Autotransplantation With a 3-Dimensionally Printed Replica of the Donor Tooth Minimizes Extra-Alveolar Time and Intraoperative Fitting Attempts: A Multicenter Prospective Study of 100 Transplanted Teeth.

PURPOSE: Three-dimensional (3D) autotransplantation is a technique for surgical transposition of a tooth to another site within one patient, using 3D printed replicas of the donor tooth. In this study, we evaluated intraoperative experiences during 3D autotransplantation of teeth. MATERIALS AND METHODS: A multicenter prospective clinical study was implemented. All procedures were performed using preoperative cone-beam computed tomography imaging and computer-assisted design with computer-assisted manufacturing resulting in a 3D replica of the donor tooth. RESULTS: The 100 autotransplantation procedures (79 patients) included canines, premolars, molars, and 1 supernumerary tooth. In 82% of the procedures, the transplantation was performed with an extra-alveolar time of less than 1 minute and an immediate good fit of the donor tooth. In 14%, the extra-alveolar time was 1 to 3 minutes or multiple fitting attempts were necessary. In 4%, the extra-alveolar time exceeded 3 minutes. Difficulties during the procedures were caused by movement artifacts on the preoperative cone-beam computed tomography imaging, a long interval between the imaging and the procedure, or insufficient bone volume at the recipient site. CONCLUSIONS: The use of a 3D printed donor tooth replica during autotransplantation procedures minimized the extra-alveolar time and intraoperative fitting attempts of transplants. This facilitated a quick and reliable treatment and enabled more difficult procedures.

Root Elongation After Autotransplantation in 58 Transplanted Premolars: The Radiographic Width of the Apex as a Predictor.

PURPOSE: Autotransplantation of premolars with incomplete root development is a reliable treatment option for tooth replacement. Nevertheless, little is known about root development after transplantation of teeth. The aim of this study was to evaluate preoperative root development stage and radiographic width of the apex as predictors for root elongation after autotransplantation. MATERIALS AND METHODS: A retrospective cohort study was implemented and composed of patients who underwent autotransplantation of at least 1 premolar. Using panoramic radiographs (orthopantomograms), calibrated measurements were taken to record the root development stage of the donor tooth, width of the apex, and root length of the transplanted tooth. RESULTS: Forty-five patients (58 transplants) were included. Mean follow-up time was 12 months (range, 4 to 26 months). Fifty-three transplanted teeth (91.4%) showed root elongation. Mean root elongation at end of follow-up was 1.9 mm (range, 0.0 to 4.3 mm). A wide-open apex before transplantation was significantly associated with root elongation after autotransplantation (P < .01). Root development stage (P = .82) did not show significant associations with root elongation. CONCLUSIONS: A wide-open apex (>2.0 mm) is an important predictor of root elongation after autotransplantation of premolars. This might be a better predictor for root development than preoperative root development stage.

Replacing Heavily Damaged Teeth by Third Molar Autotransplantation With the Use of Cone-Beam Computed Tomography and Rapid Prototyping.

This article describes the autotransplantation of third molars to replace heavily damaged premolars and molars. Specifically, this article reports on the use of preoperative cone-beam computed tomographic planning and 3-dimensional (3D) printed replicas of donor teeth to prepare artificial tooth sockets. In the present case, an 18-year-old patient underwent autotransplantation of 3 third molars to replace 1 premolar and 2 molars that were heavily damaged after trauma. Approximately 1 year after the traumatic incident, autotransplantation with the help of 3D planning and rapid prototyping was performed. The right maxillary third molar replaced the right maxillary first premolar. The 2 mandibular wisdom teeth replaced the left mandibular first and second molars. During the surgical procedure, artificial tooth sockets were prepared with the help of 3D printed donor tooth copies to prevent iatrogenic damage to the actual donor teeth. These replicas of the donor teeth were designed based on the preoperative cone-beam computed tomogram and manufactured with the help of 3D printing techniques. The use of a replica of the donor tooth resulted in a predictable and straightforward procedure, with extra-alveolar times shorter than 2 minutes for all transplantations. The transplanted teeth were placed in infraocclusion and fixed with a suture splint. Postoperative follow-up showed physiologic integration of the transplanted teeth and a successful outcome for all transplants. In conclusion, this technique facilitates a straightforward and predictable procedure for autotransplantation of third molars. The use of printed analogues of the donor teeth decreases the risk of iatrogenic damage and the extra-alveolar time of the transplanted tooth is minimized. This facilitates a successful outcome.

