Postoperative Cone-beam Computed Tomography Scans Research Articles

Influence of the Vertek aiming device on the surgical accuracy of computer-assisted drilling of the equine distal sesamoid bone-An experimental cadaveric study.

To determine the effect of the Vertek aiming device (VAD) on the surgical accuracy of navigated drilling of the distal sesamoid bone (DSB). Experimental cadaveric study. A total of 30 paired equine cadaveric limbs from 15 horses. Each specimen was placed in a purpose-built frame (PBF). Preoperative cone beam computed tomography (CBCT) images were acquired with an imaging unit coupled with a surgical navigation system. In the DSB of each specimen, a 4.5 mm glide hole and a 3.2 mm thread hole were drilled under navigation guidance, to simulate drilling for the repair of a mid-sagittal DSB fracture. In the VAD group navigated drilling was assisted by using the VAD. In the free-hand drilling group navigated drilling was performed without the VAD. Pre-and postoperative CBCT scans were merged and surgical accuracy aberrations (SAA) between the planned drill corridor and the created bone tunnel were measured. Descriptive statistics and repeated-measures analyses of variance (rep.-meas. ANOVA) were performed to compare SAA measurements between the study groups. The SAA measurements ranged from 0 to 2.9 mm in the free-hand group and from 0 to 2.8 mm in the VAD group. The median overall SAA was lower in the VAD group than in the free-hand navigated group (0.6 mm ± [0.5-0.7] vs. 0.8 mm ± [0.7-1], rep.-meas. ANOVA p = .007). The additional use of the VAD in the described set-up for navigated drilling significantly improved surgical accuracy. The combined use of the VAD and PBF may help improve surgical accuracy in navigated lag screw repair of DSB fractures.

Assessment of the application of a novel three-dimension printing individualized titanium mesh in alveolar bone augmentation: A retrospective study.

To assess the clinical and radiographic outcomes of alveolar ridge augmentation using a novel three-dimensional printed individualized titanium mesh (3D-PITM) for guided bone regeneration (GBR). Preoperative cone-beam computed tomography (CBCT) was used to evaluate alveolar ridge defects, followed by augmentation with high-porosity 3D-PITM featuring circular and spindle-shaped pores. Postoperative CBCT scans were taken immediately and after 6 months of healing. These scans were compared with preoperative scans to calculate changes in bone volume, height, and width, along with the corresponding resorption rates. A statistical analysis of the results was then conducted. A total of 21 patients participated in the study, involving alveolar ridge augmentation at 38 implant sites. After 6 months of healing, the average bone augmentation volume of 21 patients remained at 489.71 ± 252.53 mm3, with a resorption rate of 16.05% ± 8.07%. For 38 implant sites, the average vertical bone increment was 3.63 ± 2.29 mm, with a resorption rate of 17.55% ± 15.10%. The horizontal bone increment at the designed implant platform was 4.43 ± 1.85 mm, with a resorption rate of 25.26% ± 15.73%. The horizontal bone increment 2 mm below the platform was 5.50 ± 2.48 mm, with a resorption rate of 16.03% ± 9.57%. The main complication was exposure to 3D-PITM, which occurred at a rate of 15.79%. The novel 3D-PITM used in GBR resulted in predictable bone augmentation. Moderate over-augmentation in the design, proper soft tissue management, and rigorous follow-ups are beneficial for reducing the graft resorption and the incidence of exposure.

The Role of Bone Tacks in Sinus Floor Lift Surgery: A Single-Center Experience.

Background: Maxillar atrophy is a prevalent condition associated with diminished bone volume, which precludes the conventional placement of dental implants. Sinus floor lift is a surgical procedure that aims to address this atrophy through the insertion of a graft within the sinus cavity. A multitude of techniques have been documented in the international literature for the management of the sinus bone window, though each approach has its own set of advantages and disadvantages. Methods: The present study is a retrospective analysis of traditional sinus floor lift surgery, comparing the outcomes of two surgical approaches: placement of a collagen membrane over the maxillary lateral bone window with or without bone tacks. The study enrolled a total of 48 consecutive patients. Twenty-four patients underwent sinus floor lift surgery, with the placement of a collagen membrane over the maxillary lateral bone window without bone tacks (control group). The remaining 24 patients underwent the same procedure, but with bone tacks (study group). All patients received an amoxicillin 875 mg + clavulanic acid 125 mg administration for six days and underwent Cone Beam Computed Tomography (CBCT) before the sinus floor lift surgery and six months later before the implant surgery. The parameters measured on the preoperative Cone Beam Computed Tomography (CBCT) scan included residual bone, the preoperative thickness of the lateral bone in the center, and the distance between the lateral wall and the medial wall of the sinus. Only the bone height increment was measured on the postoperative CBCT scan. Postoperative complications and the visual analogue scale (VAS) score were also recorded. A statistical analysis was performed, and the correlation between the parameters was evaluated using Pearson's correlation coefficient. A comparison of the mean of the parameters between the treatment group and the control group was conducted using the t-test. Results and Conclusions: The study group was found to have superior outcomes in terms of bone height increment (p = 0.001) and VAS after 7 days (p = 0.11) compared to the control group. The novel application of bone tacks on the collagen membrane over the bone window following sinus elevation surgery was associated with superior outcomes in terms of bone height and reduced pain at seven days, as measured by the VAS, with no postoperative complications.

