The precision of drill calibration for dynamic navigation.

OBJECTIVES: To quantify the reproducibility of the drill calibration process in dynamic navigation guided placement of dental implants and to identify the human factors that could affect the precision of this process in order to improve the overall implant placement accuracy. METHODS: A set of six drills and four implants were calibrated by three operators following the standard calibration process of NaviDent® (ClaroNav Inc.). The reproducibility of the position of each tip of a drill or implant was calculated in relation to the pre-planned implants' entry and apex positions. Intra- and inter-operator reliabilities were reported. The effects of the drill length and shape on the reproducibility of the calibration process were also investigated. The outcome measures for reproducibility were expressed in terms of variability range, average and maximum deviations from the mean distance. RESULTS: A satisfactory inter-rater reproducibility was noted. The precision of the calibration of the tip position in terms of variability range was between 0.3 and 3.7 mm. We noted a tendency towards a higher precision of the calibration process with longer drills. More calibration errors were observed when calibrating long zygomatic implants with non-locking adapters than with pointed drills. Flexible long-pointed drills had low calibration precision that was comparable to the non-flexible short-pointed drills. CONCLUSION: The clinicians should be aware of the calibration error associated with the dynamic navigation placement of dental and zygomatic implants. This should be taken in consideration especially for long implants, short drills, and long drills that have some degree of flexibility. CLINICAL SIGNIFICANCE: Dynamic navigation procedures are associated with an inherent drill calibration error. The manual stability during the calibration process is crucial in minimising this error. In addition, the clinician must never ignore the prescribed accuracy checking procedures after each calibration process.

The Accuracy of Intraoral Registration for Dynamic Surgical Navigation in the Edentulous Maxilla.

PURPOSE: Despite the high clinical accuracy of dynamic navigation, inherent sources of error exist. The purpose of this study was to improve the accuracy of dynamic navigated surgical procedures in the edentulous maxilla by identifying the optimal configuration of intra-oral points that results in the lowest possible registration error for direct clinical implementation. MATERIALS AND METHODS: Six different 4-area configurations were tested by 3 operators against positive and negative controls (8-areas and 3-areas, respectively) using a skull model. The two dynamic navigation systems (X-Guide® and NaviDent®) and the two registration methods (bone surface tracing and fiducial markers) produced four registration groups. The accuracy of the registration was checked at the frontal process of the zygoma. Intra- and inter- operator reliability for each registration group were reported. Multiple comparisons were conducted to find the best configuration with the minimum registration error. RESULTS: Ranking revealed one configuration in the tracing groups (Conf.3) and two configurations in the fiducial groups (Conf.3 and Conf.5) that had the best accuracy. When the inferior surfaces of the zygomatic buttress were excluded, fiducial registration produced better accuracy with both systems (p 0.006 and <0.0001). However, tracing 1 cm areas at these surfaces bilaterally resulted in similar registration accuracy as placing fiducial markers there (p 0.430 and 0.237). NaviDent® performed generally better (p 0.049, 0.001 and 0.002) albeit having a wider margin of uncertainty in the obtained values. Changing the distribution of the 4 tracing areas or fiducial markers had a less pronounced effect with X-Guide® than with the NaviDent® system. CONCLUSION: For edentulous maxillary surgeries, 4 fiducial markers placed according to configuration 3 or 5 result in the lowest registration error. Where implants are being placed bilaterally, an additional 2 sites may reduce the error further. For bilateral zygomatic implant placement, it is optimal to place 2 fiducials on the inferior surfaces of the maxillary tuberosities, other 2 on their buccal surfaces, and 2 on the anterior labial surface of the alveolar bone. Utilising the inferior zygomatic buttress is recommended over the inferior maxillary tuberosities in other types of maxillary surgeries.

Improvement in facial aesthetics of orthognathic patients after surgery-first approach.