Neuropathic Pain Due to Iatrogenic Lingual Nerve Lesion: Nerve Grafting to Reduce Otherwise Untreatable Pain.

Iatrogenic lingual nerve lesion is a well-known and unfortunate complication after mandibular third molar removal. Occasionally, the nerve injury can cause severe neuropathic pain.Here, the authors present the history of 2 patients with lingual nerve injury due to mandibular third molar removal, and with severe neuropathic pain in the craniomandibular region. Pharmacotherapy and physiotherapy did not reduce the pain, and ultimately, the lingual nerve was surgically explored. Scar tissue and a lingual nerve neuroma were observed and resected in both patients.In the first patient, the gap between the nerve stumps was bridged with an autologous sural nerve graft. In the second patient, some continuity of the lingual nerve was preserved and the resected part was substituted with an autologous sural nerve graft. Significant pain reduction was achieved in both patients and no further medical treatment was necessary at the end of follow-up.These reports show that lingual nerve reconstruction can be a successful therapy in patients experiencing severe neuropathic pain after iatrogenic lingual nerve injury. Different treatment options for neuropathic pain due to lingual nerve injury are discussed.

Impact of adenotonsillectomy on the dentofacial development of obstructed children: a systematic review and meta-analysis.

BACKGROUND: Dentofacial deformities frequently require orthodontic treatment. Understanding of preventable risk factors is essential for reducing treatment need. Upper airway obstruction (for example due to hypertrophic adenoids and/or tonsils) has been hypothesized to be a risk factor. OBJECTIVES: This systematic review aimed to reflect the contemporary evidence on the risk of obstruction by hypertrophic adenoids and/or tonsils, by assessing the dentofacial changes after adeno- and/or tonsillectomy. SEARCH METHODS: A systematic search of electronic databases and manual searches of grey literature and reference lists of relevant studies was performed. SELECTION CRITERIA: No restrictions were placed on publication language. Experimental, cohort, and case-control studies were eligible for inclusion. Studies reporting associations between treatment of adenoid and/or tonsil hypertrophy and dentofacial deformities in children were included. Adenoidectomy and/or tonsillectomy were performed in all patients; outcomes were assessed before and after surgery. DATA COLLECTION AND ANALYSIS: Data were extracted by two independent reviewers in duplicate. The Cochrane Risk of Bias tool was used to assess the methodological quality of the included papers. RESULTS: The initial search yielded 1196 papers, of which 16 articles could be included. All papers described controlled prospective cohort studies, reporting on a total of 461 patients and controls (mean age, 4.1-13.9 years). A descriptive and quantitative synthesis of dentofacial change postoperatively is presented. Consistent findings across studies were the normalisation towards labial inclination of the upper and lower incisors and towards a more horizontal mandibular growth pattern. No change in vertical or sagittal maxillary growth was reported after surgical treatment. Post-surgical increase in maxillary archwidth and decrease in lateral crossbite-frequency were consistently reported. Findings on overjet, overbite and angle from S to N to B (SNB-angle), mandibular arch width, and gonial angle were inconsistent. CONCLUSION: The available literature suggests that treatment of hypertrophic adenoids and/or tonsils affects dentofacial deformity. This could indicate a relationship between nasopharyngeal obstruction (i.e. upper airway obstruction) and the dentofacial growth pattern. However, the high risk of bias and considerable diversity between studies impedes a clear conclusion regarding this effect. REGISTRATION: None.

Success and survival of autotransplanted premolars and molars during short-term clinical follow-up.

AIM: Autotransplantation is an elegant therapy for single tooth replacement that is too often overlooked in patients with missing teeth. Especially, autotransplantation of third molars to replace heavily damaged or missing molars is often not considered. This study investigated the success and survival of autotransplanted premolars and molars during clinical follow-up. MATERIALS AND METHODS: The medical files and radiographs of 97 consecutive patients were retrospectively investigated. Seventy-nine patients could be included in this study. Autotransplantation of 97 premolars and 14 molars (111 procedures) was performed. The median follow-up time was equal to 13.4 months. RESULTS: In this study group, 82.0% of transplanted teeth were classified as successful and 98.2% were present at the end of follow-up. No transplants were extracted during standard follow-up of 1 year. The 5-year tooth survival probability was 87.5% (95%CI 64.5-100). One premolar and one molar were extracted, respectively, 4 and 9 years after autotransplantation. CONCLUSIONS: These results show that autotransplantation is associated with high success and survival rates and can provide a reliable treatment option for tooth replacement in young patients. Further research regarding long-term outcome is necessary to assess if the transplanted teeth function as normal teeth after clinical follow-up.

