittal Split Osteotomy surgical technique was previously described in detail. Each patient underwent computed tomography with an Artis Zeego multi-axis system (Siemens AG, Healthcare Sector, Henkestrasse 127 D-91052 Erlangen, Germany) at the beginning of the operation and immediately after placement of the osteosynthesis plates and screws. The neurosensory tests consisted of a light touch test using the 5.07/10-g Semmes Weinstein monofilament (Stoelting Co, Wood Dale, IL), and patient self-reporting. RESULTS: Eight (80 %) patients presented with hypoesthesia of lower lip at 6 weeks follow up. At 6 month follow up only two patients (20 %) presented with diminished sensation in the lower lip. Labial sensibility was normal in all patients at the last follow-up visit. CONCLUSION: Intraoperative computed tomography enables immediate assessment of treatment and the option to modify the treatment if necessary. Our results indicate that intra-operative computed tomography would be a helpful procedure during orthognathic surgery to improve the postoperative health of the inferior alveolar nerve.

Neuropathy of Trigeminal Nerve Branches After Oral and Maxillofacial Treatment.

OBJECTIVE: To report the incidence of trigeminal neuropathy seen among new patients in a referral center within a period of 1 year (2013). The cause of damage, method of management and treatment outcome was assessed after 1-year follow-up. MATERIALS AND METHODS: The records of all new patients visiting the oral and maxillofacial unit of the University hospital of Leuven in 2013 were screened for a history of damage to branches of the trigeminal nerve. The selected records were examined and the duration of nerve damage, received treatment as well as the outcome of the neuropathy after treatment was noted after 1-year follow-up. RESULTS: 56 patients (21 males, 35 females) from 7602 new patients had symptoms of damage to the trigeminal nerve branch. These symptoms persist in more than one-third of the patients [21/56 (37.5 %)] after 1-year follow-up. The least recovery is seen from oral surgery, implant placement, orthognathic surgery and tooth extraction. After 1 year 85 % (12/14) of neuropathic pain cases still have their symptoms as compared to 19 % (5/26) of patients with hypoesthesia. CONCLUSION: This study shows a low incidence of nerve damage among the new patients presenting in oral and maxillofacial surgery clinic (<1 %); however, one-third of patients who sustain nerve damage never recover fully. Early diagnosis of the cause of neuropathy is essential. There is a need to objectively assess all patients with symptoms of trigeminal nerve damage before, during and after treatment.

Modified Mandibular Inferior Border Sagittal Split Osteotomy Reduces Postoperative Risk for Developing Inferior Border Defects.

PURPOSE: The purpose of this study was to evaluate the impact of a modified sagittal split osteotomy (SSO) surgical technique on the incidence of persisting inferior border defects. The secondary aim was to identify risk factors associated with the development of these complications. MATERIALS AND METHODS: The patient charts and radiographs of 276 consecutive patients who underwent bilateral SSO, performed by a single surgeon in 2 different centers from July 2012 to September 2014, were retrospectively examined. The predictor variable was length of advancement. The outcome variable was the presence or absence of an inferior border defect. Other variables included age and side of the jaw. In all cases the same surgical technique was used. All statistical analyses were performed using SAS software, version 9.4 (SAS Institute, Cary, NC). RESULTS: The analysis included 408 operation sites in 204 patients (132 female and 72 male patients; median age, 22 years; age range, 13 to 66 years). In 5.1% of operation sites an osseous defect at the lower border of the mandible was observed. Age at the time of surgery (P < .0001) and length of advancement (P = .0111) were identified as risk factors for the development of a persisting osseous defect at the inferior border of the osteotomy gap after SSO. CONCLUSIONS: This study confirms the findings previously reported by our research group that the modified inferior border osteotomy technique in SSO results in a substantial lower frequency of persisting inferior border defects. Surgeons are advised to ensure that the lingual cortex of the inferior border is not included in the split during mandibular advancements, and in cases in which the advancement is more than 10 mm and/or the patient is older than 30 years, surgeons might want to consider using a bone graft or a bone graft substitute.

Possible association between mandibular repositioning device for sleep apnea and osseous lytic lesion with fracture of the coronoid process of the mandible: A case report.

Mandibular repositioning devices (MRDs) increase the patency of the upper airway by repositioning the mandible forward, resulting in displacement of the oropharyngeal tissues preventing upper airway collapsibility. Mandibular anterior repositioning is counteracted by muscle force from the temporalis muscle. A 39-year-old man had an osteolytic lesion with fracture of the coronoid process of the mandible secondary to wearing a MRD for sleep apnea. Continuous stress generated on the coronoid process temporalis muscle resulted in osteolysis and fracture of the coronoid process on the patient's right side, resulting in swelling and limited ability to open his mouth. The patient was managed with intravenous antibiotics to control the osteomyelitis and surgical debridement, with removal of the coronoid process of the mandible. It is unclear why the fracture only occurred on the right side. Pathologic fracture of the coronoid process due to chronic stress and secondary osteomyelitis is a rare severe complication of treatment for obstructive sleep apnea syndrome with a MRD.

