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A protocol for qualitatively reviewing the accuracy of fabricated implant surgical guides is presented. Once these guides have been inserted and fixed intraorally, cone beam computed tomography (CBCT) scans are made. Implant positions can be recalculated by processing the series of sleeve images on the CBCT scans. This protocol offers an opportunity for double-checking the accuracy of a fabricated guide before surgery in certain circumstances.

Statement of problem Patients diagnosed with a cleft palate often have a congenitally missing maxillary lateral incisor. The congenital cleft presents the practitioner with challenges including the quantity and quality of bone, a surgically managed cleft correction, and limited clinical space. Purpose The purpose of the present prospective investigation was to report preliminary results at the 1-year follow-up for this planned 5-year investigation of narrow diameter implants used to restore a missing lateral incisor in patients with a cleft palate. Material and methods Fourteen study participants with a cleft palate and a missing maxillary lateral incisor were enrolled based on established criteria. Narrow diameter implants (AstraTech OsseoSpeed TX 3.0S and 3.5 mm) were placed by using a 2-stage protocol and restored. All study participants received an Atlantis abutment and a cement-retained crown. Four probing depth measurements and bleeding on probing were measured at baseline and at 1 year. Probing depth measurements were evaluated using a 2-way repeated measures ANOVA with Tukey-Kramer multiple comparisons tests. Radiographic marginal bone loss was measured at 1-year by using a digital subtraction technique and evaluated by using a repeated measures ANOVA. Pretreatment cone beam computed tomography (CBCT) images were used to measure a mean gray level that was proportional to bone mineral density (BMD) in the implant site. One-way mixed ANOVA was used to compare the mean gray level and average implant stability quotient (ISQ) loading. A Pearson correlation was also tested between those parameters (α=.05) for each statistical analysis. Results The mean marginal bone loss at 1 year was 0.601 ±0.48 mm. Regarding probing depth measurements, a 2-way repeated measures ANOVA found both the location (P=.012) and time (P=.009) were significant. The Tukey-Kramer multiple comparisons test showed a significant difference between the buccal and distal site (P=.006) from baseline to 1-year follow-up. Conclusions Narrow diameter implants are a reliable treatment for replacing a missing lateral incisor in patients with a cleft palate at 1 year, with an implant survival rate of 100% and implant success rate of 94% using the established criteria. A negative association was found between the bone mineral density and the implant stability in the alveolar cleft site of a patient with a cleft palate. The peri-implant soft tissue probe depths exhibited significant change during the first year.

Statement of problem The accuracy of single implant placement is critical, as errors may cause problems with vital structures intraoperatively, as well as postoperatively with the prostheses. These issues may be exacerbated in complete-arch edentulous treatments requiring relative accuracy among multiple implants, particularly with prefabricated prosthetic structures. Purpose The purpose of this clinical study was to determine the accuracy of dental implant placement by using haptic robotic guidance in completely edentulous participants. Material and methods In a prospective single-arm clinical study, 5 qualified participants elected to receive dental implants placed by using haptic robotic guidance to restore either the maxillary or mandibular arch, or both, with complete-arch implant-supported prostheses. Three dual-arch participants and 2 single-arch participants resulted in 38 endosteal dental implants being placed. A virtual preoperative restorative and surgical plan was created before surgery. This plan was matched to the surgical workspace on the day of surgery by using a bone-mounted fiducial splint fabricated from a cone beam computed tomography (CBCT) scan. Intraoperatively, the surgeons maneuvered a handpiece attached to the robotic guidance arm, osteotomies were created with a haptically constrained handpiece, and the implants were placed with 3-dimensional haptic constraints as per the virtual plan. Postoperative CBCT scans allowed the evaluation of the deviations of the actual implant placement relative to the plan. Results Twenty-three implants were placed in the mandible and 15 in the maxilla. The mean ±standard deviation global angular deviation was 2.56 ±1.48 degrees, while the crown of the placed implant showed a deviation from the plan of 1.04 ±0.70 mm and the apex of 0.95 ±0.73 mm. The signed depth deviation was 0.42 ±0.46 mm proud. No adverse events were reported. Conclusions This clinical series for treating completely edentulous patients by using haptic robotic guidance was found to be safe and accurate. While further longer-term clinical studies are necessary to measure outcomes and to assess differences as compared with nonrobotic implementations, haptic robotic preparation appears to confer additional intraoperative advantages over other techniques for treating completely edentulous arches.

Evidence to validate the routine use of angled screw-channel abutments in the anterior maxilla is sparse. If properly planned, they might provide surgical and prosthetic benefits.The purpose of this observational study was to determine the prevalence of digitally placed implants in the anterior maxilla that would allow screw-retained implant-supported restorations with either a straight or an angled screw-channel abutment.Two hundred cone beam computed tomography (CBCT) scans met the inclusion criteria for retrospective analysis and digital implant planning. Virtual implants were planned for randomly selected anterior maxillary teeth by using the anatomic crown and root position. Virtual abutments of varying angulation were attached to the implants to determine the ability to screw retain a restoration with either a straight or an angled screw-channel abutment.One hundred fifty-two (76%) sites required an angled screw-channel abutment to enable screw retention. Forty-eight (24%) sites allowed screw retention with a straight abutment. The percentage of implants requiring angled or straight abutments varied significantly among anterior teeth (P.005). One hundred nine (71.7%) angled screw-channel abutment sites required a 5-degree abutment, 41 (26.9%) required a 10-degree abutment, and 2 (1.3%) required a 15-degree abutment. Among the anterior teeth, lateral incisors presented a greater need for angled screw-channel abutments. None of the implants in the present study needed cement-retained restorations.Angled abutments allowed for screw-retained restorations on digitally planned implants in the anterior maxilla. The required angular correction to a screw-retained restoration was ≤15 degrees. Screw-retained restorations were frequently achievable (76%) with the use of angled screw-channel abutments or with straight abutments (24%), and lateral incisors presented a greater need for angled screw-channel abutments.

Consistent findings about the relationships between jaw deformity and the occlusal plane are lacking.The purpose of this clinical study was to explore the relationships between the occlusal plane and jaw deformity by measuring data obtained from cone beam computed tomography (CBCT) scans.Reconstructed images simulated by using the Materialise Interactive Medical Image Control System (Mimics) software program of CBCT data of 80 participants with facial asymmetry and 42 participants from the normal control group were measured with a new 3-dimensional geometric morphologic measurement system. Fifteen craniofacial surfaces were marked at a point, line, or plane, measuring correlation distances and angles to analyze the relationship between jaw deformity and the inclination of the occlusal plane and other relevant facial features. The Student t test was used to analyze whether the difference in the occlusal plane between the jaw deformity group and the normal group was statistically significant (α=.05). The Pearson correlation was used to analyze the correlation among the jaw deformity, the occlusal plane, and other landmarks, and linear regression was used to analyze the relationships among them.A significant difference was found between the occlusal plane of the jaw deformity and that of the normal group (P.001) and a significant positive correlation between the degree of mandibular deformity and the inclination of occlusal plane (P.001). A linear relationship was found between the linear regression equation of the angle of the left occlusal plane and the midsagittal sagittal plane Y and the distance between the mental apex of chin and the midsagittal plane X (the mandibular deflection to the right was defined as positive) as Y=90.646+0.388X. Statistically significant differences were found in the deviation of the chin vertex from the midsagittal plane and the distance between the midlines of the maxillary and mandibular central incisors by more than 2 mm (P.001).A positive correlation was found between the inclination of the occlusal plane and the degree of jaw deformity, with a linear relationship between them. These findings provide a theoretical basis for the clinical reconstruction of occlusal relationships with jaw deformity.

Objectives This study aimed to determine the correlation between alveolar cleft volume and fenestration and dehiscence in the adjacent alveolar bone in patients with unilateral cleft lip and palate (UCLP) using cone-beam computed tomography (CBCT) sections. Materials and methods In this descriptive, cross-sectional study, CBCT scans of 68 non-syndromic patients with UCLP aged between 6 and14 years were selected. All patients were treated in Iran and had undergone lip and palate repair surgery within the first 3 to 18 months after birth. CBCT scans had been taken after orthodontic expansion and prior to alveolar bone grafting surgery. Cleft volume, fenestration and dehiscence were assessed using Mimics software. Data were analyzed using independent t-test, Kruskal-Wallis test, Spearman's correlation coefficient and logistic regression model. Results The mean alveolar cleft volume was 628.66±172.84 mm3. There was a significant negative correlation between cleft volume and fenestration (P Conclusion The Mimics software can be successfully used to estimate the cleft volume prior to surgical procedures in UCLP patients. The results suggest that the alveolar cleft volume can be used as an aid to assess the periodontal condition of adjacent teeth. The cleft volume has a negative and positive correlation with fenestration and dehiscence respectively.

