Preoperative Cone Beam Computed Tomography Research Articles

Accuracy of 3-dimensional surgical guide for endodontic microsurgery with a new design concept: A cadaver study.

Despite the high success rate of endodontic microsurgery (EMS), it is difficult to suggest EMS as a general treatment option considering the difficulty of the procedure. A surgical guide has been proposed to overcome this problem. This study aimed to evaluate the stability of the surgical guide of a new design concept, as well as the accuracy of root resection, and to introduce the manufacturing method of the newly designed surgical guide. The experiment was conducted on 59 roots (9 in the maxillary and 50 in the mandibular region) of adult human cadavers. The surgical guide was designed using CAD/CAM design software based on cone-beam computed tomography (CBCT) images and optical scan files. Unlike conventional surgical guides, the surgical guide proposed herein was designed to act as a tooth-bone-supported removable appliance. Two different types of guides were prepared: the osteotomy guide (O guide) for separation of the cortical bone above the root tip with a trephine bur with an outer diameter of 6 mm and the root resection guide (R guide) for resection of the root tip with a trephine bur with an outer diameter of 4 mm. For stability evaluation, the guides were pressed at five predetermined locations after installation and checked for the presence of any movement. For accuracy evaluation, the length at which the root tip was cut was measured and examined by overlapping the preoperative and postoperative CBCT images. Of the 15 R guides, 14 were stably installed without mobility. For the R guide group, the root tip was resected with an average of 3.2 mm, showing better results than the no-guide group with an average of 4.0 mm. The newly designed surgical guide of this study can be applied more stably, enabling root resection to be performed more accurately and simply according to the preoperative plan than when performed without a guide.

Accuracy of robotic-assisted surgery for immediate implant placement in posterior teeth: a retrospective case series

BackgroundRobotic computer-assisted implant surgery (r-CAIS) is a revolutionary innovation in oral implantation; however, the clinical feasibility of r-CAIS for immediate implant placement (IIP) in posterior teeth has not been verified. Thus, this study aimed to evaluate the accuracy of r-CAIS for IIP in posterior tooth regions.MethodsPatients with posterior teeth to be extracted and indicated to undergo r-CAIS were evaluated. The patients had positioning markers installed in the oral cavity and underwent cone-beam computed tomography (CBCT). Subsequently, minimally invasive tooth extractions were performed, and an individualised surgical plan was generated in the robotic software. After marker registration, implantation surgery was performed by the robotic arm under the supervision and assistance of the surgeons. Finally, the deviations between the planned and placed implants were evaluated based on preoperative and postoperative CBCT data.ResultsA total of 12 patients were evaluated. No adverse events occurred during the surgery. The mean global coronal, global apical, and angular deviations were 0.46 ± 0.15 mm (95%CI:0.36 to 0.56 mm), 0.46 ± 0.14 mm (95%CI:0.37 to 0.54 mm), and 1.05 ± 0.55° (0.69 to 1.40°), respectively.ConclusionsUnder the limited conditions of this study, the r-CAIS exhibited high accuracy in posterior teeth IIP surgery. Further multicentre randomised controlled studies are required to confirm the feasibility of this technology.

Evaluation of Accessory Infraorbital Foramen with Cone Beam Computed Tomography

Objective: to assess the incidence, number and position of accessory infraorbital foramina (AIOF) according to cone beam computed tomography (CBCT).Material and methods. CBCT data from 156 patients who received dental care at a private medical center in Minsk (The Republic of Belarus) in 2018–2023 were analyzed.Results. In 29 (18.6%) patients, 38 AIOF were found. Unilateral doubling of the infraorbital foramen was more common than bilateral (21 patients compared to 8). In 1 case, the presence of two AIOF simultaneously on one side was noted. They were located medial and superior relative to the main infraorbital foramen at a distance 3.73–14.5 mm from it. In 2 of 13 patients with simultaneously visualized upper and lower jaws, an accessory mental foramen was found on the AIOF side. AIOF were more often identified on the left side (p<0.05); no gender differences in their occurrence were detected.Conclusion. The obtained results demonstrate a high frequency of infraorbital foramen doubling. To increase the effectiveness of surgical manipulations in the middle third of the face and prevent iatrogenic neurological complications, it is recommended to conduct a preoperative CBCT to clarify the localization of the main and accessory infraorbital foramina.