Visualization techniques of the inferior alveolar nerve (IAN): a narrative review.

PURPOSE: The purpose of this study was to produce an overview of the present visualization techniques of the inferior alveolar nerve (IAN) in order to reduce the rates of nerve damage after third molar (M3) removal and bilateral sagittal split osteotomy (BSSO). METHODS: An electronic literature search was performed of the English-language scientific literature published prior to December 31, 2014 using the LIMO KU Leuven search platform. Information on the specifications of the different imaging techniques, their clinical application, advantages, disadvantages, and duration was extracted from 11 reports. RESULTS: Five methods for IAN visualization were obtained from the search results, which are cone-beam computed tomography (CBCT) and automatic extraction of the IAN canal using computed tomography (CT), magnetic resonance imaging (MRI), panoramic radiography, endoscopy, and ultrasonographic visualization. CONCLUSION: The results of this study suggest that high-resolution MRI is the most commonly used method for direct visualization of the IAN. Six out of the eleven manuscripts use this technique. Recently, there have been some (experimental) modifications to the conventional MRI in the form of diffusion tensor tractography (DTT), phase-contrast magnetic resonance angiography (PC-MRA), and dental MRI. Future studies will focus on an intraoperative application of MRI to visualize the IAN during surgery.

Coronectomy of Deeply Impacted Lower Third Molar: Incidence of Outcomes and Complications after One Year Follow-Up.

OBJECTIVES: The purpose of present study was to assess the surgical management of impacted third molar with proximity to the inferior alveolar nerve and complications associated with coronectomy in a series of patients undergoing third molar surgery. MATERIAL AND METHODS: The position of the mandibular canal in relation to the mandibular third molar region and mandibular foramen in the front part of the mandible (i.e., third molar in close proximity to the inferior alveolar nerve [IAN] or not) was identified on panoramic radiographs of patients scheduled for third molar extraction. RESULTS: Close proximity to the IAN was observed in 64 patients (35 females, 29 males) with an impacted mandibular third molar. Coronectomy was performed in these patients. The most common complication was tooth migration away from the mandibular canal (n = 14), followed by root exposure (n = 5). Re-operation to remove the root was performed in cases with periapical infection and root exposure. CONCLUSIONS: The results indicate that coronectomy can be considered a reasonable and safe treatment alternative for patients who demonstrate elevated risk for injury to the inferior alveolar nerve with removal of the third molars. Coronectomy did not increase the incidence of damage to the inferior alveolar nerve and would be safer than complete extraction in situations in which the root of the mandibular third molar overlaps or is in close proximity to the mandibular canal.

Accuracy of Dental Implant Placement Using CBCT-Derived Mucosa-Supported Stereolithographic Template.

PURPOSE: The aim of the present in vivo study was to evaluate whether a difference exists between the maxilla and the mandible regarding the precision of implant placement utilizing a cone beam computed tomography (CBCT)-derived mucosa-supported stereolithographic (SLA) template. MATERIALS AND METHODS: Eighty implants (44 maxilla, 36 mandible) were placed in 18 fully edentulous jaws (10 maxillas, eight mandibles) using a mucosa-supported SLA surgical template. A voxel-based registration technique was applied to match the postoperative and preoperative CBCT scans. RESULTS: Vertical deviation (p = .026) at the implant hex and angular deviation (p = .0188) were significantly lower in the maxilla than in the mandible. The global linear deviation and lateral deviation at the implant hex were not significantly different. At the implant apex, the average maximum vertical deviation was within 1 mm (0.1-4.6 mm). The average maximum lateral deviation was 1.8 mm (0.9-5.5 mm) in the maxilla and 2.3 mm (0.5-5.5 mm) in the mandible when a 15-mm-long implant was placed. CONCLUSIONS: When using CBCT-derived mucosa-supported SLA templates, clinicians should be aware of differences in the angular deviation of the implants in the mandible and maxilla. The average maximum linear deviation should be considered as a safety margin at the implant apex.

Accuracy of a Dedicated Bone-Supported Surgical Template for Dental Implant Placement with Direct Visual Control.

The aim of this study is to evaluate feasibility and accuracy of dental implant placement utilizing a dedicated bone-supported surgical template. Thirty-eight implants (sixteen in maxilla, twenty-two in mandible) were placed in seven fully edentulous jaws (three maxillae, four mandibles) guided by the designed bone-supported surgical template. A voxel-based registration technique was applied to match pre- and post-operative CBCT scans. The mean angular deviation and mean linear deviation at the implant hex and apex were 6.4 ± 3.7° (0.7°-14.8°), 1.47 ± 0.64 mm (0.5-2.56 mm) and 1.70 ± 1.01 mm (0.71-4.39 mm), respectively. The presented bone-supported surgical template showed acceptable accuracy for clinical use. In return for reduced accuracy, clinicians gain accessibility when using this type of surgical template for both the maxilla and the mandible. This is particularly important in patients with reduced mouth opening.

