The effect of primary closure versus secondary closure techniques on postoperative wound pain in patients undergoing mandibular surgery: A meta-analysis.

This research is intended to explore the influence of second and first degree closure methods on the degree of wound pain and swelling of the face following the removal of the mandible. For the purpose of this study, three data sets, including PubMed and Embase, were selected. A separate statistical analysis was conducted on the choice of the trial, the collection of data and the risk of bias. Differences between trials were analysed with a chi-square approach, with data analyses dependent on I2. A sensitivity analysis was conducted, and a possible publication bias was evaluated. Ultimately, nine qualifying trials were chosen out of an original pool of 1922 related trials following an in-depth evaluation under the eligibility and exclusion criteria, as well as a follow-up screening. The results indicated that there was no statistically significant change in the degree of post-operation pain after 1 day operation between one or secondary closures of treatment (MD, -0.46; 95% CI, -0.93, 0.01, p = 0.06); the results showed that there were no statistically significant differences in post-operation wound pain after 3 days in two group (MD, -0.15; 95% CI, -0.68, 0.37, p = 0.56); the results showed that there were no statistically different effects on the post-operation wound pain after the 7th day in two groups (MD, -0.14; 95% CI, -0.31, 0.03, p = 0.1). The results showed that there were no statistically different effects on the post-operation wound pain after the 1 day in two groups (MD, -0.26; 95% CI, -0.38, -0.13, p < 0.0001); on the 3rd day after surgery, the face was significantly smaller swelling in the secondary closure of closure compared with the first-stage closure group (MD, -0.70; 95% CI, -1.40, -0.00, p = 0.05). While there is no obvious effect on post-operation wound pain in patients with mandibular surgery, there is significant difference in post-operation face swelling. The findings do not support a preference for any of these methods.

Injectate spread in ultrasound-guided inferior alveolar nerve block: a cadaveric study.

PURPOSE: Ultrasound-guided inferior alveolar nerve block (UGIANB) is a mandibular analgesic procedure in which local anesthetic is injected into the pterygomandibular space (PMS). Several studies have reported the clinical efficacy of UGIANB for mandibular surgeries; however, its effective range has never been investigated. We performed a cadaveric study to investigate the success rate of UGIANB injections and to determine whether injected dye could stain the mandibular nerve (MN) trunk and its branches. METHODS: We performed UGIANB on the bilateral faces of 4 Thiel-embalmed cadavers. A needle was advanced to the PMS under ultrasound guidance and 5 mL of dye was injected. The cadaver was dissected and inspected for the presence of dye in the PMS; the range of dye spread to any of the inferior alveolar nerve (IAN), lingual nerve (LN), buccal nerve (BN), mandibular nerve (MN), auriculotemporal nerve (ATN), or facial nerves; and for the presence of intravascular dye. RESULTS: We performed eight UGIANB procedures on four cadavers. Dye was observed in the PMS in 7/8 injections. Staining was observed in all IAN, LN, and BNs that could be identified at dissection. No MN or auriculotemporal nerves (ATNs) were stained in any injections. No intravascular dye was observed in any injections. CONCLUSIONS: UGIANB can administer anesthetic into the PMS with high accuracy. UGIANB injections reached the IAN, LN, and BNs, but did not reach the MN or ATNs located outside the PMS. The findings of this cadaveric study indicate that UGIANB can provide sufficient analgesia for mandibular surgeries.

Reasons for refusing orthognathic surgery by orthodontic patients: A cross-sectional survey.