Autotransplantation of Premolars With a 3-Dimensional Printed Titanium Replica of the Donor Tooth Functioning as a Surgical Guide: Proof of Concept.

PURPOSE: Autotransplantation of premolars is a good treatment option for young patients who have missing teeth. This study evaluated the use of a preoperatively 3-dimensional (3D)-printed replica of the donor tooth that functions as a surgical guide during autotransplantation. MATERIALS AND METHODS: Five consecutive procedures were prospectively observed. Transplantations of maxillary premolars with optimal root development were included in this study. A 3D-printed replica of the donor tooth was used to prepare a precisely fitting new alveolus at the recipient site before extracting the donor tooth. Procedure time, extra-alveolar time, and number of attempts needed to achieve a good fit of the donor tooth in the new alveolus were recorded. RESULTS: For each transplantation procedure, the surgical time was shorter than 30 minutes. An immediate good fit of the donor tooth in the new alveolus was achieved with an extra-alveolar time shorter than 1 minute for all transplantations. CONCLUSION: These results show that the extra-alveolar time is very short when the surgical guide is used; therefore, the chance of iatrogenic damage to the donor tooth is minimized. The use of a replica of the donor tooth makes the autotransplantation procedure easier for the surgeon and facilitates optimal placement of the transplant.

Angled Osteotomy Design Aimed to Influence the Lingual Fracture Line in Bilateral Sagittal Split Osteotomy: A Human Cadaveric Study.

PURPOSE: The traditional osteotomy design in the bilateral sagittal split osteotomy includes a horizontal lingual bone cut, a connecting sagittal bone cut, and a vertical buccal bone cut perpendicular to the inferior mandibular cortex. The buccal bone cut extends as an inferior border cut into the lingual cortex. This study investigated a modified osteotomy design including an angled oblique buccal bone cut that extended as a posteriorly aimed inferior border cut near the masseteric tuberosity. MATERIALS AND METHODS: The authors implemented a randomized controlled study. The study sample was comprised of 28 cadaveric dentulous mandibles. The primary outcome variable was the pattern of lingual fracture induced using the conventional (n = 14) and modified (n = 14) osteotomy designs. The secondary outcome variables included the incidence of bad splits and the status of the inferior alveolar nerve (IAN). Descriptive and bivariate statistics were computed. RESULTS: The angled osteotomy design resulted in a significantly larger number of the lingual fractures originating from the inferior border cut (odds ratio [OR] = 1.54; 95% confidence interval [CI], 1.27-1.86; P < .01), with a significantly more posterior relation of the fracture line to the mandibular canal (OR = 2.11; 95% CI, 1.22-3.63; P < .01) and foramen (OR = 1.99; 95% CI, 1.28-3.08; P < .01). No bad splits occurred with the angled design, whereas 3 bad splits occurred with the conventional design, although this difference was not statistically significant (OR = 1.11; 95% CI, 0.99-1.25; P = .07). IAN status was comparable between designs, although the nerve more frequently required manipulation from the proximal mandibular segment when the conventional design was used (OR = 1.21; 95% CI, 0.99-1.47; P = .06). CONCLUSION: The results suggest that the angled osteotomy design promotes a more posterior lingual fracture originating from the inferior border cut and a trend was apparent that this also might decrease the incidence of bad splits and IAN entrapment. These results must be carefully extrapolated to the clinical setting, with future studies clarifying these findings.

Cross-cultural validity of the Dutch sleep-related breathing disorder scale of the Pediatric Sleep Questionnaire in a general population.