Facial appearance significantly affects psychosocial wellbeing, and an improvement in facial aesthetics is considered an essential outcome of orthognathic treatment. The surgery-first approach (SFA) has emerged as a promising alternative to the conventional orthodontics-first approach (OFA) due to its potential advantages in reducing treatment duration and cost, delivering early aesthetic improvement, and increasing patient satisfaction. However, its impact on final facial aesthetics and how it compares with the OFA has, to our knowledge, not yet been investigated. This retrospective study aimed to compare the improvement in facial aesthetics after orthognathic surgery in an SFA and an OFA group. Preoperative and postoperative 3-dimensional stereophotogrammetry facial images of 40 patients were evaluated by five professional assessors using the Global Aesthetic Improvement Scale (GAIS). Similar aesthetic improvement outcomes were found in both the SFA and OFA groups. The GAIS score significantly correlated with the following facial variables: upper lip projection, chin prominence, facial proportions, paranasal hollowing, lip competence, mandibular projection, and facial profile. No significant correlation was found between a change in aesthetic score and the surgical variables. There was a positive association between overall GAIS score and the gender and experience level of the individual assessors. This study suggests that aesthetic facial improvement achieved with the SFA is satisfactory and comparable to that of the OFA.

Surgery-first approach for correction of class III dentofacial deformity with Le Fort I osteotomy; is it advantageous?

The surgery-first approach (SFA) to orthognathic treatment aims to reduce its duration without compromising the outcome. However, the objective assessment of the achieved occlusion has been limited. This study was designed to assess the treatment duration, outpatient appointment number, and quality of occlusal outcomes for two groups of patients; one treated with the SFA and the other with an orthodontics-first approach (OFA). We carried our a retrospective cohort study of case records for twenty consecutive SFA, and 23 consecutive OFA, cases with class III malocclusions, treated with Le Fort I maxillary osteotomy only. Pre-and post-treatment study models were assessed using the Peer Assessment Rating (PAR). Significant differences (p<0.001) were found between the median active treatment durations (10.2 months for the SFA and 32.5 months for the OFA) and appointment numbers (14 for SFA and 24 for OFA). Median absolute PAR reductions were 40 for the SFA and 39 for the OFA. There was no significant difference between the groups regarding quality of occlusal correction. Treatment durations for the SFA group were significantly shorter than for the OFA group, with fewer outpatient appointments. The quality of occlusal outcome for both SFA and OFA groups were satisfactory and comparable.

Orthognathic patient perception of 3D facial soft tissue prediction planning.

The primary aim of this study was to explore patients' perceptions regarding the impact of 3D prediction planning (3D PP) of facial soft tissue changes following orthognathic surgery. The study was carried out on 30 patients who were shown photorealistic 3D soft tissue prediction planning before undergoing orthognathic surgery to demonstrate the expected facial changes. Distraction osteogenesis and cleft deformities were excluded from the study before consenting to surgery. Following surgery, the included patients were asked to complete a standard questionnaire to explore their perceptions regarding the impact, accuracy, and value of 3D prediction planning. The majority of the 30 participants perceived 3D PP to be beneficial in reducing their presurgical anxiety, increasing their motivation to undergo surgery, improving the accuracy of their surgical expectations, and enhancing doctor-patient communication. Most of the patients perceived their surgical soft tissue changes to be better than the predictions. Significant positive correlations were detected between satisfaction with the delivered service and the facility of seeing 3D PP (rs = 0.4; p = 0.034). Similarly, 3D PP improved patients' confidence in the surgical decision (rs = 0.4; p = 0.031), as well as increasing their motivation to undergo surgery (rs = 0.5; p = 0.010). 3D PP was found to be effective in improving the quality of orthognathic surgical care.

A novel surgical model for the preclinical assessment of the osseointegration of dental implants: a surgical protocol and pilot study results.