Comparative Evaluation of Platelet-rich Fibrin and Treated Dentin Matrix in Regenerative Endodontic Treatment of Nonvital Immature Permanent Teeth: A Randomized Clinical Trial.

Clinical and radiographic evaluation of the efficacy of platelet-rich fibrin (PRF) and treated dentin matrix (TDM) in regenerative endodontic treatment and periapical healing of nonvital immature permanent teeth with chronic apical periodontitis. Twenty-four children aged between 7 and 11 years, each presenting with a nonvital immature permanent upper central incisor, were selected. They were randomly allocated into two groups (n = 12), group I (PRF) and group II (TDM). Baseline clinical findings were recorded, and preoperative cone-beam computed tomography (CBCT) was taken. Follow-up was done clinically for 15 months at 3-month intervals (3, 6, 9, 12, and 15 months), and CBCT was taken at the end of the 15-month follow-up. Root length, apical diameter, radiographic root area (RRA), and size of the periapical lesion were quantitively assessed at the end of follow-up period and compared to the preoperative CBCT. Clinical success was 100% in both groups by the end of the follow-up period. Radiographically, after a 15-month follow-up, there was a significant increase in root length and RRA, and there was also a significant reduction in apical diameter and lesion size within each group (p < 0.05). However, there was no statistically significant difference between both groups regarding the mean percentage of increase in root length and mean percentage of reduction of apical diameter (p > 0.05). On the other hand, PRF showed more increase in RRA and more reduction in lesion size, with a statistically significant difference between both groups (p < 0.05). Both PRF and TDM were clinically successful. Platelet-rich fibrin showed better radiographic outcomes and periapical healing. Platelet-rich fibrin is a viable scaffold to aid further root development and resolution of periapical lesions of nonvital immature permanent teeth. Further studies with different forms of TDM are needed to assess the efficacy of TDM in regenerative endodontic treatment of nonvital immature permanent teeth. How to cite this article: Asal MA, Elkalla IH, Awad SM, et al. Comparative Evaluation of Platelet-rich Fibrin and Treated Dentin Matrix in Regenerative Endodontic Treatment of Nonvital Immature Permanent Teeth: A Randomized Clinical Trial. J Contemp Dent Pract 2024;25(6):563-574.

Maxillary advancement surgery with vertical component: Impact on the nasolabial aesthetics

The aim of this study is to evaluate the changes in nasolabial soft tissues following Le Fort I osteotomies, focusing on the impact of maxillary vertical repositioning.This retrospective study included 39 patients with a history of Le Fort 1 osteotomy between 2013 and 2021. Patients were grouped based on their maxillary movement into three categories: pure advancement (group A), advancement with impaction (group B), and advancement with downward repositioning (group C). Preoperative and postoperative CBCT (Cone Beam Computed Tomography) data were analyzed to measure the changes in nasolabial soft tissues. The current study utilized Mimics Suite 20.0 for measuring linear and angular variables. The evaluated variables included intercanthal distance, nasal dorsal length, tip protrusion, mouth width, alar width, upper lip height, nostril dimensions, and angles of nasolabial, alar base, and upper lip. Among them intercanthal distance, nasal dorsal length, or tip protrusion showed no statistical difference (p > 0,05). Mouth width, alar width, alar base angle were increased and upper lip angle was decreased significantly (p < 0.001). Changes in upper lip height and nasolabial angle differed among the groups of the study. While upper lip height increased significantly in groups A and C (p < 0.05), there was a slight decrease in Group B with no significance (p > 0.05). Nasolabial angle decrased significantly on Groups A and B (p < 0.05).The results of this study revealed changes in several soft tissue parameters, some of which occurred regardless of vertical repositioning of the maxilla. Within the limitations of the study, maxillary advancement surgery can affect the aesthetics of the nasolabial region and cause specific changes in related soft tissues. Understanding these changes is essential to establish realistic patient expectations and achieve optimal functional and aesthetic outcomes.

