Three-dimensional dento-skeletal effects of mandibular midline distraction and surgically assisted rapid maxillary expansion: A retrospective study.

It was the aim of the study to provide a three-dimensional evaluation of dento-skeletal effects following bone-borne vs tooth-borne mandibular midline distraction (MMD) and tooth-borne surgically assisted rapid maxillary expansion (SARME). A retrospective observational study was conducted. Cone beam computed tomography (CBCT) records were taken pre-operatively (T1), immediately post-distraction (T2) and 1 year post-operatively (T3). All included 30 patients had undergone MMD (20 bone-borne MMD; 10 tooth-borne MMD). A total of 20 bone-borne MMD and 8 tooth-borne MMD patients had simultaneously undergone tooth-borne SARME. At T1 vs T3, canine (p = 0.007; 26.0 ± 2.09 vs 29.2 ± 2.02) and first premolar (p = 0.005; 33.8 ± 2.70 vs 37.0 ± 2.43) showed significant expansion on the tip level for tooth-borne MMD. This was no significant on the apex level, indicating tipping. Bone-borne MMD showed a parallel distraction gap, whereas tooth-borne MMD showed a V-shape. There was a significant (p = 0.017; 138 ± 17.8 vs 141 ± 18.2) inter-condylar axes increase for bone-borne MMD. In conclusion, bone-borne vs tooth-borne MMD and tooth-borne SARME showed stable dento-skeletal effects at 1 year post-operatively. Bone-borne and tooth-borne MMD seemed not to be superior to each other. The choice of distractor type therefore depends more on anatomical and comfort factors.

Current Practice for Transverse Mandibular and Maxillary Discrepancies in the Netherlands: A Web-Based Survey Among Orthodontists and Oral and Maxillofacial Surgeons.

The main objective of this study was to provide an overview of the current practice for transverse mandibular and maxillary discrepancies in the Netherlands using a web-based survey. Orthodontists (ORTHO) and Oral and Maxillofacial Surgeons (OMFS) in the Netherlands were invited to the web-based survey via their professional association. Three cases were presented which could be treated non-surgically and surgically. Participants were asked what treatment they preferred: no treatment, orthodontic treatment with optional extractions or surgically assisted orthodontic treatment. The web-based survey ended with questions on various technical aspects and any experienced complication. Invitation was sent to all 303 members of professional association for ORTHO and to all 379 members of professional association for OMFS. Overall response number was 276 (response rate of 40.5%), including 127 incomplete responses. Generally, ORTHO prefer orthodontic treatment with optional extractions and OMFS lean towards surgically assisted orthodontic treatment. Mandibular Midline Distraction appears to be less preferred, possibly due to lack of clinical experience or knowledge by both professions despite being proven clinical stable surgical technique with stable long-term outcomes. There seems to be consensus on technical aspects by both professions, however, there are various thoughts on duration of consolidation period. Complications are mostly minor and manageable.

Patient experience and satisfaction of surgically assisted rapid maxillary expansion and mandibular midline distraction.

Little is known regarding patient experience and satisfaction with surgically assisted rapid maxillary expansion (SARME) and mandibular midline distraction (MMD). This study therefore aimed to assess patient experience and satisfaction with these techniques in two different groups. The first group answered the post-surgical patient satisfaction questionnaire on a 7-point Likert scale during a long-term follow-up recall. The second group answered a visual analogue scale questionnaire (range: 0-10) with different questions regarding experience and satisfaction, at different time points during the first year of treatment. In both groups, 17 patients were included. Regarding the post-surgical patient satisfaction questionnaire, a mean satisfaction rate of 6.4 (range: 4-7) was reported, with a mean follow-up of 6.5 years post-operatively. In the visual analogue scale group, the mean satisfaction rate was 8.0 and did not significantly differ from the expectations pre-operative (P = 0.96). Both procedures showed relatively low pain scores, although a significant higher score was observed in MMD post-operatively (P = 0.00051). Regarding hindrance, the scores were moderate; the bone-borne distractor in the mandible gained higher scores than the tooth-borne distractor in the mandible. In conclusion, both SARME and MMD gain high satisfaction rates.

How accurate is the soft tissue prediction of Dolphin Imaging for orthognathic surgery?