Objective: To find out the most common reasons for refusing orthognathic surgery and to compare the responses along gender lines and in terms of open-ended and closed-ended approaches. METHODS: The cross-sectional retrospective study was conducted from August to December 2020 at the Orthodontics Department of Bahria University Medical and Dental College, Karachi, Pakistan, and comprised of patients who were planned for but refused orthognathic surgical treatment between January 2018 and July 2020. Data was collected through telephone-based interviews to record reasons of avoiding orthognathic surgery. The data-collection tool had both open-ended and closed-ended questions. Data was analysed using SPSS 23. RESULTS: Of the 60 patients, 42(70%) were females and 18(30%) were males with a mean age range of 23.25±2.19years. Overall, 19(31.7%) patients avoided surgery due to additional expense, while post-operative pain was cited as a reason by 35(58.3%) patients. Males were 9 times more concerned about their dental alignment compared to females (p=0.005). Fear of tooth injury (p<0.0001) and intra-operation and post-operation bleeding (p<0.0001) were found twice in males than females. Conclusion: The most common reasons for refusal to have orthognathic surgery were increased cost and post-operative pain. Males were more concerned about dental alignment and had higher fear of post-surgical tooth injury and intra- and post-operative bleeding compared to the females.

Ectopic third mandibular molar: evaluation of surgical practices and meta-analysis.

OBJECTIVES: To identify the preferred surgical approach (intra- or extra-oral) to remove an ectopic third mandibular molar (ETMM) according on its location and presence of an associated cyst or cutaneous fistula, and to determine the indications for a graft or osteosynthesis. MATERIALS AND METHODS: A surgical practice questionnaire was distributed to oral and maxillo-facial surgeons attending a National Congress of the French Society of Stomatology, Maxillo-facial and Oral Surgery. A systematic review of the literature and meta-analysis was carried on Pubmed, Cochrane, Embase and ScienceDirect databases using the MeSH terms: "Ectopic teeth", "Third molar", "Mandibular". One hundred and forty-three surgeons answered the questionnaire and the meta-analysis included 66 articles. RESULTS: From the questionnaire, the preferred surgical approach was intra-oral except when the ETMM was in the condyle, when it was extra-oral (69.5%; p < 0.001). In the meta-analysis, an extra-oral approach was only indicated when a cutaneous fistula was present (90% vs. 35.9%; p = 0.002), irrespective of ETMM location. In the questionnaire and meta-analysis, the presence of a cyst did not change the approach (p < 0.05). The indications for a graft or osteosynthesis were a condylar location (p < 0.001), while a cutaneous fistula decreased the indication (p = 0.04) and a cyst (p = 0.009) was only associated with a graft. CONCLUSIONS: The preferential approach was intra-oral, except when the ETMM was condylar or a cutaneous fistula was present when an extra-oral approach was preferred. Osteosynthesis or a graft were more likely when the ETMM was in the condyle. CLINICAL RELEVANCE: This study will help to orientate surgeons vis-à-vis ETMM treatment.

Analysis of condylar positioning in the temporomandibular joint following mandibular reconstruction: Introduction of a new classification system and assessment of influencing factors on displacement.

OBJECTIVE: This study investigates the unsatisfactory outcomes observed in mandibular reconstruction procedures attributed to improper condylar positioning in the Temporomandibular Joint. It also proposes a systematic classification for post-reconstruction condylar positioning dissatisfaction. METHODS: A retrospective analysis was conducted on 337 patients who underwent tumor removal and mandibular reconstruction with vascularized osteocutaneous flaps. Reconstruction techniques included conventional surgery (43.3%) and 3D technology-guided procedures (56.7%). Evaluation utilized preoperative and postoperative CT scans to assess mandibular vertical ramus length (V) and condylar alignment in both sagittal (S) and coronal (C) planes. Accordingly, a classification system for condylar positioning was developed and abbreviated as VSC. It includes four classes: Class I, proper condylar reconstruction; Class II, short ramus length; Class III, one or two aspects of sagittal/coronal condylar positions dissatisfaction; and Class IV, two or three aspects dissatisfaction. RESULTS: The overall success rate for condylar reconstruction was 85.16%. Though not statistically significant, the success rate was marginally higher in the 3D-assisted group (85.86%) compared to the conventional group (84.25%). In terms of the VSC classification, the distribution of cases across Class I, II, III, and IV were 287, 4, 9, and 37 cases, respectively. Notably, condylar dislocation was significantly associated with the defect site, particularly the body and condyle (p < 0.001, OR = 49.734, 95% CI 12.995-190.342), and the number of reconstructed segments (p = 0.025, OR = 3.480, 95% CI 1.173-10.328). CONCLUSION: The findings highlight the importance of accurate reconstruction methods and reveal implications of the defect site and the number of reconstructed segments in condylar dislocation. Consequently, we propose a classification system to refine condylar positioning assessment and enhance surgical outcomes in mandibular reconstruction.