Statement of problem A custom emergence profile offers the ideal horizontal dimensions for an anatomic healing abutment. However, developing such an emergence profile can be a time-consuming and complex process. Purpose The purpose of this study was to develop a mathematical formula defining horizontal cervical tooth geometry to design prefabricated, tooth-specific, healing abutments. Material and methods Cone beam computed tomography (CBCT) horizontal cross sections of 989 teeth on 54 participants were measured. For anterior and premolar teeth, 2 perpendicular ellipses were fitted onto the cervical tooth cross section that was defined by 3 parameters. The lingual ellipse followed the lingual outline of the tooth, and its diameter was the largest mesiodistal diameter of the tooth (parameter “a”); its buccolingual radius became parameter “b.” The buccal ellipse was perpendicular to the lingual ellipse and followed the buccal outline of the tooth. The buccolingual radius of the smaller ellipse became parameter “c.” For molars, the first ellipses followed the mesial outline of the tooth, and its larger diameter (parameter “a”) matched the largest buccolingual diameter of the tooth. Its smaller radius became parameter “h1.” The second ellipse was parallel to the first ellipse and followed the distal outline of the tooth. Its larger diameter became parameter “b”, and its mesiodistal diameter became parameter “h2”. Statistical differences between parameters were evaluated by the linear mixed model (α=.05 after Bonferroni adjustment). Pairwise comparisons were made separately for each parameter of the molars and separately for each parameter for the anterior teeth plus premolars. Teeth were put into the same parameter cluster if no significant differences were found between them for a specific parameter. If neither parameter (4 for molars and 3 for the other teeth) was different for 2 teeth, they were put into the same abutment cluster. The abutment clusters determined the type of anatomic healing abutment. The areas were calculated from the developed mathematical formula by using the parameters. In addition, cervical areas of 106 randomly chosen teeth were measured directly with a photo-editing software program. A computer algorithm was used to select 5 CBCT scans from the 54 by using the simple randomization method. The agreement between the 2 methods was evaluated by Bland-Altman analysis. Results The lower and upper limits of agreement between the 2 methods were -8.57 and 7.36 mm2, respectively, with no bias (-0.61 mm2, P=.224). Significant differences were found between most parameters among the 14 tooth types (P Conclusions The cervical tooth cross section can be accurately defined by combining 2 elliptical elements. A comprehensive array of tooth specific emergence profiles can be provided by just 12 different prefabricated abutments, designed as per the recommended parameters.

Statement of problem In spite of a digital workflow playing an important role in the intraoral prosthetic rehabilitation of patients with head and neck cancer, information about how it has been implemented and its clinical implications is sparse. Purpose The purpose of this systematic review was to evaluate the use of a digital workflow in the intraoral prosthetic rehabilitation of patients with head and neck cancer by analyzing the frequency and type of the digital procedures used. Material and methods Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. The following terms were applied for the search conducted in the MEDLINE-PubMed, Cochrane, and SciELO databases: (prosthesis OR dental OR rehabilitation) AND (digital OR CAD-CAM OR intraoral scanner) AND (Cancer OR head neck). Articles that specified data on intraoral prosthetic treatment and analyzed the use of a digital workflow in the different prosthetic phases such as digital scanning and computer-aided design and computer-aided manufacturing (CAD-CAM) in patients with head and neck cancer were included. Data from the frequency and type of digital procedures were analyzed. Results Thirteen articles were included, and all had incorporated CAD-CAM techniques in at least 1 of the prosthetic treatment stages (scanning, design, and/or fabrication). Only 1 patient was rehabilitated by using a completely digital workflow. The most frequent prosthetic treatment was an obturator (82.6%). Regarding the image capture method, the most used method was cone beam computed tomography (CBCT) (60.9%). Conclusions Most reports described the partial use of a digital workflow in the intraoral prosthetic rehabilitation of patients treated for head and neck cancer. A digital workflow is used for specific stages but not for the entire process. More studies are needed to evaluate digital systems, ideally comparing parameters with the conventional method, and to determine whether this technique has more relevant clinical implications.

Objectives. The mounting of the plaster casts on articulator procedure is routinely performed in orthognathic surgery to assess canting of the maxillary occlusal plane, but the currently used protocols and reference plane could be source of errors which affect reliability. Nowadays the assessment of canting of the maxillary occlusal plane could be also performed with an entirely digital protocol. Aim of the study was to propose a method to evaluate canting in patients affected by Unilateral Condylar Hyperplasia, comparing the measurements performed on digital models matched on CBCT with those made on traditional articulator. Materials and methods. A retrospective cross-sectional study was designed on 20 patients affected by vertical Unilateral Condylar Hyperplasia treated in the Units of Orthodontics and Maxillo-Facial Surgery. The canting of the maxillary occlusal plane was measured on plaster casts mounted on the conventional articulator and the measures were compared with those made on digital models matched on CBCT, according the protocol developed in our Unit. Molar, canine and basal difference were measured. To compare the two protocols and to test the agreement, we performed descriptive statistics, comparison between means and Bland Altman analysis. P value was set at 0.05. Results. Statistic comparison demonstrated agreement between measurements performed with the digital protocol and conventional physical method. Conclusion. Measurements of canting with digital protocol are comparable to the physical standard method. A total digital protocol allows faster availability and storage of patient's data and better communication between orthodontist and maxillo-facial surgeon, especially in patients affected by three-dimensional malocclusions.

Statement of problem Adjusting an interim screw-retained crown made of acrylic resin for maintenance of peri-implant soft tissues after immediate implant insertion requires accuracy and time. Assessments of these factors by using digital techniques are sparse. Purpose The purpose of this clinical study was to describe a technique to fabricate an acrylic resin interim crown by using the data acquired from a cone beam computed tomography (CBCT) scan. The 3D tomography files were converted to a standard tessellation language (STL) file format used to print or to mill the interim crown with a technique called digital immediate tooth restoration (DITR). Additionally, the chair time spent during the prosthetic phase was evaluated in comparison with a protocol in which a standard interim crown (SIC) was fabricated with an indirect-direct technique. Material and methods Patients who needed to replace a single nonrestorable tooth were treated from February to June 2018 with an immediately placed implant and an acrylic resin screw-retained interim prosthesis that was connected to the implant immediately after placement of the implant. The participants were divided into 2 groups according to the acrylic resin interim crown fabrication technique: group DITR and group SIC. The average time to finalize the prostheses was compared between the groups. The total chair time (TCT) taken for the adaptation of the interim crown was noted and distinguished in 3 different times corresponding to each phase of adaptation of the interim restoration of the interproximal contact areas (CT1), adaption of the postextractive alveolar bone walls (CT2), and adaption of the occlusal contacts (CT3). For each time, the number of changes (N-CT1, N-CT2, N-CT3, and TN) needed to complete each prosthetic phase was also marked and observed. Generalized linear mixed models and generalized linear models were used for data analysis. All the sites were definitively restored with a screw-retained crown after 6 months of healing, and the participants were provided with standard hygiene recall appointments for the next year. Results A total of 82 crowns at sites distributed across the mandible and the maxilla were included in the study. Thirty-five were restored with an SIC and 47 with a DITR interim crown. None of the implants were lost during the 18-month follow-up period. The analysis of the chair times registered for the adaptation of the interim crown to the implant healing abutment and to the neighboring teeth between the 2 groups showed a reduction if a DITR interim crown was used (average CT1 of 15 ±14 seconds, CT2 of 2 ±5 seconds, CT3 of 59 ±19 seconds, and TCT of 76 ±28 seconds for group DITR and average CT1 of 135 ±27 seconds, CT2 of 185 ±30 seconds, CT3 of 73 ±16 seconds, and TCT of 394 ±61 seconds for group SIC). The number of corrections to finalize the interim crown adaptations was lower for the group DITR (0.81 ±0.74 for N-CT1, 0.19 ±0.39 for N-CT2, and 2.81 ±0.74 for N-CT3) when compared with the number of corrections needed for the group SIC (4.37 ±0.81 for N-CT1, 5.57 ±0.77 for N-CT2, and 3.86 ±0.64 for N-CT3). Conclusions The data from CBCT scans led to interim acrylic resin crowns that needed fewer adjustments with the immediate implant placement and interim restoration approach, reducing chair time.