BACKGROUND: Dental implants are considered the gold standard replacement for missing natural teeth. The successful clinical performance of dental implants is due to their ability to osseointegrate with the surrounding bone. Most dental implants are manufactured from Titanium and it alloys. Titanium does however have some shortcomings so alternative materials are frequently being investigated. Effective preclinical studies are essential to transfer the innovations from the benchtop to the patients. Many preclinical studies are carried out in the extra-oral bones of small animal models to assess the osseointegration of the newly developed materials. This does not simulate the oral environment where the dental implants are subjected to several factors that influence osseointegration; therefore, they can have limited clinical value. AIM: This study aimed to develop an appropriate in-vivo model for dental implant research that mimic the clinical setting. The study evaluated the applicability of the new model and investigated the impact of the surgical procedure on animal welfare. MATERIALS AND METHODS: The model was developed in male New Zealand white rabbits. The implants were inserted in the extraction sockets of the secondary incisors in the maxilla. The model allows a split-mouth comparative analysis. The implants' osseointegration was assessed clinically, radiographically using micro-computed tomography (µ-CT), and histologically. A randomised, controlled split-mouth design was conducted in 6 rabbits. A total of twelve implants were inserted. In each rabbit, two implants; one experimental implant on one side, and one control implant on the other side were applied. Screw-shaped implants were used with a length of 8 mm and a diameter of 2 mm. RESULTS: All the rabbits tolerated the surgical procedure well. The osseointegration was confirmed clinically, histologically and radiographically. Quantitative assessment of bone volume and mineral density was measured in the peri-implant bone tissues. The findings suggest that the new preclinical model is excellent, facilitating a comprehensive evaluation of osseointegration of dental implants in translational research pertaining to the human application. CONCLUSION: The presented model proved to be safe, reproducible and required basic surgical skills to perform.

Psychology input to an orthognathic clinic: Patients' perception of service quality.

AIMS: The aim of this study was to assess patient satisfaction with a clinical psychology service, integrated within an inter-disciplinary orthognathic planning clinic. METHOD: A self-report, custom-designed questionnaire was sent to patients who had completed orthognathic treatment within the last three years. Of the 60 patients approached, 49 responded. RESULTS: The great majority of patients agreed that there was a need for a psychological assessment and that its purpose was adequately explained. Most patients were happy with the information given during their appointment and found the experience helpful. A number of patients felt that additional appointments would have been helpful shortly before, and after, surgery. CONCLUSIONS: The group of orthognathic patients studied found the pre-treatment psychology assessment, provided for them through the combined clinic, to be very acceptable and beneficial. Some suggested that further appointments, throughout the treatment journey, as well as supportive literature, might also have been helpful.

Engineered Coatings for Titanium Implants To Present Ultralow Doses of BMP-7.

The ongoing research to improve the clinical outcome of titanium implants has resulted in the implemetation of multiple approches to deliver osteogenic growth factors accelerating and sustaining osseointegration. Here we show the presentation of human bone morphogenetic protein 7 (BMP-7) adsorbed to titanium discs coated with poly(ethyl acrylate) (PEA). We have previously shown that PEA promotes fibronectin organization into nanonetworks exposing integrin- and growth-factor-binding domains, allowing a synergistic interaction at the integrin/growth factor receptor level. Here, titanium discs were coated with PEA and fibronectin and then decorated with ng/mL doses of BMP-7. Human mesenchymal stem cells were used to investigate cellular responses on these functionalized microenvironments. Cell adhesion, proliferation, and mineralization, as well as osteogenic markers expression (osteopontin and osteocalcin) revealed the ability of the system to be more potent in osteodifferentiation of the mesenchymal cells than combinations of titanium and BMP-7 in absence of PEA coatings. This work represents a novel strategy to improve the biological activity of titanium implants with BMP-7.

Multi-view stereophotogrammetry for post-mastectomy breast reconstruction.

A multi-view three-dimensional stereophotogrammetry system was developed to capture 3D shape of breasts for breast cancer patients. The patients had received immediate unilateral breast reconstruction after mastectomy by the extended latissimus dorsi flap and without contralateral surgery. In order to capture the whole breast shape including the inframammary fold, the patients were introduced to the imaging room and leaned over the imaging rig to open up the inframammary fold and to expose the entire area of each breast. The imaging system consisted of eight high-resolution ([Formula: see text] pixels) digital cameras and four flash units. The cameras were arranged in four stereo pairs from four different view angles to cover the whole surface of the breasts. The system calibration was carried out ahead of every capture session, and the stereo images were matched to generate four range images to be integrated using an elastic model proposed. A watertight breast mesh model was reconstructed to measure the volume of the breast captured. The accuracy of using the developed multi-view stereophotogrammetry system for breast volume measurement was 11.12cc with SEM 7.74cc, comparing to the measurements of the water displacement method. It was concluded that the 3D stereophotogrammetry image system developed was more reliable than the method of water displacement.