PURPOSE: The purpose of this retrospective study is to evaluate the accuracy of soft tissue prediction models with Dolphin Imaging. MATERIALS AND METHODS: Preoperative and 1-year postoperative Lateral cephalograms (LCG) of patients undergoing Le Fort I, bilateral sagittal split osteotomy (BSSO) or bimaxillary osteotomy (Bimax) between 2006 and 2009 were retrospectively collected. A hard tissue virtual surgery was performed on the preoperative LCG to match the hard tissue of the 1-year postoperative LCG. The soft tissue changes were then modelled by Dolphin Imaging (version 11.5b) and the differences in x- and y-coordinates of 11 hard tissue and 14 soft tissue landmarks between the predicted model and 1-year postoperative LCG were determined. Statistical analyses were performed using a one-tailed, one-sample t-test for both soft- and hard tissue differences, and a Bland-Altman plot for interobserver bias. RESULTS: A total of 108 patients were included, the mean age was 30 years and 23% were male. The virtual treatment was considered accurate; all hard tissue landmark differences were less than 1mm. The soft tissue model by Dolphin Imaging showed significant differences of more than 2mm for several landmarks, including the vertical positioning of Stomion Inferius (P=0.007), Lower lip (P=0.005) and Pogonion (P=0.03) in the Bimax group and horizontal positioning of Stomion Inferius (P<0.001) in the BSSO group. CONCLUSIONS: Dolphin Imaging gives reasonable predictions of postoperative outcome. There is, however, room for improvement, especially regarding the vertical prediction in the lower lip region.

Three-dimensional evaluation of mandibular midline distraction: A systematic review.

OBJECTIVE: To provide a literature overview on mandibular midline distraction (MMD) using three-dimensional (3D) imaging analysis techniques. Regarding different distractor types, the focus was on changes in position and/or morphology of the mandibular condyle and temporomandibular joint (TMJ), skeletal effects, dental effects, soft tissue effects, and biomechanical and masticatory effects, specifically on the mandible and TMJ. METHODS: Studies up to March 27 2017 were included, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines, using Embase, Medline OvidSP, Web-of-science, Scopus, Cochrane, and Google Scholar. RESULTS: Thirty-one full-text papers were assessed for eligibility and 15 met the inclusion criteria: prospective (2), retrospective (2), case-report (1) and computational analysis (10). All included studies were graded low (level 4-5) for quality of evidence, using the Oxford Centre for Evidence-Based Medicine criteria. CONCLUSION: There is a limited number of studies available, with low levels of evidence and small sample sizes. Bone-borne distraction seems preferable when taking skeletal effects into account. Tooth-borne distraction leads to significant dental tipping. Hybrid distractors combined with parasymphyseal step osteotomy seem to be the most stable under functional masticatory loads. The effects of chewing appeared to be marginal during the latency period. No permanent TMJ symptoms were reported, and little is known about soft tissue effects. SYSTEMATIC REVIEW REGISTRATION: International Prospective Register of Systematic Reviews, PROSPERO CRD42014010010.

Automated human skull landmarking with 2D Gabor wavelets.

Landmarking of CT scans is an important step in the alignment of skulls that is key in surgery planning, pre-/post-surgery comparisons, and morphometric studies. We present a novel method for automatically locating anatomical landmarks on the surface of cone beam CT-based image models of human skulls using 2D Gabor wavelets and ensemble learning. The algorithm is validated via human inter- and intra-rater comparisons on a set of 39 scans and a skull superimposition experiment with an established surgery planning software (Maxilim). Automatic landmarking results in an accuracy of 1-2 mm for a subset of landmarks around the nose area as compared to a gold standard derived from human raters. These landmarks are located in eye sockets and lower jaw, which is competitive with or surpasses inter-rater variability. The well-performing landmark subsets allow for the automation of skull superimposition in clinical applications. Our approach delivers accurate results, has modest training requirements (training set size of 30-40 items) and is generic, so that landmark sets can be easily expanded or modified to accommodate shifting landmark interests, which are important requirements for the landmarking of larger cohorts.

Complications in Mandibular Midline Distraction.

Mandibular midline distraction (MMD) is a relatively new surgical technique for correction of transverse discrepancies of the mandible. This study assesses the amount and burden of complications in MMD. A retrospective cohort study was performed on patients who underwent MMD between 2002 and 2014. Patients with congenital deformities or a history of radiation therapy in the area of interest were excluded. Patient records were obtained and individually assessed for any complications. Complications were graded using the Clavien-Dindo classification system (CDS). Seventy-three patients were included of which 33 were males and 40 were females. The mean follow-up was 2.1 years. Twenty-nine patients had minor complications, grades I and II. Two patients had a grade IIIa and three patients had a grade IIIb complication. Common complications were pressure ulcers, dehiscence, and (transient) sensory disturbances of the mental nerve. This study shows that although MMD is a relatively safe method, complications can occur. Mostly the complications are mild, transient, and manageable without the need for any reoperation.