Key insights into antiresorptive drug use and osteonecrosis in osteoporotic patients undergoing tooth extractions: A clinical and CBCT assessment

SummaryThis study investigates the effects of antiresorptive drugs and risk factors for medication-related osteonecrosis of the jaws in osteoporotic patients undergoing tooth extraction. Among the findings, antiresorptive-treated patients had thicker lamina dura and longer healing times. Additionally, corticosteroid intake and multi-rooted teeth carried a higher osteonecrosis risk. Bone sequestrum indicated osteonecrosis.PurposeTo describe the effects of antiresorptive drugs (ARD) in the maxilla and mandible and risk factors for medication-related osteonecrosis of the jaws (MRONJ) in osteoporotic patients undergoing tooth extractions using clinical data and cone beam computed tomography (CBCT).MethodsThis retrospective cohort study collected clinical and CBCT data from 176 patients. The study group (n = 78; 224 extractions) received ARD treatment, underwent tooth extraction, and had a pre-operative CBCT. Additionally, age-, sex-, and tooth-matched controls were selected (n = 98; 227 extractions). Radiographic examinations were performed independently by three calibrated examiners. Statistical analysis included Chi-square, Fisher’s exact, Mann–Whitney U, and t-tests to contrast clinical and radiographic data between study and control, MRONJ + and MRONJ − , and bisphosphonate and denosumab patients/sites. Significance was set at p ≤ 0.05.ResultsFrom the study group, 4 patients (5%) and 5 sites (2%) developed MRONJ after tooth extraction. ARD-treated patients exhibited significantly more thickening of the lamina dura and a longer average mucosal healing time (4.4 weeks) than controls (2.6 weeks). In the study group, MRONJ risk significantly increased with corticosteroid intake and in multi-rooted teeth. No significant differences between bisphosphonates and denosumab use were seen in the tomographic features (p > 0.05). Lastly, bone sequestrum was exclusively observed in osteoporotic patients, who exhibited post-operative exposed bone or histological evidence of osteonecrosis.ConclusionOsteoporotic patients under ARD may exhibit thickening of the lamina dura and prolonged post-operative healing. Among these patients, multi-rooted teeth are at higher risk for MRONJ than single-rooted teeth. Sequester formation is a radiographic indicator of osteonecrosis.

Endodontic retreatment of a mesotaurodontic mandibular first molar with C-shaped configuration in a patient with multiple taurodonts: A case report and review of literature

Abstract Taurodontism is a dental anomaly characterized by an apical displacement of the pulp chamber floor, resulting in a large pulp chamber with short roots. It can be associated with certain syndromes and abnormalities, although it is common to occur as an isolated characteristic. This anomaly can occur along with other root canal system anomalies such as C-type configuration. The aim of this report is to present the successful endodontic management of a C-shaped mesotaurodontic mandibular molar and review the literature available on this matter. A 23-year-old Persian female was referred by her dental surgeon to complete the root canal treatment of her right mandibular first molar (#46). Clinical examination showed a temporized cavity with no response to pulpoperiapical tests or visible pocket depth while an elongated root trunk with slight periodontal ligament widening, incomplete obturation of the root canal system, and periapical radiolucency was evident on the intraoral radiograph. Cone-beam computed tomography (CBCT) revealed a taurodontic and type III C-shaped root canal configuration. With a diagnosis of previous treatment and asymptomatic apical periodontitis, the patient was scheduled for root canal retreatment. The same anomaly was discovered in other molar teeth on the panoramic radiograph taken before the primary treatment of tooth #46. At a 2-month follow-up session, the tooth was found asymptomatic clinically and radiographically. The past publications about the management of nonsyndromic taurodontic molars were also reviewed. The review of 29 similar articles showed that preoperative CBCT, magnification with illumination, along with active irrigation are helpful items in managing such cases.