This article introduced a digital workflow by using data merging and a computer-aided design and computer-aided manufacturing (CAD-CAM) milled surgical guide for an esthetic crown lengthening procedure. The superimposition of intraoral scanning, digital photographs, cone beam computed tomography, and a CAD-CAM surgical guide should increase the predictability of esthetic crown lengthening surgery.

Background To measure the motion of polyethylene insert and implant components of mobile-bearing total ankle replacement (TAR) by cone-beam CT scanning. Methods 10 TAR patients with high amount of clinical motion after the CCI implant (Ceramic Coated Implant; Wright Medical Technology, Arlington, TN, USA) with average age at operation 64,3 years (range 47–84) and average clinical total range of motion 42 degrees (range 35–55) were included. Results The average total range of motion between the insert and the tibial component was 0.8 mm (range 0–2) in the coronal plane, and 2.9 mm (range 1–6) in the sagittal plane. There was wide variation in the axial rotation measurements between the components. Conclusion We found measurable motion between the mobile-bearing insert and the tibial component in all planes. The relevance of this motion to the function and long-term survival of the TAR remains to be determined.

The aim of this study was to evaluate the position of the mandibular canal (MC) before and after bilateral sagittal split ramus osteotomy (BSSRO) using cone-beam computed tomography (CT), and to compare the position of the MC in Class II and Class III patients in the preoperative period. Patients were divided into two groups: Class II (n = 38) and Class III (n = 41). Measurements of the superior, inferior, buccal, and lingual distances of the MC in relation to the cortical bone were taken at three levels in the proximal segment of the mandible. Results were analysed using the Kruskal-Wallis test (p < 0.05). In the Class II group the superior distance of the MC at levels 2 and 3, and the inferior distance at level 3 significantly decreased after BSSRO. In the Class III group, no significant differences were found at any level, and the inferior distances at all levels were smaller preoperatively than those in the Class II group. In the Class II group the position of the MC altered in relation to superior and inferior cortical bone after BSSRO. However, the position of the MC remained stable in the Class III group. Our results also suggest a deeper cut in inferior cortical bone in Class III patients.

Statement of problem An accurate surgical template for guided implant surgery is essential for the success of an implant restoration. However, reports on the accuracy of digitally designed and computer numeric controlled (CNC) machine-milled surgical templates are sparse. Purpose The purpose of this in vitro study was to investigate the accuracy of an implant surgical guide digitally designed by using data from cone beam computed tomography (CBCT) scans and milled with a 5-axis CNC machine. Material and methods Six representative radiographic templates were prepared from radiopaque resin plates. For each guide, a CBCT scan was made, and the extracted Digital Imaging and Communications in Medicine (DICOM) data were imported into a planning software program (ORGANICAL Dental Implant). Nine implants were virtually designed for each guide. The design data were imported into a 5-axis CNC machine, and the radiographic guides were fixed onto the CNC machine (Organical Multi S). Bore holes for surgical guide sleeves were milled directly in the radiographic template, which was converted into a surgical template. After the milling process, the surgical guides were scanned by using a laboratory cast scanner. The deviation between the position of the sleeve bore hole in the milled template and that in the virtual implant planning was digitally calculated. Results The mean global deviation of the surgical guide was 0.16 ±0.06 mm in the circle center of the sleeve top, and the mean angular deviation was 0.61 ±0.40 degrees. The sleeve-implant distance and the sleeve axis angle showed no significant influence on the in vitro accuracy of the implant surgical guide. Conclusions The mean deviation of the surgical guide prepared by using the virtual planning software and 5-axis CNC milling procedure in this study was 0.16 ±0.06 mm in the center of the sleeve top. Thus, the guide had acceptable precision.

The aim of this study was to evaluate the prevalence and length of the anterior loop (AL) of the inferior alveolar nerve, nerve emergence from the mental foramen, and prevalence of sensory disorders after implant placement in the interforaminal region. Four hundred and fifty hemimandibles (225 patients) were evaluated using cone beam computed tomography and panoramic radiographs. Information on the presence of sensory disorders was obtained from the medical records. AL prevalence was 13.6% and mean AL length was 1.25 mm. The false-negative rate for the identification of the AL using panoramic radiography was 58.6%. Straight nerve emergence from the mental foramen was the most prevalent (62.7%), followed by anterior (21.8%) and posterior (15.6%) emergence. The incidence of sensory disorders was 4.4%, and 1.1% were related to the presence of the AL. When implants were placed within the planned distance of the mental foramen or further, 1.2% had sensory problems associated with the presence of the mandibular incisive canal. In cases of distances smaller than planned, 12.9% had sensory alterations. Only five (1.1%) had the AL, with a length between 0 and 4.5 mm. However, in four cases, the planned distance was respected and, even so, there was a sensory disorder. Posterior nerve emergence from the mental foramen was associated with a higher prevalence of AL.

Objective To compare the 2 surgically assisted rapid maxillary expansion (SARME) techniques, the conventional 2-segment osteotomy between maxillary central incisors and the 3-segment osteotomy between maxillary lateral incisors and canines bilaterally. Authors hypothesized that the 3-piece would provide better bone expansion. Study Design A pilot study was conducted; 19 patients were divided into 2 groups: conventional 2-segment osteotomy (10 patients) and 3-segment osteotomy (9 patients). Dental and skeletal measurements of the preoperative and postoperative cone beam computed tomography images were analyzed. Pre- and postoperative periodontal probing was performed, patients’ cosmetic perception was evaluated in a colored visual analog scale (VAS), and surgical time was measured with a regular chronometer. Results Three-segment SARME resulted in greater bone expansion (5.12 vs 6.20 mm; P = .016), less molar inclination (7.16 vs 3.57 degrees; P = .028), better patient cosmetic perception (3.13 vs 7.68 in a VAS; P = .000), and longer surgical time (43 vs 52 minutes; P = .026). Furthermore, the 2-segment group presented necrosis of 1 central incisor. Conclusions Results suggest that 3-piece SARME is more effective for bone expansion of the maxilla.

The purpose of this study was to determine whether the use of custom osteosynthesis plates increased the accuracy of proximal segment position following bilateral sagittal split osteotomy in a cohort of 30 patients when compared to a control group of 25 patients who had surgery with conventional plates. Surgery was performed by a single surgeon between October 2015 and December 2017. Post-surgical cone beam computed tomography scans were segmented using Mimics Innovation Suite (Materialise NV), and surface-based superimposition was achieved using ProPlan CMF (Materialise NV). However, there was a tendency for the rotational error to be smaller in the custom group than in the control group. The root mean square error in both groups and for all variables fell within clinical parameters of 2 mm and 4°. In conclusion, the results of this study indicate that customized mandibular fixation plates do not necessarily improve the accuracy of the proximal segments post-surgically; however they may be of benefit in individual patients.

A complete digital workflow to remove a cement-retained implant-supported crown by using an additively manufactured implant abutment screw-access guide is described. The existing cone beam computed tomography (CBCT) scan was superimposed on the digital scans of the patient, which facilitated the visualization of the implant abutment screw access and guided the design of the device. Advantages of the technique described include the precise translation of the implant abutment screw access, safe removal of the implant crown, and conservative clinical intervention.

