Validity and reproducibility of cephalometric measurements obtained from digital photographs of analogue headfilms

The emerging market of digital cephalographs and computerized cephalometry is overwhelming the need to examine the advantages and drawbacks of manual cephalometry, meanwhile, small offices continue to benefit from the economic efficacy and ease of use of analogue cephalograms. The use of modern cephalometric software requires import of digital cephalograms or digital capture of analogue data: scanning and digital photography. The validity of digital photographs of analogue headfilms rather than original headfilms in clinical practice has not been well established. Digital photography could be a fast and inexpensive method of digital capture of analogue cephalograms for use in digital cephalometry. AIM: The objective of this study was to determine the validity and reproducibility of measurements obtained from digital photographs of analogue headfilms in lateral cephalometry. MATERIAL AND METHODS: Analogue cephalometric radiographs were performed on 15 human dry skulls. Each of them was traced on acetate paper and photographed three times independently. Acetate tracings and digital photographs were digitized and analyzed in cephalometric software. Linear regression model, paired t-test intergroup analysis and coefficient of repeatability were used to assess validity and reproducibility for 63 angular, linear and derivative measurements. RESULTS AND CONCLUSIONS: 54 out of 63 measurements were determined to have clinically acceptable reproducibility in the acetate tracing group as well as 46 out of 63 in the digital photography group. The worst reproducibility was determined for measurements dependent on landmarks of incisors and poorly defined outlines, majority of them being angular measurements. Validity was acceptable for all measurements, and although statistically significant differences between methods existed for as many as 15 parameters, they appeared to be clinically insignificant being smaller than 1 unit of measurement. Validity was acceptable for 59 of 63 measurements obtained from digital photographs, substantiating the use of digital photography for headfilm capture and computer-aided cephalometric analysis.publishersversionPeer reviewe

Comparing the accuracy and precision of digital model transfer methods used in virtual orthognathic planning

Objectives: The hard and soft tissues of the head and neck, dentition, and temporomandibular joint are the determining elements in orthognathic surgery planning. The accuracy and precision of the relationship between the jaws at the beginning of treatment and their final position depend on an accurate dentition record. The aim of this study was to determine the simplest and most feasible virtual dental model transfer method for three-dimensional orthognathic planning according to clinical applicability, technical difficulty, effective costs, accuracy, and precision. Material and Methods: A total of ten spherical porcelain markers were placed in plaster models of the maxilla and mandible of a patient. The models were scanned using an intraoral optical scanner, an extraoral digital model scanner, and cone-beam computerized tomography. To evaluate reliability, each measurement was repeated 10 times at 1-week intervals and the distances between points were measured horizontally and vertically. The findings obtained in the study were evaluated statistically using IBM SPSS Statistics 2.2 program. Results: Measurements obtained with the extraoral model scanner did not differ from the digital caliper method (P > 0.05), while there were significant differences between the digital caliper and the other methods (intraoral 3D scanner P = 0.000; CBCT P = 0.001). Conclusion: Although all of the measurements showed high consistency among all methods, the most accurate results were obtained with the extraoral digital model scanner. (r = 0.99, P = 0.01, P < 0.05)

Dental implant placement with inferior alveolar nerve repositioning in severely resorbed mandibles: a retrospective multicenter study of implant success and survival rates, and lower lip sensory disturbances

Abstract Background The purpose of this study was to analyze medium-to-long-term implant success and survival rates, and lower lip sensory disturbance after placement of dental implants with simultaneous inferior alveolar nerve (IAN) repositioning. Methods Fifteen patients (3 men, 12 women) treated in two centers were included in this retrospective study. The ages of the participants ranged from 19 to 68. A total of 48 dental implants were placed in 23 posterior mandibular segments simultaneously with IAN transposition or lateralization. The residual bone above the IAN ranged from 0.5 to 7.0 mm. Crestal bone changes were measured using cone beam computed tomography (CBCT) images. Disturbance of the IAN was evaluated subjectively using a modified questionnaire. Results The healing process was uneventful in fourteen patients. In one patient, spontaneous fracture of the operated mandible occurred on tenth day after the surgery. The implant in the fracture line was removed at the time of open reduction and fixation. One more implant was lost after 5 years of loading. Therefore, the overall dental implant survival rate was 95.8%, whereas all implants in function were judged as successful after a follow-up period of 1 to 10 years. Transient neurosensory disturbances (ND) were observed in all patients who underwent IAN lateralization and IAN transposition. At follow-up times of 3 years, 5 years, and 10 years, weak hypoesthesia remained in two subjects treated with IAN transposition. None of the patients developed neuropathic pain after the procedure. Conclusions Within the limitations of this study, we conclude that reconstruction of severely resorbed mandibles with dental implants in conjunction with IAN repositioning is an effective and reliable technique. Although neurosensory disturbances are the most common complication after surgery, they tend to resolve over time. Advanced surgical skills are required to perform this technique