A hybrid robotic system for zygomatic implant placement based on mixed reality navigation

BackgroundsZygomatic implant (ZI) placement surgery is a viable surgical option for patients with severe maxillary atrophy and insufficient residual maxillary bone. Still, it is difficult and risky due to the long path of ZI placement and the narrow field of vision. Dynamic navigation is a superior solution, but it presents challenges such as requiring operators to have advanced skills and experience. Moreover, the precision and stability of manual implantation remain inadequate. These issues are anticipated to be addressed by implementing robot-assisted surgery and achieved by introducing a mixed reality (MR) navigation-guided hybrid robotic system for ZI placement surgery. MethodsThis study utilized a hybrid robotic system to perform the ZI placement surgery. Our first step was to reconstruct a virtual 3D model from preoperative cone-beam CT (CBCT) images. We proposed a series of algorithms based on coordinate transformation, which includes image-phantom registration, HoloLens-tracker registration, drill-phantom calibration, and robot-implant calibration, to unify all objects within the same coordinate system. These algorithms enable real-time tracking of the surgical drill's position and orientation relative to the patient phantom. Subsequently, the surgical drill is directed to the entry position, and the planned implantation paths are superimposed on the patient phantom using HoloLens 2 for visualization. Finally, the hybrid robot system performs the processed of drilling, expansion, and placement of ZIs under the guidance of the MR navigation system. ResultsPhantom experiments of ZI placement were conducted using 10 patient phantoms, with a total of 40 ZIs inserted. Out of these, 20 were manually implanted, and the remaining 20 were robotically implanted. Comparisons between the actual implanted ZI paths and the preoperatively planned ZI paths showed that our MR navigation-guided hybrid robotic system achieved a coronal deviation of 0.887 ± 0.213 mm, an apical deviation of 1.201 ± 0.318 mm, and an angular deviation of 3.468 ± 0.339° This demonstrates significantly better accuracy and stability than manual implantation. ConclusionOur proposed hybrid robotic system enables automated ZI placement surgery guided by MR navigation, achieving greater accuracy and stability compared to manual operations in phantom experiments. Furthermore, this system is expected to apply to animal and cadaveric experiments, to get a good ready for clinical studies.

Real-Time Three-dimensional Dynamic Navigation for Post Space Preparation in Root Canal-Treated Teeth: An In vitro Study

IntroductionThe aim of this study was to investigate the feasibility of a real-time three-dimensional dynamic navigation system (3D-DNS) for post space preparation (PSP) in root canal-treated teeth and to compare the accuracy and efficiency of 3D-DNS to freehand (FH) for PSP. MethodsFifty-four maxillary molars were divided into two groups: 3D-DNS (n = 27) and FH group (n = 27). Cone beam computed tomography (CBCT) scans were taken preoperatively and postoperatively. The drilling path for the PSP was virtually planned in the preoperative CBCT scan in the X-guide software (X-Nav Technologies, Lansdale, PA). For the 3D-DNS group, the PSP drilling was conducted under dynamic navigation. The 3D deviations and angular deflections were calculated. The residual dentin thickness (RDT) was determined after PSP. The operation time and the total number of mishaps were recorded. Shapiro-Wilk, t-test or Mann-Whitney rank sum, weighted Cohen's kappa, and Fisher exact tests were used (P < .05). ResultsThe PSP was completed in all samples (54/54). The 3D-DNS was more accurate than the FH, with significantly fewer 3D deviations and angular deflections (all, P < .05). The 3D-DNS required less operating time than the FH (P < .05). For the 3D-DNS, no teeth had RDT < 1 mm, whereas 6/27 in the FH showed RDT < 1 mm after the PSP. There was no difference in the total number of mishaps (P > .05). ConclusionWithin the limitations of this in vitro study, the 3D-DNS is feasible for PSP. The 3D-DNS improved the accuracy and efficiency of PSP. The dynamic navigation system can potentially become a safe and reliable technology for PSP.