Radiological assessment of bioengineered bone in a muscle flap for the reconstruction of critical-size mandibular defect.

This study presents a comprehensive radiographic evaluation of bone regeneration within a pedicled muscle flap for the reconstruction of critical size mandibular defect. The surgical defect (20 mm × 15 mm) was created in the mandible of ten experimental rabbits. The masseter muscle was adapted to fill the surgical defect, a combination of calcium sulphate/hydroxyapatite cement (CERAMENT™ |SPINE SUPPORT), BMP-7 and rabbit mesenchymal stromal cells (rMSCs) was injected inside the muscle tissue. Radiographic assessment was carried out on the day of surgery and at 4, 8, and 12 weeks postoperatively. At 12 weeks, the animals were sacrificed and cone beam computerized tomography (CBCT) scanning and micro-computed tomography (µ-CT) were carried out. Clinically, a clear layer of bone tissue was identified closely adherent to the border of the surgical defect. Sporadic radio-opaque areas within the surgical defect were detected radiographically. In comparison with the opposite non operated control side, the estimated quantitative scoring of the radio-opacity was 46.6% ± 15, the mean volume of the radio-opaque areas was 63.4% ± 20. Areas of a bone density higher than that of the mandibular bone (+35% ± 25%) were detected at the borders of the surgical defect. The micro-CT analysis revealed thinner trabeculae of the regenerated bone with a more condensed trabecular pattern than the surrounding native bone. These findings suggest a rapid deposition rate of the mineralised tissue and an active remodelling process of the newly regenerated bone within the muscle flap. The novel surgical model of this study has potential clinical application; the assessment of bone regeneration using the presented radiolographic protocol is descriptive and comprehensive. The findings of this research confirm the remarkable potential of local muscle flaps as local bioreactors to induce bone formation for reconstruction of maxillofacial bony defects.

How accurate are rapid prototyped (RP) final orthognathic surgical wafers? A pilot study.

Computer packages have been introduced to simulate the movements of the jaw in three dimensions to facilitate planning of treatment. After final 3-dimensional virtual planning, a rapid prototype wafer can be manufactured and used in theatre. Our aim was to assess the accuracy of rapid prototyping of virtual wafers derived from laser scanned dental models using CAD/CAM software. Upper and lower plaster models from 10 orthognathic patients, the articulated models, and the conventional wafers were scanned. The virtual wafers were made from CAD/CAM software, and printed on a stereolithographic printer. We also scanned the articulated models with rapid prototype wafers in place. The validity of the final rapid prototype wafer was measured by the accuracy with which upper and lower models related to one another. The absolute mean error of the rapid prototype wafer when aligned with the dental models was 0.94 (0.09) mm. The absolute distance of the 2 models articulated by conventional and rapid prototype wafers ranged from 0.04 - 1.73mm. The rapid prototype wafers were able to orientate the upper and lower dental models with an absolute mean error of 0.94 (0.09) mm, but it ranged from 0.04-1.73mm.

Evaluation of an interactive multi-media device for delivering information on Le Fort I osteotomy.

This study was carried out on volunteers to evaluate a newly developed interactive software package aimed at informing prospective Le Fort I osteotomy patients regarding the surgical technique and possible complications. The aim of the study was to compare two methods of information delivery; a multi-media tablet device delivering both graphic and verbal information, and an audio device delivering essentially the same information in verbal form only. The null hypothesis was that there would be no difference between the efficiencies of the two methods. The subjects' ability to recall the information delivered by both devices was assessed using a questionnaire. The tablet device participants scored an average of 15.48 points, while the audio device participants scored an average of 268 points. The difference was statistically significant (p < 0.001), suggesting that the multi-media tablet device was more effective method.

Three-dimensional assessment of facial appearance following surgical repair of unilateral cleft lip and palate.