BACKGROUND: Pediatric sleep-disordered breathing is associated with multiple health problems. Polysomnography is the reference standard for identifying this disorder, but availability is limited. Therefore, an alternative screening tool is needed. Globally, the Sleep-Related Breathing Disorder scale of the Pediatric Sleep Questionnaire (PSQ) has proven to be a feasible tool. Consequently, this study aimed to translate and culturally adapt the PSQ into Dutch and then to examine the cultural validity, internal consistency, and test-retest reliability of the Dutch version among a general population visiting oral healthcare centers. METHODS: The translation, review, adaptation, pretest, and documentation approach was used to ensure cross-cultural adaptation of the PSQ. Then, 220 children (2.4-18 years) were sampled for clinimetric evaluation. We estimated the cross-cultural validity by comparing the factor analyses of the original PSQ and the Dutch version. Reliability was assessed using Cronbach's alpha, Spearman's correlation, the intraclass correlation coefficient, the standard error of measurement, and a Bland-Altman plot. RESULTS: The factor loading patterns of the Dutch version matched with the original study around the four predetermined factors: breathing, sleepiness, behavior, and other. The internal consistency, with a Cronbach's α of 0.77, was acceptable. The test-retest reliability with an intraclass correlation coefficient and Spearman's correlation of 0.89 and 0.93, respectively, was good to excellent. CONCLUSIONS: Cultural adaptation was ensured and the results support cross-cultural validity, internal consistency, and test-retest reliability of the Dutch Sleep-Related Breathing Disorder scale of the PSQ. This questionnaire could therefore be a valuable tool for screening disordered breathing in Dutch children.

[Bimaxillary osteotomy for obstructive sleep apnoea]. / Bimaxillaire osteotomie bij obstructieve slaapapneu.

Bimaxillary osteotomy for obstructive sleep apnoea Objective To gain insight into postoperative results of bimaxillary osteotomy in patients with obstructive sleep apnoea (OSA). Design Retrospective patient series. Method All patients with OSA who had undergone a bimaxillary osteotomy in the Amphia Hospital in Breda in the Netherlands in the past 4 years were eligible for inclusion. The primary outcome measures were the apnoea-hypopnoea index (AHI), a decrease in symptoms and the success of the operation. Results In the past 4 years, 22 patients with OSA underwent a bimaxillary osteotomy in the Amphia Hospital in Breda. We further analysed data from 18 patients. All patients had a normal to moderately elevated BMI. 94.1% had a complete absence or a marked decline in symptoms postoperatively. In 23.5% the cure was complete (AHI < 5/h) and treatment was successful in 52.9% of the patients (> 50% reduction in AHI and AHI < 20/h). The average AHI decreased from 38/h preoperatively to 11/h postoperatively. Conclusion Bimaxillary osteotomy is currently often regarded as a final treatment option for patients with OSA. Even in these patients with a relatively complex condition the results of the operation are relatively good. For treatment providers it is important to recognise patients who might benefit from a bimaxillary osteotomy, such as patients with OSA and retrognathia.

Custom Made Replacement of the Mandibular Condyle in a Case of Fibrous Dysplasia with Cystic Degeneration; A Case Report.

This paper describes a rare case of fibrous dysplasia with cystic degeneration in the mandibular condyle. Diagnostic and therapeutic considerations are discussed. A 40-year old woman presented with pain near the region of her right ear. Physical and radiographic examination showed no abnormalities besides the presence of a mixed radiopaque/radiolucent expansive lesion of the right condyle. Pathologic examination showed high bone-turnover with bone formation. Bone scintigraphy showed a monostotic active fibrous lesion in the right part of the mandible. Bisphosphonate treatment did not sufficiently treat the patient's symptoms and physiotherapy to treat craniomandibular dysfunction as a factor in the pain was also unsuccessful. The patient later developed an acute external otitis due to a narrowed outer ear canal and had to be admitted to the hospital for treatment with intravenous antibiotics. Approximately two years after first presentation, resection of the affected bone (condylectomy) and reconstruction with a custom total joint prosthesis was indicated due to repeated functional deficits with considerable morbidity. Pathologic examination of the resected mandibular condyle showed increased bone formation including formation of neocortex and some cystic formation. This was diagnosed as fibrous dysplasia with cystic degeneration. Approximately two years after surgery, the patient functioned well.

Risk factors for common complications associated with bilateral sagittal split osteotomy: A literature review and meta-analysis.

The most common complications that are associated with bilateral sagittal split osteotomy are: bad splits, postoperative infection, removal of osteosynthesis material, and neurosensory disturbances of the lower lip. Particularly in elective orthognathic surgery, it is important that surgeons inform their patients about the risk of these complications and attempt to minimize these risks. The purpose of this literature review and meta-analysis is to provide an overview of these common complications and their risk factors. After a systematic electronic database search, 59 studies were identified and included in this review. For each complication, a pooled mean incidence was computed. Both the pooled study group and the pooled 'complication group' were analysed. The mean incidences for bad split (2.3% per SSO), postoperative infection (9.6% per patient), removal of the osteosynthesis material (11.2% per patient), and neurosensory disturbances of the lower lip (33.9% per patient) are reported. Regularly reported risk factors for complications were the patient's age, smoking habits, presence of third molars, the surgical technique and type of osteosynthesis material. This information may help the surgeon to minimize the risk of these complications and inform the patient about the risks of complications associated with bilateral sagittal split osteotomy.