The purpose of this three-dimensional cone beam computed tomography (CBCT) study was to identify the difference between monocortical fixation (MCF) and bicortical fixation (BCF) in mandibular canal penetration after bilateral sagittal split osteotomy (BSSO) to correct mandibular prognathism, where interosseous fixation was done by BCF or MCF. CBCT was performed 1 week postoperatively and Dolphin 3D software was used to assess direct penetration of the mandibular canal by either type of screw. The primary outcome variable was the presence or absence of mandibular canal penetration and was categorized as a binary coded variable. The BCF and MCF groups were compared by χ2 test, and the odds ratio for canal penetration was estimated. Multiple logistic regression was performed to identify factors related to canal penetration. A total of 118 patients were included. The MCF group had only 6% canal penetrations (3/50 patients) and the BCF group had 58.8% canal penetrations (40/68 patients). The regression model showed that BCF was the only factor causing mandibular canal penetration, with an adjusted odds ratio of 52.5. Awareness of the increased risk of canal penetration with BCF and potential nerve injury might influence case selection.

Background To report the early outcomes of cone beam computed tomography (CBCT) using last generation 3D C-arm in patients undergone advanced endovascular aortic aneurysm repair (AdEVAR) and to identify risk factors that may predict any un-planned procedures. Methods Patients undergone AdEVAR between December 2017 and December 2018 were enrolled. Final CBCT was performed in all patients after digital subtraction angiography. Primary end points were the incidence of any positive findings and the following unplanned procedures intended as any endovascular manoeuvre performed to fix such technical defect. The secondary endpoints were comparison of outcomes between patients with positive findings undergone unplanned procedure (Group A) versus patients without findings (Group B). Results 132 patients underwent endovascular treatment for aortic aneurysm. Of these, 22 (33%) fenestrated-branched endovascular aneurysm repairs (F-BEVAR), 21 (29%) EVAR with iliac branch devices, 19 (26%) abdominal and 10 (14%) thoracic EVAR were included in the study. Unplanned procedures after CBCT were necessary in 22 patients (31%). Patients in both groups were similar excepted for BMI >25 kg/m2 (55% vs. 26%), hostile iliac anatomy (64% vs. 32%) and previous aortic treatment (73% vs. 32%) (P Conclusion The use of CBCT, especially in challenging scenarios, can reveal technical defects and may potentially limit the need for late reintervention. Patients undergone previous aortic surgery should be carefully evaluated and routine CBCT should be performed.

The aim of this study was to perform a three-dimensional evaluation of the skeletal relapse of the proximal and distal mandibular segments following isolated bilateral sagittal split osteotomy advancement surgery. One hundred consecutive patients (mean age 25.8±11.7 years), comprising 65 female patients (mean age 26.4±12.1 years) and 35 male patients (mean age 24.6±11.0 years) requiring mandibular advancement without genioplasty, were enrolled prospectively in the study. Cone beam computed tomography scans were acquired for each patient at three time-points: preoperatively, immediately (1-6 weeks) after surgery, and 1 year after surgery. A validated tool was utilized to assess the surgical movement and relapse. Based on percentage, the majority of the distal and proximal translational and rotational movements relapsed within the range of ≤2mm and ≤2°. The distal segment revealed a significant relapse in a posterior, inferior, and clockwise pitch direction. Both left and right proximal segments showed a significant translational relapse in the medial, posterior, and superior direction. Amongst the rotational parameters, proximal segments relapsed significantly in clockwise pitch, clockwise roll, and counterclockwise yaw direction. Overall, both distal and proximal bone segments showed a clinically acceptable translational and rotational stability. The proximal segments torqued towards their original position with a reduction of flaring. ispartof: INTERNATIONAL JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY vol:51 issue:1 pages:113-121 ispartof: location:Denmark status: published

Background/purpose: The nature of susceptibility to condylar resorption after orthognathic surgery can be different between skeletal Class II and Class III populations, which was addressed by few in the past. The aim of the present study was to use cone-beam computed tomographic (CBCT) images to investigate the displacement and morphological changes of temporomandibular joints (TMJs) in patients received orthodontic treatment combined with orthognathic surgery. Methods: Both Class III (n = 34) and Class II (n = 17) patients were compared through overall and regional superimpositions of the initial and posttreatment CBCTs. Two-sample t-test was used to identify significance between group differences. Pearson's correlation coefficient was used to address changes of TMJ and the amount of setback or advancement. Results: The axial ramal angle increased significantly in Class III group and decreased in Class II groups after orthognathic surgery (p

Objectives: The purpose of this systematic review was to answer the focus question: “Could the gray values (GVs) from CBCT (cone beam computed tomography) be converted to Hounsfield units (HUs) in multidetector computed tomography (MDCT)?” Methods: The included studies try to answer the research question according to the PICO strategy. Studies were gathered by searching several electronic databases and partial grey literature up to January 2021 without language or time restrictions. The methodological assessment of the studies was performed using The Oral Health Assessment Tool (OHAT) for in vitro studies and the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) for in vivo studies. The Grading of Recommendations Assessment, Development and Evaluation (GRADE system) instrument was applied to assess the level of evidence across the studies. Results: 2710 articles were obtained in Phase 1, and 623 citations remained after removing duplicates. Only three studies were included in this review using a two-phase selection process and after applying the eligibility criteria. All studies were methodologically acceptable, although in general terms with low risks of bias. There are some included studies with quite low and limited evidence estimations and recommendation forces; evidencing the need for clinical studies with diagnostic capacity to support its use. Conclusions: This systematic review demonstrated that the GVs from CBCT cannot be converted to HUs due to the lack of clinical studies with diagnostic capacity to support its use. However, it is evidenced that three conversion steps (equipment calibration, prediction equation models, and a standard formula (converting GVs to HUs)) are needed to obtain pseudo Hounsfield values instead of only obtaining them from a regression or directly from the software.

Background The relationship between horizontal condylar angle (HCA) measurements and radiographically detectable morphological changes of the condyle in patients with temporomandibular disorder (TMD) is an area of controversy in dentistry. Aim This study sought to determine the effect of the HCA on radiographically morphological changes in the condyles of asymptomatic and symptomatic patients with TMD. Material & methods Cone beam computed tomography (CBCT) scans were used of patients with 146 temporomandibular joints (TMJ) with and without symptoms of TMD. The reconstructed axial plane was adjusted to depict the condyle in maximum width. The HCA was established and measured as the angle formed between the condylar long axis intersecting with the coronal plane. Each condyle long axial was determined independently from the other joint by two oral and maxillofacial radiologists. The average of the readings from the two examiners was used for statistical analysis. Results Based on the clinical symptoms, the mean of the HCA in the symptomatic joint was 27.69°, which was slightly greater than the angle measured in asymptomatic patients of 25.6°; however, this was not a statistical difference. No significant differences existed in the mean of the HCA between the joint with and without radiographic arthritic findings in both groups. In both groups, none of the arthritic findings manifested in the affected joint that had influenced the HCA. Conclusion The HCA was increased in the symptomatic group but had no direct influence on joint's morphological changes in the asymptomatic and symptomatic patients.

This study used three-dimensional cone beam computed tomography (CBCT) to assist the accuracy of open reduction and internal fixation (ORIF) for the unilateral subcondylar fracture and the long-term temporomandibular joint (TMJ) function impairment. Bilateral TMJs were analyzed postoperatively on CBCT images, involving the following three-dimensional (3D) parameters: condylar position and inclination; circumferential joint space, ramus, and mandible length; and the volumetric joint space. The inclusion criteria for adult patients included having a displaced fracture5°, a shortening in ramus length2 mm, and mouth opening limitation. The non-fracture side was used as the comparison group. The Helkimo index was employed for the clinical assessment of the outcomes, while the paired student t-test and Pearson coefficient test were used to compare both sides. The study included 60 joints in 30 consecutive patients. The condylar inclination to the horizontal plane on the fracture and non-fracture sides was 9.29 ± 3.9°, 12.46 ± 4.2°, (p 0.001) and was positively related to the subjective (Helkimo Hi) and objective (Helkimo Di) clinical outcomes. In contrast, the condylar position to the midsagittal plane in the fracture and non-fracture sides was 51.95 ± 3.5 mm, 50.17 ± 3.6 mm (P = 0.038), and was positively related to the objective outcomes. Additionally, the objective outcome was negatively related to the change of the posterior joint space. CONCLUSION: The three-dimensional assessments seem to demonstrate that the ORIF is an accurate approach for obtaining a three-dimensional reduction to the displaced subcondylar fracture.