Attachment rate of the inferior alveolar nerve to buccal plate during bilateral sagittal split osteotomy influences self-reported sensory impairment.

This study was aimed to investigate a modified buccal osteotomy technique and whether the integrity of the lingual part of the lower border influences the attachment of the neurovascular bundle to the proximal segment of the mandible during a sagittal split osteotomy without increasing the number of bad splits. The presence of self-reported sensibility disturbance in the lower lip at the last follow-up visit was assessed. This study included 220 and 133 patients with bilateral sagittal split osteotomy undergoing the classical and the new modified buccal osteotomy techniques, respectively. In the new technique, the lower border is divided into a lingual fragment that remains incorporated in the tooth-bearing fragment and a buccal fragment that comes with the proximal fragment (buccal plate). In the classical technique, the inferior alveolar nerve was attached to the proximal segment of the mandible in more than one third of operation sites (36.36% on the right and 40.91% on the left) compared with less than one fourth of the operation sites using the new technique (9.73% on the right and 23.01% on the left). The overall figure of self-reported changed sensibility was 09.40% (12/128) in the new technique compared to 15.12% in the classical technique. We present a suitable improvement to the classical buccal osteotomy technique that allows less manipulation and injury of the inferior alveolar nerve with consequent reduction in self-reported postoperative changes in lower lip sensation

Safe surgical access to the mandibular nerve at the infratemporal fossae.

Some anatomic patterns formed by the anterior border of the ascending ramus relative to the mandibular canal can cause nerve complications during surgery. We determined the frequency of obstructive anatomy in patients undergoing jaw surgery, and we described a perioperative method for a bilateral sagittal split osteotomy that ensured inferior alveolar nerve (IAN) protection. The anatomy of the anterior border of the ascending ramus of the mandible was examined on axial and cross-sectional cone beam computed tomographic images of 114 consecutive patients undergoing bilateral sagittal split osteotomies. The thickness of the anterior border of the ascending ramus determined whether the mandibular foramen could be visualized (pattern A) or was obscured (pattern B). Patients with pattern B anatomy received a perioperative procedure. Direct visualization of the mandibular foramen was achieved in 100% of patients with pattern A anatomy. We examined 228 anterior borders of the ascending ramus of the mandible relative to the mandibular foramen in 114 patients. Pattern A was observed in 146 cases (64%); pattern B, in 82 (36%) cases. The use of the nerve hook resulted in no injuries to the IAN in all cases. The described procedure ensured direct visualization of the IAN, which prevented inadvertent damage to the IAN during instrumentation and surgical procedures at the mandibular foramen.

Osseous reconstruction using an occlusive titanium membrane following marginal mandibulectomy: proof of principle.

Guided bone regeneration using barrier membranes is useful in bone augmentation. In contrast to flexible membranes, stiff membranes such as titanium membranes are capable of maintaining sufficient space underneath them. We report a case of bone regeneration under an occlusive titanium membrane following marginal mandibulectomy in a 50-year-old patient with odontogenic keratocyst. Preoperative analysis of the anatomical conditions was evaluated with panoramic radiographs and spiral computer tomography (CT) scan. The digital data from the CT scan were transferred to a personal computer. Using Simplant software, a mirror image of the right mandible was constructed from which a custom-made titanium membrane was made. The cyst with the remaining inferior alveolar nerve was removed and curettage of the lesion was performed under general anesthesia. The definitive titanium plate was inserted and fixated with osteosynthesis screws, and then removed 5 years later. Postoperative CT scanning showed good healing, bone growth under the titanium plate, and no evidence of residual cyst The titanium plate reinforced the mandibular skeleton and restored the shape of the mandible and facial symmetry; it also promoted new bone formation to fill in the mandibular defects.

The accuracy of image-guided navigation for maxillary positioning in bimaxillary surgery.

The aim of our study was to evaluate the accuracy of image-guided maxillary positioning in sagittal, vertical, and mediolateral direction. Between May 2011 and July 2012, 17 patients (11 males, 6 females) underwent bimaxillary surgery with the use of intraoperative surgical navigation. During Le Fort I osteotomy, the Kolibri navigation system was used to measure movement of the maxilla at the edge of the upper central upper incisor in sagittal (buccal surface), vertical (incisor edge), and mediolateral (dental midline) direction. Six weeks after surgery, a postoperative CBCT scan was taken and registered to the preoperative cone-beam computed tomography scan to identify the actual surgical movement of the maxilla. Student 2-tailed paired t test was used to evaluate differences between the measured result from navigation system and actual surgical movement of the maxilla, which were 0.44 ± 0.35 mm (P = 0.82) in the sagittal, 0.50 ± 0.35 mm (P = 0.85) in the vertical, and 0.56 ± 0.36 mm (P = 0.81) in the mediolateral direction. Our finding demonstrates that intraoperative computer navigation is a promising tool for measuring the surgical change of the maxilla in bimaxillary surgery.