Stability of intraoral vertical ramus osteotomies for mandibular setback: a longitudinal study

This study aimed to investigate the postoperative longitudinal skeletal changes and stability following intraoral vertical ramus osteotomies (IVRO) for orthognathic mandibular setback, and the possible risk factors that might affect the stability. A retrospective cohort study was conducted. Lateral cephalograms were analyzed for the predictor (magnitude of setback and adjunctive procedures) and outcome (stability of vertical and horizontal dimensions) variables at six time points. A total of 152 patients (mean age 24.2 years) were included in the study. Following IVRO, the mandible measured at B-point had moved a mean 0.50 mm posteriorly at 1 week after the removal of intermaxillary fixation (7 weeks postoperative); this was followed by progressive small anterior relapse. At 2 years postoperative, the mean relapse of the mandible after IVRO measured at B-point was 0.05 mm (standard deviation 1.14 mm), representing 0.7% of the mean surgical movement. Large setback (>8 mm) showed significantly higher relapse compared to small setback (<4 mm) at 2 years after surgery (P = 0.021). Patients who underwent adjunctive mandibular surgeries other than IVRO showed no significant differences in relapse compared to those who underwent IVRO alone. In conclusion, IVRO for mandibular setback is a stable procedure in the long term, with small relapse of 0.05 mm after 2 years.     

The virtual human face: Superimposing the simultaneously captured 3D photorealistic skin surface of the face on the untextured skin image of the CBCT scan

The aim of this study was to evaluate the impact of simultaneous capture of the three-dimensional (3D) surface of the face and cone beam computed tomography (CBCT) scan of the skull on the accuracy of their registration and superimposition. 3D facial images were acquired in 14 patients using the Di3d (Dimensional Imaging, UK) imaging system and i-CAT CBCT scanner. One stereophotogrammetry image was captured at the same time as the CBCT and another 1 h later. The two stereophotographs were individually superimposed over the CBCT using VRmesh. Seven patches were isolated on the final merged surfaces. For the whole face and each individual patch: maximum and minimum range of deviation between surfaces; absolute average distance between surfaces; and standard deviation for the 90th percentile of the distance errors were calculated. The superimposition errors of the whole face for both captures revealed statistically significant differences (P = 0.00081). The absolute average distances in both separate and simultaneous captures were 0.47 and 0.27 mm, respectively. The level of superimposition accuracy in patches from separate captures was 0.3–0.9 mm, while that of simultaneous captures was 0.4 mm. Simultaneous capture of Di3d and CBCT images significantly improved the accuracy of superimposition of these image modalities.     

The reliability of cone-beam computed tomography (CBCT) – Generated frontal cephalograms

BackgroundThe purpose of this study was to evaluate the reliability of measurements from cone-beam computed tomography (CBCT)-generated frontal cephalogram.Materials and methodsCBCT and conventional posteroanterior (PA) cephalograms were taken from 30 adult patients. CBCT image was set according to the Frankfurt-Horizontal (FH) plane as the horizontal plane and the midsagittal reference (MSR) plane. The CBCT frontal cephalograms were generated using the orthogonal Raycast method (group CT_raycast), the orthogonal maximum intensity projection (MIP) method (group CT_MIP) after the head reorientation according to the reference planes, and the generator tool provided by the employed 3-dimensional (3D) imaging software (group CT_generator), respectively. The differences between the CBCT-generated frontal cephalograms and conventional PA cephalograms (group PA_ceph) were compared by paired t-test (p < 0.05).ResultsThe significant differences were shown in two measurements for group CT_raycast, in 12 measurements for group CT_MIP, and in eight measurements for group CT_generator. It was confirmed that the CBCT frontal cephalograms, generated by means of the Raycast method (Group CT_raycast), were more comparable to the conventional PA cephalograms in their measurements than were the others (Groups CT_MIP, CT_generator).ConclusionThis study may well suggest that frontal cephalograms derived by 3D CBCT reorientation can be effectively employed in clinical applications.     

Comparative study of cephalometric measurements using 3 imaging modalities

Background

The authors conducted a study to compare 2-dimensional (2D) lateral cephalometric radiography (LCR), 2D cone-beam computer tomographic (CBCT)–generated cephalogram and 3-dimensional (3D) CBCT for assessing cephalometric measurements.

Displacement comparison of CAD–CAM titanium and zirconia abutments to implants with different conical connections

Purpose

To compare the displacements of CAD–CAM zirconia and titanium abutments into different internal connection systems after torquing.