Introduction The aim was to assess the prevalence of Mid Mesial Canal (MMC) in the first and second mandibular molars in a Saudi subpopulation sample and assess its relation to side, gender, and age using Cone beam computed tomography (CBCT). Methods The CBCT scans at King Saud University Dental Hospital between 2016 and 2019 were reviewed and filtered. The MMC of the mandibular molars were assessed according to Pomeranz et al. classification which was: (1) independent; (2) fin; (3) confluent with the mesiobuccal canal; and (4) confluent with the mesiolingual canal. Three calibrated observers examined the MMC on all planes at both sides. Age and gender factors were used to analyze that prevalence. A chi-squared test was used and (P ≤ 0.05) was considered to be statistically significant. Results 395 patients, and 1377 teeth met the inclusion criteria. The total number of mid-mesial canals was 12 (0.9%): nine at the mandibular first molar (1.3%) and three in the mandibular second molar (0.4%). The most common type of mid-mesial canal was confluent (n = 10), of which 6 fused with the mesiobuccal canal and 4 fused with the mesiolingual canal. Two canals were of the fin type, and there was no instance of independent mid-mesial canal. There was no significant difference between all variables: tooth type, tooth side, patient gender, and patient age group (p > 0.05). Conclusion In this study, the most common MMC configuration was the confluent type followed by the fin type and no independent type were found. The patient side, gender and age did not influence the prevalence of the MMC.

Background & objective In current clinical dental practice radiographic imaging plays a major role in exploring the relationship between the maxillary sinus floor (MSF) and maxillary posterior teeth root apices, especially when there is an involvement of pathology in the periapical area that may lead to infectious, inflammatory or traumatic changes in the maxillary sinus (MS). It is also essential for exact implant placement, and therapeutic and surgical plans. The prevalence of different forms of anatomic relationship of the MSF to posterior root apices from one population to another is large. Hence the current research was conceived to evaluate the horizontal and vertical relationship forms of posterior root apices to the MSF in the Al-Qassim population of Saudi Arabia using Cone Beam Computed Tomography (CBCT). Materials and methods To conduct the study, a total of 200 patients' data (100 male and 100 female) were taken from the archives. The linear distances of the root apices to the MSF were measured for maxillary posterior teeth. On cross-sectional CBCT images, the Kwak et al. criteria were used to assess the horizontal and vertical relationships between the root apices of maxillary posterior teeth and the MSF. Results The mean distance between the apices of the maxillary second premolar ranged from 4.63 mm to 6.49 mm. The mean value of the distance between the apices of the posterior teeth and the MSF had a range of 0.68 ± 0.39 mm on the disto-buccal root (DBR) of the maxillary right second molar to 3.93 ± 1.26 mm on the palatal root (PR) of the maxillary left first molar. A similar result was observed in the maxillary second molar DBR in the male group (0.68 ± 1.17 mm) and the female group (0.69 ± 1.17 mm). The most frequently observed vertical relations were type 2 and type 2H horizontal relations. Conclusion This study concludes that maxillary molar roots show greater proximity with the MSF when compared with premolars, and that the type 2 vertical and type 2H horizontal distribution suggests that the anatomy of each tooth and the maxillary sinus floor should be evaluated by CBCT prior to treatment planning.

Introduction Localization of impacted maxillary canine (IMC) position is essential in orthodontic treatment for accurate orthodontic treatment as well as prognosis. Objectives This study aimed to: 1- investigate the relationship between the locations of IMC in panoramic radiograph (PR) using sectors in relation to their labio-palatal position in cone beam computed tomography (CBCT): 2- report the incisor root resorption in CBCT in relation to its sector location of IMC in PR. Material and Methods The study is a retrospective imaging assessment of 60 IMCs in multiple centers in Riyadh, Saudi Arabia. Sector location of IMC was determined on the PR and correlated with each of their labio-palatal positions and resorption of the root of permanent incisors using CBCT. Results There is a significant correlation between sector location and impaction location of IMC. No statistical correlation was found between IMC sector location and lateral incisor root resorption, whereas a significant correlation was found between sector location and central incisor root resorption. Conclusions For Sectors I and II, IMC tended to be in either the mid-alveolus or labial location, whereas Sectors III and IV tended to show palatal impaction. Therefore, sector could be a good tool for localization of IMC and to predict the possibility of incisor root resorption.

Introduction Age-at-death estimation is an essential part of the identification process of individuals in many forensic dentistry cases where identity of the individual cannot be resolved by visual recognition or other means. Dental age estimation in adults is more of a challenge as most teeth complete their development by the age of 18 years. Aim This study aims at using the mesio-distal (MD) pulp-to-tooth ratio taken at the cervix of upper third molars (UM3) to estimate age at the time of radiographic imaging. Materials and Methods A set of 135 Cone-beam computed tomography (CBCT) radiographs of UM3s for a random sample of 135 Jordanian adults (65 females, 70 males; age range = 18–63 years, mean age = 34.4 years, SD = 11.2 years) were used. Both pulp and tooth MD diameters were measured at the cervix. MD pulp-to-tooth ratios for UM3s were correlated with age. Results Statistically significant negative moderate correlation was found between the age of the individual and the cervix MD pulp/tooth ratio (r = −0.516). This indicates that only 26.6% of the variation in age can be explained by the cervix MD pulp-to-tooth ratio. Conclusions This study concludes that cervix MD pulp-to-tooth ratio of UM3s, although apparently stronger than that of lower M3s (r = −0.361), is not a sufficiently reliable estimator of age in adults, and this is perhaps attributed to the greater variability in the time line of third molars development.

Objective: CBCT (cone beam computed tomography) analysis of condyle morphometry, to investigate the gender differences, symmetry and relationship with mandibular size. Materials and methods: This is a retrospective study. 800 CBCT scan obtained for the measurement of condyle in anterior-posterior and medio-lateral aspect using OnDemand 3D software. Participants were Saudi nationals of age above 18 years. 395 Males and 405 Females with the mean age of 38.2 ± 10.5 years. Right and left anterior-posterior width and medio-lateral width of the condyle were measured. Condyles were not isolated on the CBCT for volume measurement. Results: Mean right and anterior-posterior condyle width was 9.02 mm and 8.74 mm in males whereas in females it was 9.01 mm 8.69 mm respectively. For males mean medio-lateral width of the condyle in right and left side was 17.40 mm and 16.95 mm. For females, mean medio-lateral width of the condyle in right and left side was 17.14 mm and 16.93 mm. The prediction rate of gender was 57.2% for males and 53.3% for females. Statistically significant differences (p

Objectives The objective of this study was to estimate the possible number of cancer cases produced during 2019 in US dental offices from radiography, estimate the possible reduction in those rates resulting from use of intraoral rectangular collimation and selection criteria, and determine the frequency and quality of website radiation risk information and informed consent forms. Study Design An analysis of dental radiation examinations in 2014 to 2015 US national survey data, Nationwide Evaluation of X-ray Trends, and National Council on Radiation Protection and Measurements surveys was performed, in addition to an analysis of 2008 to 2020 Journal of Clinical Orthodontics national orthodontic surveys for radiographic examination frequencies. Lifetime attributable cancer risk estimates from US and European studies were used to generate the total dental and orthodontic office cancer totals. In total, 150 offices were examined online for the quality and frequency of risk information in websites and consent forms. Results The 2019 estimate for all office cancers is 967. Collimation and selection criteria could reduce this to 237 cancer cases. Most cancers arise from intraoral and cone beam computed tomography examinations, with 135 orthodontic cancers over 21 months (average treatment time). Collimation and selection criteria could reduce this to 68. Only 1% of offices use collimators or informed consent for radiography. The website and consent information were of poor quality. Conclusions Dentists are not following selection criteria or using collimators according to guidelines. Up to 75% of cancer cases could be avoided.