Incidence of Middle Mesial Canals in Mandibular Molars during Root Canal Treatment and Nonsurgical Retreatment

IntroductionLarge-scale clinical studies on the incidence of middle mesial canals (MMCs) in nonsurgical root canal treatment (RCT) and retreatment of mandibular molars are lacking. The primary aim of this observational study was to determine the incidence of MMCs in mandibular first and second molars that received RCT or nonsurgical retreatment (NSRetx). The secondary aim was to determine factors associated with incidence of MMCs. MethodsIncluded were 3018 mandibular molars that received RCT (n = 1624) or NSRetx (n = 1394) by 3 endodontists in a private practice. Demographic and procedural data were collected. Bivariate and multivariable (Poisson regression model) analyses were performed. ResultsIncidence of MMCs was 8.8% (n = 267). Although the bivariate analysis showed that NSRetx was significantly associated with incidence of MMCs, this association did not reach the threshold for statistical significance after controlling for all covariates (P = .07). Multivariable analysis on the entire cohort showed that incidence of MMCs was significantly associated with younger age (risk ratio [RR] = 1.62; 95% confidence interval [CI], 1.28–2.06), male gender (RR = 1.48; 95% CI, 1.18–1.85), preoperative cone-beam computed tomography (CBCT) (RR = 1.48; 95% CI, 1.17–1.89), and first molar (RR = 2.30; 95% CI:1.74–3.05). Subgroup multivariable analyses revealed that incidence of MMCs was associated with male gender only in the RCT group (RR = 2.26; 95% CI, 1.55–3.30) but not in the NSRetx group (RR = 1.11; 95% CI, 0.82, 1.50); and with preoperative CBCT only in the NSRetx group (RR = 1.78; 95% CI, 1.28, 2.50) but not in the RCT group (RR = 1.10; 95% CI, 0.71, 1.69). Associations with younger age and first molar remained unchanged. ConclusionsOverall incidence of MMCs was 8.8%. Incidence of MMCs was significantly higher in younger patients and in mandibular first molars but was not associated with the type of treatment.

Evaluating the Role of AI in Predicting the Success of Dental Implants Based on Preoperative CBCT Images: A Randomized Controlled Trial

ABSTRACT Background: Dental implant surgery has become a widely accepted method for replacing missing teeth. However, the success of dental implant procedures can be influenced by various factors, including the quality of preoperative planning and assessment. Cone beam computed tomography (CBCT) imaging provides valuable insights into a patient’s oral anatomy, but accurately predicting implant success remains a challenge Materials and Methods: In this randomized controlled trial (RCT), a cohort of 150 patients requiring dental implants was randomly divided into two groups: an artificial intelligence (AI)-assisted group and a traditional assessment group. Preoperative CBCT images of all patients were acquired and processed. The AI-assisted group utilized a machine learning model trained on historical data to assess implant success probability based on CBCT images, while the traditional assessment group relied on conventional methods and clinician expertise. Key parameters such as bone density, bone quality, and anatomical features were considered in the AI model. Results: After the completion of the study, the AI-assisted group demonstrated a significantly higher implant success rate, with 92% of implants successfully integrating into the bone compared to 78% in the traditional assessment group. The AI model showed an accuracy of 87% in predicting implant success, whereas traditional assessment methods achieved an accuracy of 71%. Additionally, the AI-assisted group had a lower rate of complications and required fewer postoperative interventions compared to the traditional assessment group Conclusion: The AI-assisted approach significantly improved implant success rates and reduced complications, underscoring the importance of incorporating AI into the dental implant planning process.

Mandibulada posterior bölgeye uygulanan implantlarda preoperatif kemik kalitesi ve primer stabilite arasındaki korelasyon

Aim: This study aimed to investigate preoperative bone quality obtained from the Hounsfield unit and fractal analysis scores in cone beam computed tomography (CBCT) sections and compare this value with primer stability derived from resonance frequency analysis scores soon after placement of implants in the mandibular posterior region. &#x0D; Material and Method: A total of 36 implant regions were examined retrospectively. Primary outcome variables include the Hounsfield unit, fractal analysis, and resonance frequency analysis scores soon after implant placement. Hounsfield unit and fractal analysis scores were calculated on the preoperative CBCT. &#x0D; Results: The mean Hounsfield unit, fractal analysis and resonance frequency analysis scores of all implants were 76.44, 0.65 and 67.44, respectively. No statistically significant correlation was found between the Hounsfield unit, fractal analysis and resonance frequency analysis scores (p&gt;0.05). Resonance frequency analysis scores (p=0.002) and Hounsfield unit scores (p=0.050) were significantly superior in males. Age was found to be related to resonance frequency analysis scores (r=0.445, p=0.007). &#x0D; Conclusion: The preoperative bone quality of alveolar bone measured from cone beam computed tomography by Hounsfield unit or fractal analysis may be insufficient to determine initial implant stability. Further studies are needed to investigate parameters related to the prediction of implant stability.