Risk factors associated with the development of osteoradionecrosis (ORN) in Head and Neck cancer patients in Ireland: A 10-year retrospective review.

BACKGROUND AND PURPOSES: To assess osteoradionecrosis (ORN) incidence in a population of Irish Head and Neck cancer (HNC) patients, and assess precipitating factors that may contribute to ORN development to aid prevention. MATERIALS AND METHODS: Review of 1050 HNC patients attending the Dental Oncology Clinic, CUDSH between 2010 and 2021 identified 47 cases of ORN. Medical, dental and radiotherapy records of these forty-seven patients were retrospectively reviewed. Patient-, tumour-, and treatment-related variables were investigated in association with osteoradionecrosis development. Analysis conducted using SPSS, Pearson's Chi-square test (p < 0.05), and ordinal regression model. RESULTS: ORN incidence was 4.4 %. Median time from radiotherapy (RT) to ORN development was 9.5 months (range 1-98.5 months). ORN development within the mandibular surgical site was significant (p <.001), presenting at a higher Notani grade (p =.002), in mid-mandibular body region (p =.028), at radiation doses ≥ 60 Gy (p =.035), due to induced causes (p =.029), and without resolution (p =.019). CONCLUSION: This is the first retrospective study of ORN in HNC patients in Ireland over 10-year period. ORN incidence was extremely low (4.4%). As patients reported high smoking/alcohol use and poor dental attendance pre-diagnosis, this suggests intensive dental intervention pre/post-diagnosis contributed to low ORN rates. Mandibular surgery pre-RT increased risk of developing ORN at the surgical site. Therefore, we recommend future treatment planning should contour the surgical site, designating it an organ at risk (OAR), assigning a dose constraint, where oncologically possible, with emphasis on reducing the hot-spot to this region; findings reinforce importance of life-long expert dental care to reduce ORN incidence.

Effects of maxillomandibular advancement on respiratory function and facial aesthetics in obstructive sleep apnoea patients with versus without maxillomandibular deficiency.

The aim of this study was to compare the effects of maxillomandibular advancement (MMA) on respiratory function between obstructive sleep apnoea (OSA) patients with and without maxillomandibular deficiency, and to compare the changes in facial aesthetics after MMA between the two groups. MMA-treated patients who had both baseline and follow-up polysomnography (PSG) data and lateral cephalograms were enrolled in this retrospective study. In addition to PSG and cephalometric data, patient satisfaction with postoperative breathing and facial aesthetics, and overall satisfaction with the treatment were assessed. Twenty-one patients were classified as not having maxillomandibular deficiency (without-deficiency group) and 40 patients as having maxillomandibular deficiency (with-deficiency group). The improvements in respiratory parameters (e.g., apnoea-hypopnoea index) and patient satisfaction with postoperative breathing were comparable in the two groups (P = 0.094-0.713). The changes in facial profile measurements (e.g., nasal prominence, nasolabial angel, and lip positions relative to the true vertical line) and patient satisfaction with postoperative facial aesthetics were also comparable in the two groups (P = 0.148-0.983). In conclusion, no significant difference in the effects of MMA on respiratory function and facial aesthetics between OSA patients with and without maxillomandibular deficiency was observed.

Mandibular resection and defect reconstruction guided by a contour registration-based augmented reality system: A preclinical trial.