To investigate the technical success, safety and outcomes of transcatheter arterial chemoembolization (TACE) combined with simultaneous cone-beam computed tomography (CBCT)-guided microwave ablation (MWA) in small hepatocellular carcinoma (SHCC).Retrospective analysis of 66 lesions in 50 patients (38 men, 12 women) who underwent TACE combined with simultaneous CBCT-guided MWA for SHCC. After 1 month of treatment, the tumor responses were assessed using the mRECIST criteria, along with interventional-related complications and changes in hepatic and renal function. Moreover, progression-free survival (PFS) and overall survival (OS) were calculated.All patients achieved technical success. The mean target tumor size was 3.4 ± 0.7 (range, 2.2-4.9) cm. The mean energy, ablation duration per tumor, and the mean safety margin were 51.3 ± 8.4 kJ, 6.7 ± 0.8 minutes and 1.4 ± 0.6 cm, respectively. The 1-, 3-, and 5-year PFS rates were 90.0%, 65.4%, and 35.7%, respectively, with a mean PFS of 43.46 months; and the 1-, 3-, and 5-year OS rates were 98.0%, 89.8%, and 74.3%, respectively, with a mean OS of 54.90 months. Multivariate Cox regression analysis further illustrated that TACE combined with MWA in the treatment of a single tumor with a diameter of less than 3 cm was an independent protective factor for PFS and OS (p0.001). The patients had no major complications. Among the exceptions, one patient (2%) had an asymptomatic perihepatic effusion that resolved spontaneously, two patients (4%) developed massive right pleural effusion, requiring thoracic drainage, and another patient (2%) developed a hepatic subcapsular hemorrhage required interventional embolization.CBCT-guided TACE combined with simultaneous MWA was a safe and successful treatment of SHCC with a high technical efficacy.

Cone-beam CT (CBCT) applications possess potential for dose reduction in musculoskeletal imaging. This study evaluates the ultra-high-resolution CBCT prototype of a twin robotic X-ray system in wrist examinations compared to high-resolution multidetector CT (MDCT).Sixteen wrists of body donors were examined with the CBCT scan mode and a 384 slice MDCT system. Radiation-equivalent low-dose (CTDISubjective image quality in CBCT was superior to dose equivalent MDCT with p ≤ 0.03 for full-dose and p0.001 for low-dose scans, respectively. Median Likert values were 7/7 (reader 1 / reader 2) in full-dose CBCT, 6/6 in full-dose MDCT, 5/6 in low-dose CBCT and 3/3 in low-dose MDCT. Intraclass correlation coefficient was 0.936 (95% confidence interval, 0.897-0.961; p0.001), indicating excellent reliability. Objective analysis displayed smaller fractions of "indecisive" pixels with intermediate signal intensity for full-dose CBCT (0.57 [interquartile range 0.13]) compared to full-dose MDCT (0.68 [0.21]), low-dose CBCT (0.72 [0.19]), and low-dose MDCT (0.80 [0.15]) studies. No significant difference was observed between low-dose CBCT and full-dose MDCT.The new CBCT prototype provides superior image quality for trabecula and bone marrow in cadaveric wrist studies and enables dose reduction up to 75% compared to high-resolution MDCT.

OBJECTIVE: The objectives of this study were to assess observers' preference for standard screens (SSs) or medical displays (MDs) in visualizing difficult-to-diagnose radiographic dental abnormalities and their preference for dental filter tools when utilized with MD systems. STUDY DESIGN: A retrospective data set of 60 in vivo radiographs consisting of intraoral (n = 20), panoramic (n = 20), and cone beam computed tomography (n = 20) images was created. Three image display monitors, including an SS, an MD, and an MD with 3 dental filter configurations (bone-low density enhancement filter, tooth-high density enhancement filter, and a combined filter representing regular MD), were utilized to assess 4 observers' monitor preferences in detecting radiographically subtle dental abnormalities. The data were analyzed by using binomial distribution. A P value ≤.05 was considered statistically significant. RESULTS: Although observers expressed preference for MD for visualizing some abnormalities when examining intraoral and panoramic radiographs, MD was not preferred for detection of any abnormalities with cone beam computed tomography. There were no significant differences in preference for SS or MD overall (P ≥ .2024). Observers expressed significant preference for the filters in visualizing all but 2 abnormalities (P ≤ .0252). CONCLUSIONS: The use of MD monitors enabled with dental filter tools may be preferred for visualizing certain subtle abnormalities. ispartof: ORAL SURGERY ORAL MEDICINE ORAL PATHOLOGY ORAL RADIOLOGY vol:132 issue:4 pages:475-482 ispartof: location:United States status: published

BACKGROUND: The time of flight (TOF) cone beam computed tomography (CBCT) was recently shown to reduce the X-ray scattering effects by 95% and improve the image CNR by 110% for large volume objects. The advancements in X-ray sources like in compact Free Electron Lasers (FEL) and advancements in detector technology show potential for the TOF method to be feasible in CBCT when imaging large objects. OBJECTIVE: To investigate the feasibility and efficacy of TOF CBCT in imaging smaller objects with different targets such as bones and tumors embedded inside the background. METHODS: The TOF method used in this work was verified using a 24 cm phantom. Then, the GATE software was used to simulate the CBCT imaging of an 8 cm diameter cylindrical water phantom with two bone targets using a modeled 20 keV quasi-energetic FEL source and various TOF resolutions ranging from 1 to 1000 ps. An inhomogeneous breast phantom of similar size with tumor targets was also imaged using the same system setup. RESULTS: The same results were obtained in the 24 cm phantom, which validated the applied CBCT simulation approach. For the case of 8 cm cylindrical phantom and bone target, a TOF resolution of 10 ps improved the image contrast-to-noise ratio (CNR) by 57% and reduced the scatter-to-primary ratio (SPR) by 8.63. For the case of breast phantom and tumor target, image CNR was enhanced by 12% and SPR was reduced by 1.35 at 5 ps temporal resolution. CONCLUSIONS: This study indicates that a TOF resolution below 10 ps is required to observe notable enhancements in the image quality and scatter reduction for small objects around 8 cm in diameter. The strong scattering targets such as bone can result in substantial improvements by using TOF CBCT.

This study assessed the influence of voxel size and filter application in detecting second mesiobuccal (MB2) canals in cone-beam computed tomographic (CBCT) images.Using the OP300 CBCT system (Instrumentarium, Tuusula, Finland) and 3 voxel size protocols (80 μm, 125 μm, and 200 μm), we scanned 40 first molars: 20 with an MB2 canal and 20 without. All molars received silver palladium pins on the palatal root, whereas the non-MB2 molars were also filled with gutta-percha. Five oral radiologists assessed the presence of an MB2 canal under 3 filter application conditions: without filter, with sharpen 1 × filter, and with sharpen 2 × filter. Intra- and interobserver reproducibility was evaluated using the weighted kappa index. We compared the area under the receiver operating characteristic curves with SPSS Statistics v.20.0 (IBM Corp, Armonk, NY) using 2-way analysis of variance and the Tukey post hoc test with 5% significance level.Our analysis found median intra- and interobserver agreement values of 0.70 and 0.56, respectively. The 80-μm voxel with sharpen 1 × filter image group had the highest sensitivity, accuracy, and negative predictive values. As for specificity and positive predictive, the 80-μm voxel group without filter application presented the highest values. The areas under the receiver operating characteristic curve were higher in the 80-μm groups than in the 125-μm and 200-μm voxel size groups (P .05). We found no differences among the filters used (P = .22) or for the filter-voxel size interactions (P = .88).A smaller voxel size increased the accuracy in detecting MB2 canals, whereas the enhancement filters did not.

IntroductionIdeal endodontic access provides unobstructed entry to the pulp chamber and visualization of the canal orifices while preserving the maximum amount of tooth structure. The aim of this study was to implement the use of lasers to accurately and predictably access teeth to follow the principles of minimally invasive endodontics.MethodsTraditional, conservative, ultraconservative, bridge, truss, and orifice-directed accesses were performed. A computer-controlled 9.3-μm CO2 laser ablation system was assembled and coupled with custom software capable of combining cone-beam computed tomographic (CBCT) volumetric data with spatially calibrated digital images of teeth to provide an augmented reality environment for designing and preparing endodontic accesses. Twenty (N=20) sound posterior teeth with fully developed root canal systems were imaged with CBCT scans and accessed via laser ablation invitro.ResultsAll 20 (20/20) teeth were successfully accessed without iatrogenic errors. Volumetric renderings from post-access CBCT scans were used to verify the access and determine accuracy qualitatively. The volumetric measurements of hard tissue removed were as follows: traditional=39.41 mm3, conservative=9.76 mm3, ultraconservative=7.1 mm3, bridge=11.53 mm3, truss=19.21 mm3, and orifice directed=16.86 mm3.ConclusionsDigital image guidance based on feature recognition and registration with CBCT data is a viable method to address the challenge of dynamic navigation for accessing the pulp chamber. Modern lasers with high pulse repetition rates integrated with computer-controlled scanning systems are suitable for the efficient cutting of dental hard tissues.