Removal of osteosynthesis material because of symptoms after Le Fort I osteotomy: A retrospective study of 158 patients.

The aim of this study was to analyse the incidence of removal of MESH plates because of symptoms after Le Fort I osteotomy (LF1). The medical files of patients treated with LF1 were retrospectively reviewed. The occurrence of MESH plate removal, indication for removal and time between insertion and removal were noted. The medical literature was reviewed to quantify the reported incidences of removal of titanium osteosynthesis material after LF1. A total of 158 patients were included in this study. LF1 was performed and fixed with MESH plates in 150 patients. Alternative fixation with Champy plates was used in eight patients. Three patients (2.0%) required removal of MESH plates. Seven out of 600 plates (1.2%) were removed. Reasons for removal were tenderness/pain (1), recurrent intraoral infections (1) and a nasal septum deviation correction following the LF1 (1). No statistically significant association was found with the patients' sex or age. In the literature, the reported rates of removal of titanium Champy plates range from 1.5% to 9.5% per site. This study reports a low incidence of symptomatic removal of MESH plates after Le Fort I osteotomy of 1.2% per site, which indicates an important benefit of fixation with MESH plates.

Influence of inferior border cut on lingual fracture pattern during bilateral sagittal split osteotomy with splitter and separators: A prospective observational study.

Bilateral sagittal split osteotomy (BSSO) is a widely used orthognathic surgery technique. This prospective observational study investigated the correspondence between the planned inferior border cut and the actually executed inferior border cut during BSSO. The influence of the inferior border cut on lingual fracture patterns was also analyzed. Postoperative cone beam computed tomography (CBCT) scans of 41 patients, representing 82 sagittal split osteotomies, were investigated. The inferior border cut was intended to penetrate completely through the caudal cortex. Descriptive statistics were used to analyze the executed inferior border cuts. Mixed models were used to investigate the influence of independent variables such as the surgeon's experience on the inferior border cut. Secondarily the influence of the inferior border cut on lingual fracture patterns and the incidence of bad splits was assessed. The inferior border cut reached the caudal cortex in all cases, but reached the lingual cortex in only 38% of the splits. There was no significant relationship between the inferior border cut and a specific lingual fracture line. In this study, postoperative CBCT analysis revealed that the bone cuts during BSSO were often not placed exactly as planned. No significant relationship between the inferior border cut and lingual fracture patterns or bad splits was, however, detected.

Morphological features of the mandible as predictors for neurosensory disturbances after bilateral sagittal split osteotomy.

This retrospective study aimed to identify anatomical predictors of neurosensory disturbance (NSD) after bilateral sagittal split ramus osteotomy (BSSO) by evaluating the morphology of the mandible on lateral cephalograms (LCs) and orthopantomograms (OPTs). The LCs and OPTs of 142 patients who underwent BSSO were reviewed. The influence of the mandibular angle was assessed on LCs, while the following morphological landmarks and subsequent measurements were analysed on OPTs: vertical and horizontal positions of the lingula, ramus width, mandibular body height, mandibular canal position and mandibular angle length. Post-operative NSD (hypoaesthesia) was considered permanent when objective tests or subjective evaluations indicated altered sensation one year after BSSO. Generalised linear mixed models were used to take into account the repeated measurement design (left and right measurements within one patient). Hypoaesthesia was present in 10.6% of the patients (5.6% of sites). After adjusting for age, a small mandibular body height was found to significantly increase the risk of hypoaesthesia. The other measurements showed no significant association with hypoaesthesia. These findings show a relationship between mandibular morphology and hypoaesthesia after BSSO and can aid surgeons in pre-operative assessments of the risk of NSD. Further research is needed to identify risk factors for NSD based on mandibular morphology.

Investigation of the influence of mallet and chisel techniques on the lingual fracture line and comparison with the use of splitter and separators during sagittal split osteotomy in cadaveric pig mandibles.