The aim of this study was to verify the feasibility and accuracy of a contour registration-based augmented reality (AR) system in jaw surgery. An AR system was developed to display the interaction between virtual planning and images of the surgical site in real time. Several trials were performed with the guidance of the AR system and the surgical guide. The postoperative cone beam CT (CBCT) data were matched with the preoperatively planned data to evaluate the accuracy of the system by comparing the deviations in distance and angle. All procedures were performed successfully. In nine model trials, distance and angular deviations for the mandible, reconstructed fibula, and fixation screws were 1.62 ± 0.38 mm, 1.86 ± 0.43 mm, 1.67 ± 0.70 mm, and 3.68 ± 0.71°, 5.48 ± 2.06°, 7.50 ± 1.39°, respectively. In twelve animal trials, results of the AR system were compared with the surgical guide. Distance deviations for the bilateral condylar outer poles were 0.93 ± 0.63 mm and 0.81 ± 0.30 mm, respectively (p = 0.68). Distance deviations for the bilateral mandibular posterior angles were 2.01 ± 2.49 mm and 2.89 ± 1.83 mm, respectively (p = 0.50). Distance and angular deviations for the mandible were 1.41 ± 0.61 mm, 1.21 ± 0.18 mm (p = 0.45), and 6.81 ± 2.21°, 6.11 ± 2.93° (p = 0.65), respectively. Distance and angular deviations for the reconstructed tibiofibular bones were 0.88 ± 0.22 mm, 0.84 ± 0.18 mm (p = 0.70), and 6.47 ± 3.03°, 6.90 ± 4.01° (p = 0.84), respectively. This study proposed a contour registration-based AR system to assist surgeons in intuitively observing the surgical plan intraoperatively. The trial results indicated that this system had similar accuracy to the surgical guide.

Segmental mandibular advancement for moderate-to-severe obstructive sleep apnoea: a pilot study.

Segmental mandibular advancement (SMA) consists of a combination of bilateral sagittal split osteotomy, anterior subapical osteotomy with extraction of the first premolars, and genioplasty, to allow an extended advancement of the mandible for the improvement of tongue base obstruction in moderate-to-severe obstructive sleep apnoea (OSA) and to minimize any unfavourable aesthetic change due to the large jaw advancement. The aim of this pilot study was to evaluate the surgical outcomes and complications following SMA in OSA patients. Twelve patients (nine male, three female) underwent SMA as part or whole of their skeletal advancement procedure for OSA. The apnoea-hypopnoea index (AHI) improved from a mean± standard deviation 42.4 ± 22.0/hour preoperatively to 9.0 ± 17.4/hour at 1 year postoperative. Surgical success (50% reduction in AHI) was achieved in 11 of the 12 patients (91.7%) at 1 year postoperative, while seven patients (58.3%) attained surgical cure (AHI<5/hour). The lowest oxygen saturation (LSAT) increased from a mean 73.3% preoperatively to 78.7% at 1 year postoperative. The airway volume increased from a mean 2.4 ± 1.7 cm3 at baseline to 6.7 ± 3.5 cm3 at 1 year postoperative (P < 0.001). No major complication occurred. This pilot study showed that SMA appears to be safe and effective as part or whole of the skeletal advancement surgery for moderate-to-severe OSA.

Is Beauty a Matter of Volume Distribution? Proposal of a New Aesthetic Three-Dimensional Guide in Orthognathic Surgery.

BACKGROUND: Orthognathic surgery is a multidisciplinary surgery in which the aesthetic results have become increasingly important, and consequently, also the predictability of the surgical outcomes. In this paper, we analyzed the volumetric distribution of the lower two-thirds of the face, in patients operated by orthognathic surgery and selected for their attractiveness. Our goal was to analyze the aesthetic volumetric distribution for gender and to propose our operating philosophy, that a normative distribution of facial volumes could be used like a new 3D aesthetic guide in orthognathic planning. METHODS: A group of 46 orthognathic patients (26 females, 20 males) with the best postoperative aesthetic score was selected by a jury of plastic surgeons, orthodontists, and journalists. The mean soft tissue volumes of the malar, maxillary, mandibular, and chin regions were analyzed. RESULTS: Overall, we measured a mean female facial volume distribution of 38.7%, 29%, 27.6%, and 4.7%, respectively, in the malar, maxillary, mandibular, and chin regions, while in males, it was 37%, 26%, 30%, and 6%, respectively. CONCLUSIONS: In this paper, the expansion of facial volumes in orthognathic surgery is proposed as a key point for facial harmonization. Beauty could be scientifically interpreted as a balanced distribution of facial volumes, and the virtual study of this distribution can become an important part of the preoperative analysis, such as a "volumetric" 3D cephalometry, where the surgeon could use average values of aesthetic volumetric distribution as preoperative surgical references.