Upper airway morphologic changes after mandibular setback surgery in skeletal class III malocclusion patients measured using cone beam computed tomography superimposition

This study used the superimposition of cone beam computed tomography (CBCT) images to evaluate three-dimensional morphologic changes in the upper airway space of skeletal class III malocclusion patients with normally positioned maxilla who had undergone mandibular setback surgery.The upper airways of 18 subjects (10 males and eight females) who underwent mandibular setback surgery were assessed using CBCT superimposition at T0 (2 weeks before surgery) and T1 (1 year after surgery) according to the cervical vertebrae 1 (CV1), CV2, CV3 and CV4 reference planes on CBCT.The cross-sectional area and anteroposterior width (APW) in the CV1 and CV2 planes had significantly decreased at 1 year after surgery. The largest decrease was observed in the oropharynx area. However, the APW/transverse width in the CV2 plane had increased at 1 year after surgery.These findings suggest that mandibular setback surgery can cause a reduction in the upper airway space; physiologic deformation of the oropharynx occurs after mandibular setback surgery.     

The accuracy of three-dimensional prediction planning for the surgical correction of facial deformities using Maxilim

The motivation for orthognathic surgery is to improve facial appearance and quality of life. This study aimed to validate a three-dimensional (3D) orthognathic planning programme (Maxilim) for predicting soft tissue changes following Le Fort I advancements. Cone beam computed tomography (CBCT) scans were taken before surgery (T₁) and at 6–12 months after surgery (T₂) for 13 patients. For each patient the 3D hard tissue changes between T₁ and T₂ were determined by CBCT superimposition on the cranial vault. Using Maxilim, each patient's skeletal movements were used to generate a 3D soft tissue prediction. The actual soft tissue mesh at T₂ was compared to the predicted mesh. The face was divided into areas: nose, right and left nares, right and left paranasal regions, upper and lower lip, and chin. The absolute distance between meshes for each region was calculated. A one-sample t-test showed the distances between the meshes for all of the areas were within 3 mm (P < 0.05), except for the upper lip which was greater than 3 mm (P = 0.577). Using Maxilim, 3D soft tissue predictions for Le Fort I advancements were clinically satisfactory in the regions assessed, but associated with marked errors around the region of the upper lip.     

Bleeding during and after dental extractions in patients with liver cirrhosis

Little is known about the prevention and management of acquired coagulopathies, such as those affecting cirrhotic patients. The objective of this analytic retrospective observational study was to evaluate patients on the liver transplant waiting list according to the following outcomes: (1) presence of unusual intraoperative bleeding (>10 min after routine haemostatic procedures); and (2) presence of postoperative haemorrhagic complications. The outcomes were analysed according to clinical and laboratory variables. A total of 190 visits were performed for extraction of 333 teeth (ranging from 1 to 9 teeth per visit), with platelet count ranging from 16,000 to 216,000 and international normalized ratio (INR) below 3. Twelve cases (6.31%) had unusual intraoperative bleeding and 12 had postoperative haemorrhagic complications. All the events were controlled by local measures. Intraoperative bleeding was associated with low count of platelets (P = 0.026). However, this counting could explain only 16% (adjusted R² = 0.16) of the cases of bleeding (P = 0.44), meaning that platelet function changes might be involved. Our results show that cirrhotic patients presenting platelet count above 16,000 and INR below 3 need no previous blood transfusion, with local measures being enough to manage haemorrhagic events.     

Tumor PD-L1 expression is associated with improved survival and lower recurrence risk in young women with oral cavity squamous cell carcinoma

Young patients with oral cavity squamous cell carcinoma (OCSCC) are often recognized as a distinct epidemiological cohort. In this study, genomic and immune-based metrics were correlated with long-term outcomes for a young patient population treated at a single institution. A fully clinically annotated, retrospective cohort of 81 patients aged ≤45 years with OCSCC is described, and the impact of clinicopathological features on long-term survival outcomes is reported. Genomic and immune parameters were integrated utilizing a whole-exome sequencing and immunohistochemical approach among females in the cohort. It was found that young OCSCC patients had favorable outcomes (10-year disease-free survival 79.1%, overall survival 80.0%) regardless of sex, particularly if they presented with oral tongue primaries and early stage disease. While mutational analysis appeared similar to that of older patients with OCSCC who lack a smoking history, a comparatively high degree of PD-L1 expression and PD-1/L1 concordance (P = 0.001) was found among young female OCSCC patients. Subjects with greater membranous PD-L1 positivity and the presence of tumor-infiltrating lymphocytes had a decreased risk of recurrence (P = 0.01 and P = 0.01, respectively) and improved survival (P = 0.04 and P = 0.03, respectively). These findings warrant further validation and support the investigation of immunotherapeutic approaches targeting PD-1/L1 interactions in young OCSCC patients.     