Bioceramics in Orthognathic Surgery

The aim of this study was to investigate the volumetric stability of particulated hydroxyapatite and biphasic ceramic in the sites of osteotomy after orthognathic surgery and subperiostally placed during contourplasty

Volumetric Analysis of Implanted Biphasic Calcium Phosphate/Collagen Composite by Three-Dimensional Cone Beam Computed Tomography Head Model Superimposition

Facial onlay augmentation is often performed as an ancillary procedure simultaneously with orthognathic surgery to improve facial appearance, with hydroxyapatite (HAp) and HAp-based composites often used as the materials of choice. The ability to apply HAp in a granular rather than solid shape form may be responsible for its comparatively reduced rate of complications. However, a known complication of HAp and HAp composites is reduction of implant volume over time associated with resorption of the material. Evaluation of the volumetric changes of implanted biphasic calcium phosphate (HAp/b-TCP)/collagen composite in the malar areas from baseline to 4 months, 9e12 months, and 18e24 months after surgery using cone beam computed tomography (CBCT) surface superimposition and volumetric subtraction was done. The average decrease of volume of implanted HAp/b-TCP 4 months after surgery was 18.6%. Further volumetric decreases were negligible and a mean total volume loss of 21.65% was found at 18e24 months postoperatively

Digital platform for planning facial asymmetry orthodontic-surgical treatment preparation

ABSTRACT Dentofacial deformities usually are surgically treated, and 3D virtual planning has been used to favor accurate outcomes. Cases reported in the present article show that orthognathic surgery carried out to correct facial asymmetries does not comprise only one treatment protocol. 3D virtual planning might be used for surgical planning, but it should also be used to diagnose the deformity, thus allowing for an analysis of the best-recommended possibilities for the orthodontic preparation that suits each individual case

Digital platform for planning facial asymmetry orthodontic-surgical treatment preparation

<div><p>ABSTRACT Dentofacial deformities usually are surgically treated, and 3D virtual planning has been used to favor accurate outcomes. Cases reported in the present article show that orthognathic surgery carried out to correct facial asymmetries does not comprise only one treatment protocol. 3D virtual planning might be used for surgical planning, but it should also be used to diagnose the deformity, thus allowing for an analysis of the best-recommended possibilities for the orthodontic preparation that suits each individual case.</p></div

Predictability of orthodontic tooth movement with aligners: effect of treatment design

Abstract Backgrounds The present study was designed to define: (1) which are the less predictable OTM with Invisalign aligners when the treatment plan is designed by expert operators, (2) if the presence and shape of attachments influence the predictability of OTM and (3) if patients’ demographics influence OTM predictability. The sample comprises 79 prospectively recruited patients (mean age 30.8 years; SD 12.0; 23 M, 56 F), treated by expert operators with an average of 27 aligners (SD 15) in the maxillary arch and 25 aligners (SD 11) in the mandibular arch. Post-treatment digital models and final virtual treatment plan models were exported from ClinCheck® software as STL files and subsequently imported into Geomagic Qualify ®software, to compare final teeth positions. The differences were calculated and tested for statistical significance for each tooth in the mesial–distal, vestibular–lingual and occlusal–gingival directions, as well as for angulation, inclination and rotation. In addition, the statistical significance of categorical variables was tested. Results The lack of correction was significant for all movements and in all group of teeth (P < 0.01) except for the rotation of maxillary first molar. The prescribed OTM, the group of teeth and movement, the frequency of aligner change and the use of attachment influence the outcome. The greatest discrepancies in predicted and achieved tooth position were found for angular movements and rotation of teeth characterized by round-shaped crowns, for a ratio of approximately 0.4° per 1° prescribed. Optimized attachments for upper canines and lower premolar rotation seem not working properly. Second molar movements are mostly unexpressed. Furthermore, changing the aligner every 14 days will reduce the lack of correction of the 12% with respect to 7 days aligner change. Conclusions Predictability of orthodontic movement with aligners still has limitations related to the biomechanics of the system: the shape of some attachments and the characteristics of aligner material need to be redefined. However, the results of this study allow to properly design the virtual treatment plan, revealing how much overcorrection is needed and which attachments are most effective