BACKGROUND AND OBJECTIVE: Objective assessment of postsurgical facial asymmetry can be difficult, but three-dimensional (3D) imaging techniques have made this possible. The objective of this study was to assess residual asymmetry in surgically repaired unilateral cleft lip (UCL) and unilateral cleft lip and palate (UCLP) patients and to compare this with noncleft controls. DESIGN: Retrospective multicohort comparative study. PATIENTS AND METHODS: Fifty-one 10-year-old children with surgically managed UCLP and 44 children with UCL were compared with a control group of 68 ten-year-olds. The 3D facial models at rest and with maximum smile were created using a 3D imaging system. Asymmetry scores were produced using both anatomical landmarks and a novel method of facial curve analysis. RESULTS: Asymmetry for the whole face was significantly higher in both cleft groups compared with controls (P < .001). UCLP asymmetry was higher than UCL (P < .001). In cleft patients, the upper lip and nasal rim were the most asymmetric (P < .001 to .05). Control subjects also displayed a degree of facial asymmetry. Maximum smile did not significantly affect the symmetry of the whole face, but it increased asymmetry of the vermillion border and nasal rim in all three groups (P < .001). CONCLUSIONS: Despite surgical intervention at an early age, asymmetry remains significant in cleft patients at 10 years of age. Three-dimensional imaging is a noninvasive objective assessment tool that identifies specific areas of the face responsible for asymmetry. Facial curve analysis describes the face more comprehensively and characterizes soft tissue contours.

Clinical significance of creative 3D-image fusion across multimodalities [PET+CT+MR] based on characteristic coregistration.

OBJECTIVE: To investigate a registration approach for 2-dimension (2D) based on characteristic localization to achieve 3-dimension (3D) fusion from images of PET, CT and MR one by one. METHOD: A cubic oriented scheme of"9-point & 3-plane" for co-registration design was verified to be geometrically practical. After acquisiting DICOM data of PET/CT/MR (directed by radiotracer 18F-FDG etc.), through 3D reconstruction and virtual dissection, human internal feature points were sorted to combine with preselected external feature points for matching process. By following the procedure of feature extraction and image mapping, "picking points to form planes" and "picking planes for segmentation" were executed. Eventually, image fusion was implemented at real-time workstation mimics based on auto-fuse techniques so called "information exchange" and "signal overlay". RESULT: The 2D and 3D images fused across modalities of [CT+MR], [PET+MR], [PET+CT] and [PET+CT+MR] were tested on data of patients suffered from tumors. Complementary 2D/3D images simultaneously presenting metabolic activities and anatomic structures were created with detectable-rate of 70%, 56%, 54% (or 98%) and 44% with no significant difference for each in statistics. CONCLUSION: Currently, based on the condition that there is no complete hybrid detector integrated of triple-module [PET+CT+MR] internationally, this sort of multiple modality fusion is doubtlessly an essential complement for the existing function of single modality imaging.

An assessment of the quality of care provided to orthognathic surgery patients through a multidisciplinary clinic.

The quality of care delivered to 74 patients undergoing orthognathic surgery was assessed using a patient satisfaction questionnaire and data collected from hospital case records. Surgical complications, hospital services, patient satisfaction, and impact on quality of life, were the main aspects considered. The majority of patients reported that their treatment objectives had been achieved and that they were satisfied with the quality of care provided. The main concern of the patients regarding the clinic was the waiting time before an appointment could be offered. Eating and breathing difficulties and low mood after surgery were the main reported complications. Sixty-three patients experienced post-operative weight loss. The importance of a nutritious, high calorie soft diet should be emphasised and the use of menthol inhalations following maxillary osteotomies should be considered more frequently. Clinicians should be aware of post-operative low mood, which may require psychological support. We developed a sensitive assessment battery with comprehensive parameters to audit quality of orthognathic surgery service, and recommend that a similar approach should be considered by teams which undertake management of orthognathic patients.

Three-dimensional image fusion across PET+MRI modalities based on the approach of characteristic coregistration.