Three-dimensional analysis of nasolabial soft tissue changes after Le Fort I osteotomy: a systematic review of the literature

A systematic review was conducted to investigate the three-dimensional (3D) effect of Le Fort I osteotomy on the nasolabial soft tissues. The literature search was conducted using the MEDLINE (accessed via PubMed), Embase, and Cochrane electronic databases until January 2018. A total of 333 studies were identified (PubMed, n = 292; Embase, n = 41; Cochrane Library, n = 0). Seventeen met the inclusion criteria. The studies were essentially retrospective. The risk of bias was considered high in 15 studies, medium in one study, and low in one study. 3D soft tissue analysis was performed at least 6 months after surgery (mean 8.3 months). The main image acquisition technique reported was cone beam computed tomography (CBCT), associated or not with 3D photography. Approximately 50% of the studies performed two-jaw surgery, 25% performed maxillary surgery only, and the other 25% included heterogeneous intervention groups. The most reported nasolabial changes were anterior and lateral movements of the nasomaxillary soft tissues and upper lip, together with anterior and superior movement of the nasal tip. The alar cinch suture and V–Y closure technique seemed to have little effect in counteracting the undesirable postoperative nasolabial changes. CBCT superimposition presented a reliable 3D assessment for simultaneous measurement of skeletal and soft tissue changes.     

Intraoperative factors associated with free flap failure in the head and neck region: a four-year retrospective study of 216 patients and review of the literature

The aim of this study was to identify intraoperative factors associated with free flap failure. The outcomes of 216 patients (220 flaps) were analyzed retrospectively. A statistical analysis was performed to determine the association of flap failure with the intraoperative factors of prolonged operation time, flap type, vascular pedicle at the recipient site, and use of vasoactive medication. A review of the recent literature was also conducted to identify other intraoperative risk factors. Univariate regression analysis revealed that a prolonged operative time (P = 0.013) and the vascular pedicle at the recipient site (P = 0.027) were primary risk factors for flap failure. Furthermore, the intraoperative use of papaverine improved the success rate of free flap transfer (P = 0.015). Multivariate regression analysis showed that only the application of papaverine remained statistically significant (P = 0.011). The results confirmed that the choice of flap type had no influence on free flap survival (P = 0.583). In addition, the literature review showed that excessive intraoperative fluid administration is a risk factor for free flap failure. These conclusions may provide microvascular surgeons with information to reduce the failure rate. Also, microvascular surgeons should always consider the details of intraoperative fluid management.     

Accuracy of various impression materials and methods for two implant systems: An effect size study

Purpose

An accurate impression is required for implant treatment. The aim of this in-vitro study was to determine the effect size of the impression material/method, implant system and implant angulation on impression transfer precision.

Direct percutaneous puncture digital-subtraction-angiography-based classification and treatment selection for soft-tissue arteriovenous malformations of maxillofacial region: a retrospective study

Treatment of arteriovenous malformations (AVMs) should be individualized based on the imaging findings. A total of 117 AVM cases were categorized into three types based on the angio-architectural characteristics: Type I (n = 14, no draining vein or diameter of the draining vein <2 mm); Type II (n = 64, draining vein diameter 2–6 mm); and Type III (n = 39, draining vein diameter >6 mm). Subjects were randomly allocated to one of two treatment groups: Group A (n = 59) received multipoint percutaneous ethanol injection (MPEI), while Group B (n = 58) received super-selective angiograms followed by embolization with gelfoam (EFAG) plus MPEI. Patients were followed up for 2–6 years. A significant between-group difference with respect to treatment outcomes was observed only for Type III cases (P < 0.05). Direct percutaneous puncture digital-subtraction-angiography-guided classification of AVMs provides easy-to-follow guidelines for its clinical management. EFAG plus MPEI with reduced procedure time and the amount of ethanol should be used for Type III AVMs.     

Three-dimensional surface models of the facial soft tissues acquired with a low-cost scanner

Although there has been an increase in three-dimensional (3D) scanning methods available on the market, they are generally expensive. The DI3D system is considered a good scanner for the acquisition of soft tissue surface images. The Microsoft Kinect scanner is a much more affordable alternative for acquiring 3D models. The aim of this study was to determine whether the precision and accuracy of Kinect are similar to those of DI3D. To verify the accuracy, 10 patients were scanned with both methods The models of each patient acquired from the two scanners were superimposed using a surface-to-surface registration technique, and the distances between the models were recorded for 10 different anatomical regions of interest. For the evaluation of precision, one patient was scanned 11 different times with the Kinect scanner, and these models were compared using the same superimposition method. It was found that the average difference between the two methods was 0.3 ± 2.03 mm. The assessment of reproducibility showed an average difference between the images taken with Kinect of 0.1 ± 0.6 mm (P < 0.05, one-sample t-test). Thus, Kinect showed good precision and reasonable accuracy, and appears to be an interesting and promising resource for facial analysis.     

