Definition of New Three-Dimensional Cephalometric Analysis of Maxillomandibular Sagittal Relationship for Orthodontics and Orthognathic Surgery: Normative Data Based on 700 CBCT Scans.

The objective of the study was to define the norm of new 3-dimensional cephalometric analysis of maxillomandibular sagittal relationship with the patient in Natural Head Position. A cross-sectional study was performed using 700 consecutives cone beam computed tomography datasets of pre-orthodontic patients received for three-dimensional craniofacial analysis. To stablish the clinical norm of the new sagittal reference (linear distance A-B), the correlation with the gold standard (ANB angle) was estimated with the Pearson's correlation coefficient. Subsequently, the prognostic values of the linear distance A-B was calculated to define the clinical norm. The sample was composed by 463 women (66.1%) and 237 men (33.9%). The mean age was 30 ± 14,5 years old (range 6-71 y old). According to the skeletal class classification (ANB), 46.1% (323) were class I, 42% (294) class II, and 11.9% (83) class III. The regression model found that each additional grade of the ANB angle imply a mean increase of 1.24 mm of the distance A-B ( P <0.001). The normative value of the linear distance A-B was obtained through the prognostic values of the distance for the limits of the ANB norm 0 to 4. These values were on the range of 0.52 to 5.48 mm. Therefore, the clinical norm for cephalometric maxillomandibular sagittal relationship using linear distance from point A-B is: 3±2.48 mm. With this new approach, we can define the skeletal sagittal relationship of the patient in natural head position overcoming the limitations of using intracranial or occlusal plane references improving the diagnosis and orthognathic surgical planning process.

Factors Affecting Implant Failure and Marginal Bone Loss of Implants Placed by Post-Graduate Students: A 1-Year Prospective Cohort Study.

STATEMENT OF THE PROBLEM: Most of the clinical documentation of implant success and survival published in the literature have been issued by either experienced teams from university settings involving strict patient selection criteria or from seasoned private practitioners. By contrast, studies focusing on implants placed and rehabilitated by inexperienced post-graduate students are scarce. PURPOSE: To record failure rates and identify the contributing factors to implant failure and marginal bone loss (MBL) of implants placed and rehabilitated by inexperienced post-graduate students at the one-year follow-up. MATERIAL AND METHODS: A prospective cohort study was conducted on study participants scheduled for implant therapy at the International University of Catalonia. An experienced mentor determined the treatment plan in accordance with the need of each participant who signed an informed consent. All surgeries and prosthetic rehabilitation were performed by the post-graduate students. Implant failure rate, contributors to implant failure, and MBL were investigated among 24 variables related to patient health, local site, and implant and prosthetic characteristics. The risk of implant failure was analyzed with a simple binary logistic regression model with generalized equation equations (GEE) models, obtaining unadjusted odds ratios (OR). The relationship between MBL and the other independent variables was studied by simple linear regression estimated with GEE models and the Wald chi2 test. RESULTS: One hundred and thirty dental implants have been placed and rehabilitated by post-graduate students. Five implants failed before loading and none after restoration delivery; survival and success rates were 96.15% and 94.62%, respectively. None of the investigated variables significantly affected the implant survival rate. At the one-year follow-up, the mean (SD) MBL was 0.53 (0.39) mm. The following independent variables significantly affected the MBL: Diabetes, implant depth placement. The width of keratinized tissue (KT) and probing depth (PD) above 3 mm were found to be good indicators of MBL, with each additional mm of probing depth resulting in 0.11 mm more MBL. CONCLUSION: The survival and success rates of dental implants placed and rehabilitated by inexperienced post-graduate students at the one-year follow-up were high. No contributing factor was identified regarding implant failure. However, several factors significantly affected MBL: Diabetes, implant depth placement, PD, and width of KT. CLINICAL IMPLICATIONS: Survival and success rates of dental implants placed and rehabilitated by inexperienced post-graduate students were high at the one-year follow-up, similar to experienced practitioners. No contributing factors were identified regarding implant failure; however, several factors significantly affected MBL: Diabetes, implant depth placement, PD, and KM.

Rehabilitation of the severely atrophic maxilla using LeFort I maxillary advancement and simultaneous zygoma implant placement: Proof of concept.