Maxillary stability in patients with skeletal class III malocclusion treated by bimaxillary orthognathic surgery: comparison of mandible-first and maxilla-first approaches in a randomised controlled study.

The maxilla-first approach has been the standard orthognathic sequence for many years, however, with the evolution of rigid internal fixation and to eliminate any errors that could be encountered during preoperative bite registration, the mandible-first approach has become an effective treatment modality for bimaxillary orthognathic surgery. Would the maxilla-first or mandible-first orthognathic sequence in bimaxillary orthognathic surgery result in more maxillary stability in patients with skeletal class III malocclusion? Twenty-four patients with skeletal class III malocclusion were selected from the outpatient clinic of the Oral and Maxillofacial Surgery Department, Faculty of Dentistry, Cairo University. Patients were randomly divided into two equal-sized groups: the maxilla-first approach (group I), and the mandible-first approach (group II). All patients underwent cone-beam computed tomography before, immediately after (P1), and 6months after surgery (P2). Virtual planning included designing the virtual cuts and the intermediate and final splints. Both splints were three-dimensionally printed. In both approaches, hard and soft tissue landmarks were used as reference points to evaluate maxillary stability, which was calculated by subtracting P2 values from P1 values. All measures were statistically evaluated as numerical values of means and standard deviations. The differences between the radiographic measurements of the two groups were not statistically significant except for the soft tissue inclination at the nasal tip. The mandible-first approach in bimaxillary orthognathic surgery is a reliable method for achieving high maxillary stability.

Three-dimensional morphological and biomechanical analysis of temporomandibular joint in mandibular and bi-maxillary osteotomies.

Orthognathic surgery is a typical approach for treating maxillofacial deformities. However, orthognathic surgery results in positional changes in the condyles. In a previous review, the effects of orthognathic surgery on temporomandibular joints (TMJs) are not provided. Hence, in this study, we investigate the morphological changes in TMJs after mandibular and bi-maxillary osteotomies. The relationship between the morphological parameters of TMJs and symptoms of temporomandibular disorders (TMDs) is discussed. Finite element contact stress analysis is performed, and the results show that the two abovementioned surgeries can improve maxillofacial deformities, although the positions of the condyles are changed. Moreover, preoperative stress asymmetry of the left and right TMJs is observed, which remain after the surgeries. TMD patient-specific analysis shows that three joint spaces (medial joint space, lateral joint space, superior joint space) are significantly correlated with TMD symptoms.

Effect of compression on mandibular fracture haematoma-derived cells.

Mechanical stress induces a variety of biochemical and morphological reactions in bone cell biology. This study aimed to investigate appropriate pressures of osteogenesis on the biological responses of 3-dimensional cultured human mandibular fracture haematoma-derived cells by compressive loading. Six patients with mandibular fractures who underwent open reduction and internal fixation were included in the study. During the operation, fracture haematomas that formed fibrin clots were manually removed before irrigation. First, pressures were applied to human mandibular fracture haematoma-derived cell-seeded collagen sponges. The sponges were subjected to mechanical compression using loading equipment applied at no compression, 0.5, or 1 mm. Compressive loading was applied to the samples prior to compression for 0, 6, 12, or 24 hours. Collagen sponge samples were collected for quantification of mRNA using several parameters including alkaline phosphatase (ALP), osteopontin (OPN), osterix (OSX), runt-related gene 2 (RUNX2), protein level, and immunocytochemistry (anti-sclerostin). Among these the 0.5 mm compression group compared with the control and 1.0 mm compression groups upregulated mRNA expression of OPN and OSX after 24 hours. Additionally, compared with the control group, a significantly higher OSX gene expression was observed in both the 0.5 mm and 1.0 mm groups after 6, 12, and 24 hours of compression (p < 0.05). However, no significant differences were observed regarding ALP and RUNX2 expression. These results indicated increased stimulation of osteogenesis of the mandibular fracture-line gap in the 0.5 mm compression group compared with the control and 1.0 mm compression groups.