Canal transportation caused by one single-file and two multiple-file rotary systems: A comparative study using cone-beam computed tomography

Aim

This ex-vivo study aimed to compare canal transportation in mesio-buccal canal of mandibular first molars prepared with Mtwo and Revo-S multi-file and Neoniti single-file nickel–titanium (Ni–Ti) rotary systems using cone-beam computed tomography (CBCT).

Impact of resveratrol on bone repair in rats exposed to cigarette smoke inhalation: histomorphometric and bone-related gene expression analysis

This study investigated the effect of resveratrol on bone healing and its influence on the gene expression of bone-related markers in rats exposed to cigarette smoke. Two calvarial defects were created in each of 60 rats, which were assigned equally (n = 20) to three groups: (1) resveratrol (10 mg/kg) + smoke exposure (SMK + RESV); (2) placebo + smoke exposure (SMK + PLA); or (3) placebo + no smoke exposure (NS + PLA). Substances were administered daily for 30 days following surgery. Smoke inhalation was started 7 days before surgery and continued for 30 days after surgery. One defect was processed for histomorphometric analysis and the other was used for mRNA quantification of bone-related gene expression by qPCR. The remaining defect was smaller in the SMK + RESV (2.27 ± 0.61 mm, P = 0.0003) and NS + PLA (2.17 ± 0.74 mm, P = 0.0005) groups than in the SMK + PLA group (3.12 ± 0.47 mm). Higher levels of Runx2 were observed in the NS + PLA group than in the smoke exposure groups (vs. SMK + PLA, P = 0002; vs. SMK + RESV, P = 0.052); levels of Lrp-5 were also higher in the no smoke exposure group (vs. SMK + RESV, P = 0.009; vs. SMK + PLA, P = 0.003). Resveratrol therapy decreased RANKL/OPG expression when compared to placebo (SMK + RESV vs. SMK + PLA, P = 0.017). Dkk1 levels were decreased in the SMK + RESV group when compared to the SMK + PLA (P = 0.006) and NS + PLA groups (P = 0.005). In conclusion, resveratrol optimizes the repair of critical-sized bone defects, up-regulating the gene expression of important bone remodelling markers in rats exposed to cigarette smoke inhalation.     

Comparison of rim-sparing versus rim-removal techniques in deep lateral wall orbital decompression for Graves’ orbitopathy

The aim of this study was to compare the surgical outcomes of deep lateral orbital decompression using the rim-sparing technique versus the rim-removal technique in Graves’ orbitopathy (GO). A retrospective cohort study of 75 orbits in 50 patients with GO was performed. Proptosis, best corrected visual acuity (BCVA), intraocular pressure (IOP), upper and lower lid margin to reflex distances (MRD-1 and MRD-2, respectively), diplopia, ocular restriction, and GO quality of life (GO-QOL) questionnaire results were analyzed pre- and postoperatively. The average proptosis reduction ranged from 3.5 mm to 6.7 mm with the rim-sparing technique and from 3.6 mm to 6.7 mm with the rim-removal technique (P > 0.05). All orbits with dysthyroid optic neuropathy in the rim-sparing group and 87.5% of such orbits in the rim-removal group showed improved BCVA (P = 0.321). Reductions in IOP, MRD-1, and MRD-2 were observed with both techniques. Patients in the rim-sparing group had greater improvements in GO-QOL appearance score (P = 0.043). In conclusion, rim-sparing orbital decompression provides efficacious outcomes with greater improvements in patient quality of life than the rim-removal technique. The rim-sparing technique should be considered as a preferable option because it preserves the integrity of the lateral vertical maxillary buttress and bony protection for the orbital contents.     

Genetic and epigenetic alterations in the tumour,tumour margins,and normal buccal mucosa of patients with oral cancer

Despite adequate surgical resection, oral squamous cell carcinoma (OSCC) shows a high rate of recurrence and metastasis, which could be explained by the presence of molecular alterations in seemingly normal tumour margins and the entire oral mucosa. The aims of this study were (1) to assess the presence of gene amplification (c-Myc and HER2) and promoter methylation (p14 and p16) in the tumours, tumour margins, and unaffected oral mucosa of 40 OSCC patients, and (2) to evaluate the possibility of using these alterations as prognostic markers. c-Myc and HER2 genes were quantified by means of real-time PCR (qPCR), and p14 and p16 methylation status was determined by methylation-specific PCR (MSP PCR). All tissues examined exhibited molecular alterations in various proportions. Tumour tissues, as expected, showed the highest prevalence of alterations, while oral mucosa showed the lowest. Multiple alterations (co-alterations) in tumours and tumour margins were significantly more frequent than in unaffected oral mucosa (P < 0.001 and P = 0.027, respectively). HER2 amplification in margin tissue (P < 0.001) and swabs (P = 0.013), as well as the existence of three co-alterations in margins (P = 0.001) and macroscopically unaffected oral mucosa (P < 0.001) were correlated with shorter disease-specific survival.