In bilateral sagittal split osteotomy the proximal and distal segments of the mandible are traditionally separated using chisels. Modern modifications include prying and spreading the segments with splitters. This study investigates the lingual fracture patterns and status of the nerve after sagittal split osteotomy (SSO) using the traditional chisel technique and compares these results with earlier studies using the splitter technique. Lingual fractures after SSO in cadaveric pig mandibles were analysed using a lingual split scale and split scoring system. Iatrogenic damage to the inferior alveolar nerve was assessed. Fractures started through the caudal cortex more frequently in the chisel group. This group showed more posterior lingual fractures, although this difference was not statistically significant. Nerve damage was present in three cases in the chisel group, but was not observed in the splitter group. A trend was apparent, that SSO using the chisel technique instead of the splitter technique resulted in more posterior lingual fracture lines, although this difference was not statistically significant. Both techniques resulted in reliable lingual fracture patterns. Splitting without chisels could prevent nerve damage, therefore we propose a spreading and prying technique with splitter and separators. However, caution should be exercised when extrapolating these results to the clinic.

Presence of mandibular third molars during bilateral sagittal split osteotomy increases the possibility of bad split but not the risk of other post-operative complications.

Timing of third molar removal in relation to bilateral sagittal split osteotomy (BSSO) is controversial, especially with regard to post-operative complications. We investigated the influence of mandibular third molar presence on complications after BSSO with sagittal splitters and separators, by a retrospective record review of 251 patients (502 surgical sites). Mandibular third molars were present during surgery at 169 sites and removed at least 6 months preoperatively in 333 sites. Bad splits occurred at 3.0 % (5/169) and 1.5% (5/333) of the respective sites. Presence of mandibular third molars significantly increased the risk of bad splits (OR 1.08, CI 1.02-1.13, p < 0.01). The mean incidences of permanent neurosensory disturbances, post-operative infection, and symptomatic removal of the osteosynthesis material were 5.4% (OR, 0.89; 95% CI, 0.79-1.00; p = 0.06), 8.2% (OR, 1.09; 95% CI, 0.99-1.20; p = 0.63), and 3.4% (OR, 0.97; 95% CI, .92-1.03; p = 0.35) per site, respectively, without a significant influence of mandibular third molar status. In conclusion, the presence of mandibular third molars during surgery increases the possibility of bad split but does not affect the risk of other complications. Therefore, third molars can be removed concomitantly with BSSO using sagittal splitters and separators.

Removal of bicortical screws and other osteosynthesis material that caused symptoms after bilateral sagittal split osteotomy: a retrospective study of 251 patients, and review of published papers.

Rigid fixation with either bicortical screws or miniplates is the current standard way to stabilise the mandibular segments after bilateral sagittal split osteotomy (BSSO). Both techniques are widely used and the superiority of one or other method is still debatable. One complication of rigid fixation is the need to remove the osteosynthesis material because of associated complaints. The main aim of this retrospective study was to analyse how often we needed to remove bicortical screws because they caused symptoms after BSSO in our clinic. Review of other published papers also enabled us to investigate the reported rates of removal of screws and miniplates at other centres. The mean (SD) duration of follow-up of 251 patients (502 sites) was 432 (172) days, and the number of bicortical screws removed in our clinic was 14/486 sites (3%). Other methods of fixation were used at 16 sites. We found no significant association between removal of bicortical screws and age, sex, presence of third molars, or bad splits. Published rates of removal of bicortical screws and miniplates are 3.1%-7.2% and 6.6%-22.2% per site, respectively. These findings show that fixation with bicortical screws after BSSO is associated with a low rate of removal of osteosynthesis material. Reported incidences imply a lower rate of removal for screws than for miniplates.

Bad split during bilateral sagittal split osteotomy of the mandible with separators: a retrospective study of 427 patients.

An unfavourable fracture, known as a bad split, is a common operative complication in bilateral sagittal split osteotomy (BSSO). The reported incidence ranges from 0.5 to 5.5%/site. Since 1994 we have used sagittal splitters and separators instead of chisels for BSSO in our clinic in an attempt to prevent postoperative hypoaesthesia. Theoretically an increased percentage of bad splits could be expected with this technique. In this retrospective study we aimed to find out the incidence of bad splits associated with BSSO done with splitters and separators. We also assessed the risk factors for bad splits. The study group comprised 427 consecutive patients among whom the incidence of bad splits was 2.0%/site, which is well within the reported range. The only predictive factor for a bad split was the removal of third molars at the same time as BSSO. There was no significant association between bad splits and age, sex, class of occlusion, or the experience of the surgeon. We think that doing a BSSO with splitters and separators instead of chisels does not increase the risk of a bad split, and is therefore safe with predictable results.