PURPOSE: To illustrate the workflow for simultaneous LeFort I maxillary advancement and zygomatic implant (ZI) placement. MATERIALS AND METHODS: Three consecutive patients referred for the rehabilitation of the severely atrophic maxilla were treated with simultaneous LeFort I maxillary advancement and ZI placement. An evaluation of the treatment protocol was carried out to validate the proposed workflow: indications, treatment planning, surgical splint manufacturing, surgical procedure and prosthetic loading. RESULTS: Maxillary reposition was carried out according to the previous virtual planning. Consequently, in all cases extrasinusal or sinus slot paths were used, proper emergence of the implant platform fully surrounded by alveolar bone was ensured, and full-arch rehabilitation supported by ZI was performed. A straight facial profile was achieved postoperatively in all cases and no surgical complications were noted. No resorption of maxillary distal bone was evident at the end of the first year of follow-up. However, a mean relapse of -4.3 mm (-10.06%) was evidenced for maxillary downward movement, and conversely, an extra-forward maxillary movement was observed (mean +1.4 mm, +82.8%) in all cases. CONCLUSIONS: Besides restoring oral function and aesthetics, this technique avoids donor site morbidity, decreases surgical time, and shortens the overall rehabilitation period.

Semi-Automated Three-Dimensional Condylar Reconstruction.

The objective was to validate a semi-automated segmentation method for 3-dimensional (3D) reconstruction of the mandibular condyle from cone beam computed tomography (CBCT) data and illustrate its application in volumetric analysis of the condyle.Ten CBCT datasets were used to validate the proposed semi-automatic method for 3D rendering of mandibular condyles. First, a standardized orientation protocol of the skull was applied. After defining the volume of interest, a grey-scale cut-off value was selected to allow an automatic reconstruction of the condyle's surface. Subsequently, condylar contour was optimized manually. The whole process was repeated twice by 2 independent investigators. Volumetric measurements of the condyle were used as a measure of conformity between both investigators. The reproducibility of condylar volume reconstruction was excellent for intra-examiner measurements (CV = 3.65%, intraclass correlation coefficient = 0.97) and good for inter-examiner measurements (CV = 7.15%, ICC = 0.89). The overall mean time required for the segmentation process was 6.31 + 2.78 minutes. The proposed protocol provides an accurate and reproducible tool for 3D reconstruction of the mandibular condyle using CBCT data. Its implementation will enable adequate follow-up of morphological changes in bone tissue with a Hounsfield unit-based imaging segmentation method.

Cranial Base Superimposition of Cone-Beam Computed Tomography Images: A Voxel-Based Protocol Validation.

OBJECTIVES: The primary objective of the present study was to find the gold-standard accuracy of voxel-based superimposition of cone-beam computed tomography (CBCT) datasets with a protocol developed for the Dolphin Imaging 3D software. The secondary objectives were to analyze reproducibility and efficiency of this protocol. STUDY DESIGN: Twenty-five CBCT datasets of patients with dental implants present were selected. Each Base Volume dataset was duplicated to create a second volume. Subsequently, both volumes were superimposed with a voxel-based protocol consisting of 3 successive steps "Side-by-side Superimposition"; "Overlay Superimposition"; and "Export Orientation to 2nd Volume". The protocol's accuracy was evaluated by measuring the mean distance between the apex of each dental implant on the Base Volume and second volume datasets. Efficiency was given by the mean time needed to complete all superimposition steps. Reproducibility was analyzed by calculating the intraclass correlation coefficients. RESULTS: Mean time needed to complete the protocol was 198 seconds. The protocol had a rotational accuracy of 0.10° to 019° and a translational accuracy of 0.20 to 0.24 mm. Intra-observer and inter-observer reproducibility were 1 and 0.921 to 1, respectively. CONCLUSIONS: The protocol is accurate, precise, reproducible, and efficient. The validation of this method enables unbiased analysis of surgical outcomes based on a single, user-friendly software product that is widely available in academic and clinical settings.

Opciones de tratamiento. Presentación del caso / Treatment option. Case presentation

Se presenta un caso clínico de un paciente adulto de 24 años con clase III esquelética y dentaria, mordida cruzada posterior izquierda, resalte invertido, gran apiñamiento superior e inferior y línea media superior desviada hacia la derecha (AU)

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Opciones de tratamiento. Así fue tratado / Treatment option. How was treated

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