Malpositioning of implants is one of the main factors leading to hard- and soft-tissue deficiencies. Whether static computer-guided implant placement increases accuracy and prevents malpositioning is unclear.The purpose of this in vitro study was to determine accuracy defined by trueness and precision (according to International Organization for Standardization 5725) of computer-assisted implant surgery (fully guided and partially guided) in comparison with freehand single implant placement.Implants (n=20) were placed fully guided (sleeve-bone distance of 2, 4, or 6 mm), partially guided (guide used for pilot drill), or free hand in identical replicas produced from a cone beam computed tomography (CBCT) scan of a partially edentulous patient. The achieved implant position was digitized by using a laboratory scanner and compared with the planned position. Trueness (planned versus actual position) and precision (difference among implants) were determined. The 3D-offset at the crest of the implant (root mean square between virtual preoperative planning and postoperative standard tessellation language file) was defined as the primary outcome parameter. The means, standard deviation, and 95% confidence intervals were analyzed statistically with 1-way ANOVA and the Scheffé procedure.Fully guided implant surgery achieved significantly lower 3D deviations between the planned and actual implant position with 0.22 ±0.07 mm (2-mm sleeve-bone distance) than partially guided 0.69 ±0.15 mm and freehand placement 0.80 ±0.35 mm at the crest (P.001). The distance among the implants in each group was again lowest in the fully guided group and highest in the freehand group.The static computer-assisted implant surgery showed high trueness and precision. The closer the sleeve to the bone, the more accurate and precise the method. Freehand implant placement was less accurate and precise than computer-assisted implant surgery (partially or fully).

Purpose: To measure and compare the accuracy of the linear dimensions of implant sites recorded from cone beam computed tomography (CBCT) images using Blue Sky Plan, coDiagnostiX, and RadiAnt. Materials and Methods: Five human dry skulls were imaged with a CBCT device then sectioned to obtain sample transverse cross-sections of the edentulous ridges, and the height and width of the ridge were measured with a digital caliper to provide the gold standard measurements. The CBCT datasets were exported in DICOM format and imported into the three test software programs which were used to obtain reformatted sectional images corresponding to the sample transverse cross-sections, and the height and width of the edentulous ridge was recorded using the linear measurement tool. Reliability of the measurements were measured using the intraclass correlation coefficient. One-sample t-test (test value: zero) was used to test the statistical significance of the mean of the absolute errors for each software program. Analysis of Variance with Repeated Measures was used to test the statistical significance of the difference between the means of the absolute errors obtained by the different software programs. Statistical significance was set at a p-value of 0.05. Results: The reliability of the gold standard and image measurements were excellent. All three software programs demonstrated a statistically significant mean absolute measurement error of between 0.43 and 0.56 mm (p-value

Aim To evaluate the impact of intraoperative cone beam computed tomography (CBCT) assessment for the surgical management of zygomatic bone fracture (ZF). Methods A prospective study was conducted on patients operated on for unilateral ZF during a two-year period. Repositioning of the fractured zygoma was assessed intraoperatively by measuring the position of malar eminences in three dimensions on CBCT. A difference of more than 2 mm between both sides was considered significant and the reduction was judged inadequate. Surgical procedure was adapted to intraoperative imaging findings. Results The surgical procedures of 47 patients treated for ZF were analyzed. In 15% of the cases (7 patients), the intraoperative CBCT showed an inadequate reduction while the morphological results seemed correct. Those patients benefited from an immediate correction of the reduction. From these 7 patients, reduction was optimized further without the need of osteosynthesis in one case, additional osteosynthesis was performed in 4 cases and 2 patients required both reduction and osteosynthesis revision. Conclusion Intraoperative CBCT control helps to achieve anatomic repositioning in case of ZF. It may reduce the risk of under-treatment and possible reoperation, and of over-treatment meaning systematic ORIF in all fractures.

In current clinical practice, noisy and artifact-ridden weekly cone-beam computed tomography (CBCT) images are only used for patient setup during radiotherapy. Treatment planning is done once at the beginning of the treatment using high-quality planning CT (pCT) images and manual contours for organs-at-risk (OARs) structures. If the quality of the weekly CBCT images can be improved while simultaneously segmenting OAR structures, this can provide critical information for adapting radiotherapy mid-treatment as well as for deriving biomarkers for treatment response. Using a novel physics-based data augmentation strategy, we synthesize a large dataset of perfectly/inherently registered planning CT and synthetic-CBCT pairs for locally advanced lung cancer patient cohort, which are then used in a multitask 3D deep learning framework to simultaneously segment and translate real weekly CBCT images to high-quality planning CT-like images. We compared the synthetic CT and OAR segmentations generated by the model to real planning CT and manual OAR segmentations and showed promising results. The real week 1 (baseline) CBCT images which had an average MAE of 162.77 HU compared to pCT images are translated to synthetic CT images that exhibit a drastically improved average MAE of 29.31 HU and average structural similarity of 92% with the pCT images. The average DICE scores of the 3D organs-at-risk segmentations are: lungs 0.96, heart 0.88, spinal cord 0.83 and esophagus 0.66. This approach could allow clinicians to adjust treatment plans using only the routine low-quality CBCT images, potentially improving patient outcomes. Our code, data, and pre-trained models will be made available via our physics-based data augmentation library, Physics-ArX, at https://github.com/nadeemlab/Physics-ArX., Medical Physics 2021

Introduction The purpose of this research was to assess the diagnostic accuracy of sella turcica bridging on lateral cephalograms when compared with true sella turcica bridging determined via cone-beam computed tomography (CBCT). Methods A cross-sectional study was conducted using CBCT images from which lateral cephalograms were generated. The study included 185 subjects (118 females and 67 males; age range, 10-30 years; mean age, 16.63 ± 4.20 years). Sella turcica landmarks and related measurements were calculated for both diagnostic modalities and analyzed by 1 examiner. Subjects were classified into 1 of 3 outcome groups: no bridging, partial bridging, and complete bridging. Diagnostic accuracy was evaluated using sensitivity, specificity, positive and negative predictive values, and receiver operator characteristic curves. Results Ten patients were diagnosed as complete bridging on CBCT, whereas 31 patients were diagnosed as complete bridging on lateral cephalogram. Although the lateral cephalogram detected all subjects with complete bridging, it incorrectly classified 12% of subjects. The percent agreement between both diagnostic methods was 55.68%, with a kappa statistic of 0.22 on the right sella turcica and 0.20 on the left sella turcica, indicating fair but statistically significant agreement. The overall accuracy of lateral cephalograms as a diagnostic modality in discriminating between no bridging and partial bridging was good as determined with the area under the curve values of 0.86 and 0.85 for right and left sides, respectively. Conclusions Although lateral cephalograms overestimate patients with complete bridging compared to CBCTs, they are a suitable screening modality for accurately suggesting complete sella turcica bridging and differentiating between patients with no bridging and partial bridging.

© International & American Associations for Dental Research 2021.Accurate segmentation of the jaw (i.e., mandible and maxilla) and the teeth in cone beam computed tomography (CBCT) scans is essential for orthodontic diagnosis and treatment planning. Although various (semi)automated methods have been proposed to segment the jaw or the teeth, there is still a lack of fully automated segmentation methods that can simultaneously segment both anatomic structures in CBCT scans (i.e., multiclass segmentation). In this study, we aimed to train and validate a mixed-scale dense (MS-D) convolutional neural network for multiclass segmentation of the jaw, the teeth, and the background in CBCT scans. Thirty CBCT scans were obtained from patients who had undergone orthodontic treatment. Gold standard segmentation labels were manually created by 4 dentists. As a benchmark, we also evaluated MS-D networks that segmented the jaw or the teeth (i.e., binary segmentation). All segmented CBCT scans were converted to virtual 3-dimensional (3D) models. The segmentation performance of all trained MS-D networks was assessed by the Dice similarity coefficient and surface deviation. The CBCT scans segmented by the MS-D network demonstrated a large overlap with the gold standard segmentations (Dice similarity coefficient: 0.934 ± 0.019, jaw; 0.945 ± 0.021, teeth). The MS-D network–based 3D models of the jaw and the teeth showed minor surface deviations when compared with the corresponding gold standard 3D models (0.390 ± 0.093 mm, jaw; 0.204 ± 0.061 mm, teeth). The MS-D network took approximately 25 s to segment 1 CBCT scan, whereas manual segmentation took about 5 h. This study showed that multiclass segmentation of jaw and teeth was accurate and its performance was comparable to binary segmentation. The MS-D network trained for multiclass segmentation would therefore make patient-specific orthodontic treatment more feasible by strongly reducing the time required to segment multiple anatomic structures in CBCT scans.