The utility of cone-beam computed tomography and multislice computed tomography scan for the evaluation of invasion versus erosion by mandibular squamous cell carcinoma as viewed on medical PACS

Introduction The degree of bone involvement in mandibular squamous cell carcinoma has a significant impact on surgical planning. The purpose of this study was to determine the utility of cone-beam computed tomography (CBCT) for the evaluation of invasion by mandibular squamous cell carcinoma. Methods A retrospective review was conducted to identify subjects treated for oral squamous cell carcinoma (OSCC). All subjects had OSCC adjacent or fixed to the mandible, received preoperative CBCT and multislice computed tomography scan (MSCT), and had resection specimens that included bone. Results Twenty-one subjects met the inclusion criteria. The sensitivity of CBCT was 100% (95% CI 0.75–1), the specificity was 75% (95% CI 0.35–0.97), the positive predictive value was 87% (95% CI 0.66–0.98), and the calculated test accuracy was 91%. The sensitivity of MSCT was 92% (95% CI 0.64–1), the specificity was 100% (95% CI 0.63–1), and the calculated test accuracy was 95%. Discussion CBCT provides meaningful data that may be useful in identifying bony involvement in patients with mandibular squamous cell carcinoma. The utility in delineating erosion versus invasion is limited.

Radiographic Criteria for Differential Diagnosis Between Vertical Root Fracture and Apical Periodontitis in Single-Rooted Endodontically Treated Premolars Using Cone-Beam Computed Tomography

IntroductionThis study explores the differences between the patterns of bone defects associated with vertical root fracture (VRF) and apical periodontitis (AP) in single-rooted endodontically treated premolars (SRETPs) based on cone-beam computed tomography (CBCT) data. MethodsEighty-four SRETPs were extracted and categorized into the VRF and AP groups. On preoperative CBCT images, the location of bone defects according to the root thirds in buccolingual and mesiodistal directions across the study groups were compared. ResultsThe majority of bone defects in the VRF group were longitudinal and combined, involving more than one root thirds in buccolingual and mesiodistal directions simultaneously. A uniform approach to comparing bone defects using the sites of periradicular area with bone loss as a comparison unit was developed. In the VRF group, bone loss sites in the middle and coronal thirds were detected more often and were located mainly buccolingually compared with the AP group (P < .001). ConclusionBone defects in the middle or middle and coronal root thirds in the buccolingual direction may be potential radiographic signs useful in differentiating between VRF and AP in SRETPs. The introduction of the uniform approach to assessment of bone loss patterns will give practitioners a single simple tool and improve the quality of endodontic treatment.

An evaluation of the sources and extent of error in the position of implants placed using 3D-printed stereolithographic surgical guides.

Introduction/Background. Errors can be introduced in implant placement when using stereolithographically manufactured fully limiting surgical guides due to various factors, such as discrepancies in designing and manufacturing of surgical guides (intrinsic error), built-in variations in design of mechanical components of guide systems and implant dimensions (inherent error) or due to placement error by the operator (operator error). Aim. The aim of this study was to evaluate influence of various factors on implant position when using these guides. Materials and Methods. Prosthetically-driven implant positions were planned with pre-operative cone beam computed tomography (CBCT) data and digital scans using a computer aided designing (CAD) software. Static guided implant surgery was performed under local anaesthesia using fully limiting mucosa-supported surgical guide. Pre-operative and post-operative CBCTs were superimposed using surgical sleeve as a reference to evaluate the placement error by operator (N=12). To evaluate intrinsic error, standard tessellation language (STL) files of the virtual design of the surgical guides and the STL file obtained after scanning the 3D printed stereolithographic surgical guides were superimposed. Inherent error was calculated using a geometric model. Results. Intrinsic error was observed to be a major contributing factor in angular deviation of implant, linear deviation observed at implant shoulder as well as at implant apex. Operator error was observed to be a major contributing factor for mean vertical deviation observed at apex of implant. Conclusion. This study showed that accuracy of implant placement was largely influenced by discrepancies introduced during designing and manufacturing of stereolithographic surgical guides as compared to other sources.