BACKGROUND AND AIMS: Because there is no complete three-dimensional (3D) hybrid detector integrated PET+MRI internationally, this study aims to investigate a registration approach for a two-dimensional (2D) hybrid based on characteristic localization to achieve a 3D fusion from the images of PET and MRI as a whole. METHODS: A cubic-oriented scheme of "9-point and 3-plane" for a coregistration design was verified to be geometrically practical. Through 3D reconstruction and virtual dissection, human internal feature points were sorted to combine with preselected external feature points for matching process. By following the procedure of feature extraction and image mapping, the processes of "picking points to form planes" and "picking planes for segmentation" were executed. Eventually, the image fusion was implemented at the real-time workstation Mimics based on auto-fuse techniques called "information exchange" and "signal overlay". RESULTS: A complementary 3D image across PET+MRI modalities, which simultaneously present metabolic activities and anatomic structures, was created with a detectable rate of 56%. This is equivalent to the detectable rate of PET+CT or MRI+CT with no statistically significant difference, and it facilitates a 3D vision that is not yet functional for 2D hybrid imaging. CONCLUSIONS: This cross-modality fusion is doubtless an essential complement for the existing toolkit of a 2D hybrid device. Thus, it would potentially improve the efficiency of diagnosis and therapy for oncology.

An overview of three-dimensional imaging in dentistry.

UNLABELLED: This paper reviews the role of three-dimensional digital imaging in dentistry and its related specialties. Current methods of image capture of the dentition are described, along with the current status of CAD/CAM-based restorative treatment. The advantages of cone beam computed tomography (CBCT) in comparison with conventional radiography are outlined in the fields of endodontics, periodontology, oral surgery and orthodontics. The integration of CBCT with state-of-the-art computer planning systems for implantology is described. The application of multi-modal imaging techniques in the management of orthognathic and cleft lip and palate patients is explained and potential future educational benefits are considered. CLINICAL RELEVANCE: With three-dimensional digital imaging and its related technologies advancing rapidly, it is important for both general and specialist dental practitioners to have an awareness of its current and potential future roles in clinical practice.

Factors Contributing to the Spread of Odontogenic Infections: A prospective pilot study.

OBJECTIVES: Spreading odontogenic infections (SOI) are the commonest type of serious infections encountered in the orofacial region. A prospective multi-centre study was conducted in the West of Scotland to investigate the contributing role of social, systemic and microbial factors in the pathogenesis of SOI. METHODS: Twenty-five patients with severe odontogenic infections were recruited over a period of six months. At admission, clinical assessment included temperature rise, haematological and biochemical investigations. Demographic data, social and past medical histories were obtained. Microbiology samples were collected to identify causative microorganisms and the clinical management of each infection was recorded. RESULTS: Most infections were associated with teeth or roots. Eighty percent of the patients were tobacco smokers and 72% came from deprived areas. Five patients were intravenous drug users, four admitted chronic alcohol abuse, six had underlying systemic disorders and two were at high risk of malnutrition. A raised C-reactive protein at admission was a useful indicator of the severity of infection. Inappropriate prior antibiotic treatment in the absence of surgical drainage was common. Microbiology results showed a predominance of strict anaerobes, notably anaerobic streptococci, Prevotella and Fusobacterium species. CONCLUSION: SOIs remain surprisingly common and our present pilot study showed a particular association with social deprivation and tobacco smoking. Further elucidation of the role of malnutrition in SOI would be of interest. Molecular characterisation of the microflora associated with SOI may help to highlight whether bacterial factors play a role in converting a localised dentoalveolar abscess into a serious, spreading odontogenic infection.

Face bow and articulator for planning orthognathic surgery: 1 face bow.

Orthognathic surgery that involves movement of the maxilla relative to the skull is usually planned using casts mounted on an articulator. Accurate positioning of the maxilla relative to the skull is essential for reliable planning, but current methods of mounting casts on articulators are inaccurate and unreliable. We propose that the casts should be mounted using the relation between the horizontal plane and the resting head position to define the position of the skull. A photographic study of 10 subjects confirmed the reproducibility of the head position and its relation to the horizontal plane. A face bow incorporating a circular spirit level was used to transfer the relation between the horizontal and the maxillary dentition to a semiadjustable articulator. The angle between the horizontal and maxillary occlusal planes was measured from six lateral cephalograms and compared with those of casts mounted on a semiadjustable articulator using a face bow with either an orbital pointer or a spirit level. The face bow with a spirit level produced considerably more accurate results.