Utilization of a 3D printed dental splint for registration during electromagnetically navigated mandibular surgery.

PURPOSE: A dental splint was developed for non-invasive rigid point-based registration in electromagnetically (EM) navigated mandibular surgery. Navigational accuracies of the dental splint were compared with the common approach, that is, using screws as landmarks. METHODS: A dental splint that includes reference registration notches was 3D printed. Different sets of three points were used for rigid point-based registration on a mandibular phantom: notches on the dental splint only, screws on the mandible, contralateral screws (the side of the mandible where the sensor is not fixated) and a combination of screws on the mandible and notches on the dental splint. The accuracy of each registration method was calculated using 45 notches at one side of the mandible and expressed as the target registration error (TRE). RESULTS: Average TREs of 0.83 mm (range 0.7-1.39 mm), 1.28 mm (1.03-1.7 mm), 2.62 mm (1.91-4.0 mm), and 1.34 mm (1.30-1.39 mm) were found, respectively, for point-based registration based on the splint only, screws on the mandible, screws on the contralateral side only, and screws combined with the splint. CONCLUSION: For dentate patients, rigid point-based registration performs best utilizing a dental splint with notches. The dental splint is easy to implement in the surgical, and navigational, workflow, and the notches can be pinpointed and designated on the CT scan with high accuracy. For edentate patients, screws can be used for rigid point-based registration. However, a new design of the screws is recommended to improve the accuracy of designation on the CT scan.

Application of an open position splint integrated with a reference frame and registration markers for mandibular navigation surgery.

Navigation surgery plays an important role in modern craniomaxillofacial surgery, but it is difficult to apply navigation surgery to the mandible, due to its mobility. At present, headbands or headpins are widely used for fixation of the reference frame, and three strategies are generally used for the application of navigation surgery to the mandible. This article reports the application of a novel open position splint integrated with a reference frame and registration markers for mandibular navigation surgery as a fourth strategy. Using this custom-made integrated splint, a marker-based pair-point registration procedure was completed easily and non-invasively. Furthermore, the neurovascular canal tract could be easily identified, and the cyst, as well as the surrounding daughter cysts, could be removed with high accuracy. This strategy has potential for widespread clinical application in mandibular navigation surgery.

Describing the mandible in patients with craniofacial microsomia based on principal component analysis and thin plate spline video analysis.

Craniofacial microsomia (CFM) is most often described as a unilateral malformation of derivatives of the first and second branchial arches. The mandible has been classified using several classification systems. However, all are based on two-dimensional imaging. The aim of this study was to mathematically describe the deformed mandible based on principal component analysis (PCA) in a three-dimensional way. This may aid in defining the flaws in existing surgical corrections of the mandible through the identification of the differences in shape compared with a normal mandible in a holistic view with the help of videos. Forty-three homologous landmarks were defined to describe a mandible with CFM. Computed tomography scans of 22 patients and 30 controls were marked manually. The changes in shape between the mandibles were visualized using videos. A lateral rotation with increase in posterior rotation of the condyle due to shortening of the condyle-gonial height and a longitudinal rotation with outward bending of the mandibular angle were noted on the affected side, as well as an inward bending of the angle on the unaffected side. Due to the compensatory remodelling of the mandible on the unaffected side, one could suggest that CFM is never truly unilateral.

Correction of mandibular deviation and maxillary occlusal canting with mandibular "early" surgery and microscrews: Two case reports.