An evaluation of the sources and extent of error in the position of implants placed using 3D-printed stereolithographic surgical guides.

Introduction/Background. Errors can be introduced in implant placement when using stereolithographically manufactured fully limiting surgical guides due to various factors, such as discrepancies in designing and manufacturing of surgical guides (intrinsic error), built-in variations in design of mechanical components of guide systems and implant dimensions (inherent error) or due to placement error by the operator (operator error). Aim. The aim of this study was to evaluate influence of various factors on implant position when using these guides. Materials and Methods. Prosthetically-driven implant positions were planned with pre-operative cone beam computed tomography (CBCT) data and digital scans using a computer aided designing (CAD) software. Static guided implant surgery was performed under local anaesthesia using fully limiting mucosa-supported surgical guide. Pre-operative and post-operative CBCTs were superimposed using surgical sleeve as a reference to evaluate the placement error by operator (N=12). To evaluate intrinsic error, standard tessellation language (STL) files of the virtual design of the surgical guides and the STL file obtained after scanning the 3D printed stereolithographic surgical guides were superimposed. Inherent error was calculated using a geometric model. Results. Intrinsic error was observed to be a major contributing factor in angular deviation of implant, linear deviation observed at implant shoulder as well as at implant apex. Operator error was observed to be a major contributing factor for mean vertical deviation observed at apex of implant. Conclusion. This study showed that accuracy of implant placement was largely influenced by discrepancies introduced during designing and manufacturing of stereolithographic surgical guides as compared to other sources.

Comparative Determination of Working Length by Electronic Apex Locator, Digital Radiography, and Cone-beam Computed Tomography: An In vitro Study

Abstract Purpose: The aim of the present in vitro study is to evaluate and compare the working length determination by electronic apex locator, digital radiography radio visio graphy (RVG), and cone-beam computed tomography (CBCT). Materials and Methods: Sixty extracted teeth were collected, cleaned, and stored. Preoperative digital radiograph and CBCT scans of all the samples were taken. K-file was placed into root canal after access cavity preparation. According to the method used, different groups were made to determine the working length. Group I: Actual working length of each tooth was determined and kept as a control group. Group II: Each tooth working length was measured by electronic apex locator. Group III: Each tooth working length was measured by digital radiography (RVG). Group IV: Each tooth working length was measured by CBCT. Results: When compared with the actual working length by means of analysis of variance, the difference in mean working length calculated by electronic apex locator, RVG, and CBCT was found to be statistically significant (P = 0.001). Conclusions: Electronic apex locator is the most precise (96%) method for working length determination, followed by CBCT (94%). RVG was found to be a less accurate (93%) method in this study.

Nasal and maxillary sinus volume change in patients with obstructive sleep apnea after bimaxillary advancement surgery

The airway complex is modified by bimaxillary advancement surgery performed in patients suffering from obstructive sleep apnea (OSA). The aim of the present study is to analyse the volume of nasal and maxillary sinus after bimaxillary advancement surgery in patients suffering from OSA. The maxillary sinus and nasal complex of eighteen patients with OSA was measured through cone-beam computed tomography (CBCT) before and after they were treated with bimaxillary advancement surgery. Digital planning software was used to effectively measure the upper volume changes, as well as, statistical analysis of the results was performed.Methods Eighteen patients were diagnosed with OSA the severity of which was measured by the apnea hypopnea index and were selected and submitted to preoperative and postoperative CBCT scans. Afterwards, datasets were uploaded into therapeutic digital planning software (Dolphin Imaging) to measure the volume of the right and left maxillary sinus and nasal and maxillary sinus complex. Statistically analysis between preoperative and postoperative measures was performed by Student t-test statistical analysis.Results The paired t-test showed statistically significant volumetric reductions in the left maxillary sinus (p = 0.0004), right maxillary sinus (p < 0.0001) and nasal and maxillary sinus complex (p = 0.0009) after bimaxillary advancement surgery performed in patients suffering from OSA.Conclusion The results showed that bimaxillary advancement surgery reduces the maxillary sinus volume as well as, the fossa nasal and sinus complex volume.