Cone beam computed tomography overcomes many of the limitations of traditional radiographic techniques and has become commonplace in dental practice. Pediatric patients are more likely to move during acquisition of the images and are susceptible to the harmful effects of ionising radiation. Therefore, justification for each individual and clinical scenario must occur before prescription of cone beam computed tomographs. There are clinical situations in which three-dimensional imaging is indicated as a first line investigation such as impacted canines and neighbouring root resorption, internal and external cervical resorption defects, virtual surgical planning for orthognathic surgery, autotransplantation analogues and assessment of TMJ anomalies. In these clinical situations, care should be taken to optimise the lowest radiation dose achievable for the pediatric patient whilst being indication-orientated and patient-specific.

Cone beam computed tomography (CBCT) is a diverse 3D x-ray imaging technique that has gained significant popularity in dental radiology in the last two decades. CBCT overcomes the limitations of traditional two-dimensional dental imaging and enables accurate depiction of multiplanar details of maxillofacial bony structures and surrounding soft tissues. In this review article, we provide an updated status on dental CBCT imaging and summarise the technical features of currently used CBCT scanner models, extending to recent developments in scanner technology, clinical aspects, and regulatory perspectives on dose optimisation, dosimetry, and diagnostic reference levels. We also consider the outlook of potential techniques along with issues that should be resolved in providing clinically more effective CBCT examinations that are optimised for the benefit of the patient.

Background. Dental caries is the localized destruction of dental hard tissues (enamel and dentine). Decayed, Missing, and Filled Teeth (DMFT) index is the most commonly used dental caries index. Thickness of the outermost part of the tooth called the enamel is determined by the rate of deposition of enamel proteins. Relative enamel thickness (RET) gives a measure of enamel thickness with respect to dentine. Dental caries is influenced by a genetically determined factor called dermatoglyphics (DG). As the genes responsible for RET and DG lie on the same chromosome and develop during the same time of intrauterine life, it is biologically plausible to correlate RET and DG. Aims. This study consists of two primary aims: (1) to assess RET using cone beam computed tomography images and correlate it with caries and (2) to correlate RET with DG. Materials and Methods. 148 dental subjects were assessed for DMFT caries score and were categorized as Group 1 with DMFT = 0 and Group 2 with DMFT ≥ 1 . Following this, their DG pattern was recorded digitally. The CBCT images of these subjects were assessed for RET, and the data were analyzed statistically. Results. Mean RET in our sample population is 18.45 (SD 3.79) while mean DMFT is 5.34 (SD 5.13). Mean RET in Group 1 subjects was 19.82 (SD 4.05) while that in the Group 2 was 17.68 (SD 3.43). RET and DMFT showed a statistically significant negative correlation ( p = 0.007 ). The “Single Loop” DG characteristic showed a statistically significant difference between males and females ( p = 0.031 ). The “Simple Arch” type of DG was positively correlated with RET. Conclusion. This is the first in vivo study to assess RET using CBCT images and correlate with DMFT and DG. RET is inversely related to DMFT while directly proportional to the “Simple arch” DG pattern. Males and females differed in their “Single Loop” DG characteristic.

Aim: To measure the inter-radicular spaces in both arches for miniscrew implant placement and to determine the most reliable sites using CBCT. Materials and Methods: A CBCT radiograph was taken for 75 subjects that met with inclusion criteria. They were divided into 3 categories- Hypodivergent, average, and hyperdivergent group. Images were calibrated by using software and printed as a film. Interradicular space on the right side of the jaw was measured in the sagittal plane after assuming the jaw to be symmetrical. Bucco-lingual and mesiodistal width were measured up to desired bone levels. Results: In vertical growth pattern, in posterior maxilla highest mesiodistal width between 2nd premolar and 1st molar at 7mm. In the mandible, it was between the 1st and 2nd molar at 11mm. In horizontal growth pattern, in posterior maxilla highest mesiodistal width between 1st and 2nd premolar, and mandible it was between 1st and 2nd molar at 11mm. In average growth pattern, in posterior maxilla highest mesiodistal width between 2nd premolar and 1st molar and 1st molar at 7mm. In the mandible, it was between the 1st and 2nd molar at 11mm. Conclusion: The importance of the relationship between the growth pattern and the availability of inter radicular space may aid the clinician in planning appropriate surgical sites for miniscrew implant placement. Keywords: Miniscrew, Implants, Interradicular bone anchorage

The process of deploying the two dimensional data in to the three dimensional format is three dimensional imaging. Now a days three dimensional imaging is developing as an emerging factor in the field of dentistry. Three dimensional imaging is useful in the field of orthodontics, to view the anatomy along with the morphology of the bone for desired tooth movement, it is useful in the field of prosthodontics to check or verify the bone morphology, exact height and width of the bone for the process placing implant, three dimensional imaging is quite useful in the field of endodontics along with oral surgery to view the anatomy of the root curvature, to confirm the presence of accessory canals to confirm the bony architectural defect in oral surgical procedures. So in present days three dimensional imaging plays an important role in diagnosis as well as treatment planning in the field of dentistry. Keywords: Cone beam computed tomography (CBCT).

Introduction: Oral submucous fibrosis (OSMF) is a chronic progressive, scarring disorder of oral cavity, which includes buccal mucosa, tongue, lips, anterior faucial pillars, soft palate, and oropharynx. Changes in soft palate morphology will start even before the OSMF, present itself clinically. These changes can lead to sleep apnea, difficulty in speech, swallowing & respiration. Various radiographs are good diagnostic aid to assess the soft palate and its morphology or any changes in morphology. Aim: To evaluate and compare soft palate morphology and dimensions in various stages of OSMF with control by radiographic evaluation. Materials and Methods : 60 patients were evaluated and compared for soft palate morphology, its length, width and angle by using lateral cephalogram and Cone beam computed tomography (CBCT). Results: Most common type of soft palate was found to be type 1 (leaf shaped) in both groups as well as by both radiographic techniques. Significant decrease in length and increase in width with increasing grades of OSMF group. As per p value CBCT gave more precise result. Conclusion: As the OSMF progresses soft palate becomes stout and bulky and significant changes occur in soft palate dimensions and are better evaluated by CBCT. As involvement of the soft palate is the earliest change to be noticed, radiographs should be used as one of the diagnostic aids in OSMF patients. Keywords : Oral submucous fibrosis, Radiographic evaluation, Morphology of soft palate.

Aim: To assess reliability in localization of hard and soft tissue landmarks of the upper airway and three-dimensional measurements of the upper airway based on these landmarks using CBCT images. Setting & Design: 22 full field of view (FOV) CBCT scan volumes were selected randomly and retrospectively made at the CBCT unit of Department of Oral Medicine and Radiology. Materials and Methods: Six anatomic landmarks that are relevant for upper airway analysiswere located and subsequently three-dimensional measurements (volume, minimum cross-sectional area (CSA), location of the CSA, anteroposterior and lateral dimensions of the CSA) in all planes (coronal, sagittal, axial) were performed based on these land marks by two observers, using Romexis software (4.2.0 R 10/13/15). Statistical Analysis used: Correlation analysis by Cronbach’s Alpha. Results: Interobserver reliability of the landmark localization was excellent (Internal consistency 0.97-0.99) and for the three-dimensional upper airway measurements were good (Internal consistency 0.62-0.99). Conclusion: The interobserver reliability of anatomical landmarks localization and three-dimensional measurements of the upper airway are good to excellent using Romexis software. Therefore, this methodology can be recommended for the upper airway analysis using CBCT images. Keywords: Upper airway, Cone beam computed tomography, Reliability.