Facial asymmetry is a common complaint in patients with facial concerns. Some patients have mandibular asymmetries that have light maxillary cant compensation due to a reduced gingival exposure. A common treatment in facial asymmetries is bimaxillary surgery treatment. However, there are no cases of non-severe occlusal plane canting (OPC) with mandibular asymmetry treated with mandibular surgery and miniscrews for the extrusion of the maxillary molars. The aim of this article is to show how to correct mandibular asymmetries combined with OPC by making a single mandibular "early surgery" combined with the extrusion of the maxilla with miniscrews to correct the occlusal plane in order to avoid a Le Fort I surgery. This type of treatment provides lower medical costs, shorter surgeries, and less postoperative discomfort and invasion for patients.

Use of 3-D printing technologies in craniomaxillofacial surgery: a review.

Three-dimensional (3-D) printing is a method of manufacturing in which materials like plastic or metal are deposited onto one another in layers to produce a 3-D object. Because of the complex anatomy of craniomaxillofacial structures, full recovery of craniomaxillofacial tissues from trauma, surgeries, or congenital malformations is extremely challenging. 3-D printing of scaffolds, tissue analogs, and organs has been proposed as an exciting alternative to address some of these key challenges in craniomaxillofacial surgery. There are four broad types of 3-D printing surgical applications that can be used in craniomaxillofacial surgery: contour models (positive-space models to allow preapplication of hardware before surgery), guides (negative-space models of actual patient data to guide cutting and drilling), splints (negative-space models of virtual postoperative positions to guide final alignment), and implants (negative-space 3-D printed implantable materials or 3-D printed molds into which nonprintable materials are poured). 3-D printing technology is being successfully used for surgeries for head and neck malignancies, mandibular reconstruction, orthognathic surgeries, for mandibulectomies after osteoradionecrosis, orbital floor fracture surgeries, nasal reconstruction, and cranioplasties. The excitement behind 3-D printing continues to increase and hopefully will drive improvements in the technology and its surgical applications, especially in craniomaxillofacial region. This present review sets out to explore use of 3-D printing technologies in craniomaxillofacial surgery.

Should patients take vitamin D before mandibular operations?

Vitamin D deficiency is endemic in the United Kingdom (UK), particularly in high-risk groups. We report the outcomes of patients with low concentrations of the vitamin who had complications after reduction of mandibular fractures or osteotomy, and those who were screened preoperatively. A deficiency can be diagnosed with a simple and inexpensive blood test, and in the UK the cost of a vitamin D tablet is about £0.04/tablet/day. Patients at risk of a deficiency should be screened before mandibular operations, and those listed for orthognathic surgery or replacement of the temporomandibular joint should be asked to take a supplement before operation.

Perioral soft tissue change after isolated mandibular surgery for asymmetry patients.

INTRODUCTION: This study was intended to determine whether isolated mandibular surgery for the correction of asymmetry could also change perioral soft tissue asymmetry. PATIENTS AND METHODS: Skeletal class III patients who had undergone mandibular set-back surgery were included. The subjects were composed of two groups with (n = 20) or without (n = 30) menton (Me) deviation over 4 mm. The perioral lip landmarks were analyzed on three-dimensional image from cone-beam computed tomography taken before and 6 months after the operation. The bilateral and inter-group differences and pre- and post-operative changes were statistically analyzed. RESULTS: The corner of mouth on the deviated side was 1.9 mm shorter vertically than that on the contralateral side in patients with asymmetry. After mandibular surgery, the deviated Me moved 5.5 mm to the contralateral side and the lip canting was corrected by 2.4° in the asymmetry group. The degree of Me deviation was significantly correlated with the degree of midline asymmetry in perioral soft tissue landmarks including subnasale, upper and lower lip midline. The predictor variable that affected the changes in lip cant was the surgical correction of Me deviation. DISCUSSION: The correction of chin deviation by isolated mandibular surgery could significantly improve the subnasal and lip asymmetry.