Clinical Effect of Platelet-Rich Fibrin Combined with BIO-GENE Artificial Bone Meal in Bone Defects After Jaw Cyst Surgery.

To compare the clinical repair effects of leaving the defect empty and using Platelet-Rich Fibrin (PRF) combined with BIO-GENE artificial bone powder in patients with bone defects 6 months after jaw cystectomy. From June 2021 to June 2022, 70 patients who were admitted to the Department of Stomatology, Affiliated Hospital of Yanbian University, and were diagnosed with jaw cysts postoperatively were selected. All of the patients were divided into two groups according to random method, among which 35 patients who underwent cystectomy alone were recorded as group A, which served as blank control; 35 patients who underwent cystectomy and PRF combined with BIO-GENE artificial bone meal repaired bone defects during the same period were recorded as group B. 3D Slicer 5.0.3 software was used to reconstruct Cone Beam Computed Tomography (CBCT) after operation. In this study, the preoperative and postoperative CBCT data of the patients were analyzed using 3D Slicer 5.0.3 software in DICOM format to calculate the cleft volume before surgery and the newly formed bone volume after surgery. The osteogenesis rate was measured based on these calculations.The bone formation percentage in the bone defect area was recorded at 6 months, and the clinical curative effects of the two groups were compared. After 6 months of surgery, the patients showed varying degrees of restoration in the jaw cyst area.The osteogenesis rate at 6 months in group A was 76.06±13.38%, while group B had a rate of 92.87±5.72%.The CBCT values in group B were higher than those in group A at 6 months post-surgery (P<0.05), t=-6.84.Group A and Group B showed a statistically significant difference. Compared with simple cystectomy, PRF combined with BIO-GENE artificial bone powder has a better effect on the speed of bone repair after cystectomy within 6 months and provides more favorable effects for the repair of postoperative dentition defects, and provides support to repair teeth after defects such as dental implants.

Evaluation of the buccal bone thickness in the anterior maxillary region using cone-beam computed tomography

Aim: This study aimed to analyze the buccal plate thickness of maxillary anterior teeth using cone-beam computed tomography (CBCT) images. Methodology: This study involved a retrospective analysis of CBCT images from 104 randomly selected patients aged 20–50 years who had not experienced loss of their maxillary central and lateral incisors and canine teeth. The bone thicknesses of six anterior maxillary teeth were measured at 1 mm, 3 mm, and 5 mm distances apical to the alveolar bone crest (ABC) and between the cemento-enamel junction (CEJ) and ABC for six anterior maxillary teeth. The association between buccal bone plate width and distance from the CEJ to the ABC was examined across genders and among different age groups. Results: The mean buccal bone thicknesses were 1.13 mm, 1.22 mm, and 1.04 mm at distances of 1 mm, 3 mm, and 5 mm, respectively. The mean distance from the CEJ to the ABC was 2.09 mm. A negative correlation was observed between age and the distance from the CEJ to the ABC. No correlation was found between buccal bone thickness and gender, and a negative correlation existed between age and buccal bone thickness. Women displayed a significantly lower distance from the CEJ to the ABC compared to men, and a negative correlation between buccal bone thickness and distance from the CEJ to the ABC was present across all tooth groups. Conclusion: This study revealed that the bone width in the maxillary anterior region was remarkably thin. Therefore, achieving the minimum bone thickness of 2 mm necessary for optimal aesthetic and functional outcomes is seldom feasible in this area. Considering these findings, additional research utilizing larger patient cohorts is essential to fully comprehend how age and gender affect buccal bone thickness and CEJ-ABC distance. Additionally, utilizing preoperative CBCT for radiographic analysis to identify risk factors and select the appropriate treatment approach is strongly recommended. How to cite this article: Sağlıklı A, İpek F. Evaluation of the buccal bone thickness in the anterior maxillary region using cone-beam computed tomography. Int Dent Res 2023;13(S1):1-10. https://doi.org/10.5577/idr.2023.vol13.s1.1 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.