Comparative evaluation of remaining dentin thickness using single file, two file, and multiple rotary file system - An in vitro CBCT study.

Endodontic success hinges on a multifactorial interplay, with meticulous canal shaping, proper disinfection, and three-dimensional obturation being paramount. Among these factors, the amount of dentin remaining after instrumentation directly influences the biomechanical resilience and longevity of the tooth. This study aims to evaluate the impact of various rotary instrumentation systems, including single-file, two-file, and multiple-file configurations, on the remaining dentin thickness (RDT) following canal preparation. This was an in vitro study, original research article. Sixty mandibular premolar human extracted teeth were decoronated at the cementoenamel junction with a diamond disc. Samples were randomly assigned to three groups using a simple random sampling technique (n = 60). Group I - Single-file system (One Curve, MicroMega) (n = 20), Group II - Two-file systems (2Shape, MicroMega) (n = 20), and Group III - Multiple-file system (Hero Gold, MicroMega) (n = 20). Preoperative cone-beam computed tomography (CBCT) scans were obtained after the sample was mounted on a modeling wax sheet. The biomechanical preparation of canals followed the manufacturer's protocols for every system. Postoperative CBCT scans were obtained. Pre- and postoperative scans were compared at standardized depths (4 mm, 7 mm, and 11 mm) within the canals (coronal, middle, and apical thirds), allowing for a comprehensive assessment of RDT throughout the canal. According to one-way ANOVA, the highest mean was seen in Group I, followed by Group II and Group III. Hence, a statistically significant difference was found between all the groups. Post hoc Tukey's test was done for intergroup comparison. A single-file system preserved more dentin with less aggressive cutting compared to two-file and multiple-file systems.

Accuracy of immediate anterior implantation using static and robotic computer-assisted implant surgery: A retrospective study

ObjectivesTo investigate the accuracy of immediate anterior implantation using static computer-assisted implant surgery (s-CAIS) and robotic computer-assisted implant surgery (r-CAIS). Materials and methodsOne hundred and six implants were immediately inserted in the anterior zone of 69 patients using a freehand technique, s-CAIS or r-CAIS. Postoperative cone-beam computed tomography scans were matched with preoperative plans to evaluate the deviations between the planned and placed implant positions. ResultsThe global coronal deviations in the freehand, s-CAIS, and r-CAIS groups were 1.29 ± 0.52 mm, 1.01 ± 0.41 mm, and 0.62 ± 0.28 mm, respectively. Significant differences were observed in the r-CAIS group compared to both the s-CAIS group and the freehand group (p < 0.05). However, no significant differences were found between the s-CAIS group and the freehand group (p > 0.05). The global apical deviations in the freehand, s-CAIS and r-CAIS groups were 1.78 ± 0.59 mm, 1.24 ± 0.52 mm and 0.65 ± 0.27 mm, respectively, while the angular deviations in the freehand, s-CAIS and r-CAIS groups were 6.46 ± 2.21°, 2.94 ± 1.71° and 1.46 ± 0.57°, respectively. Significant differences were observed in both the global apical deviations and angular deviations among the three groups (p < 0.05). ConclusionsThe accuracy of immediate anterior implantation with r-CAIS was better than that with s-CAIS. This difference is attributed to better control of the coronal, vertical and axial errors during r-CAIS. Clinical significanceThis study provides significant evidence to support the use of r-CAIS as a potential alternative in immediate anterior implantation.

Comparison of the Accuracy and Efficiency of Two Dynamic Navigation System Workflow for Fiber-post Removal: Small versus Large Field-of-view Registration Workflows

IntroductionThis study investigates the feasibility of a dynamic navigation system (DNS) small field of view workflow (DNS-SFOVw) for fiber-post removal and compares its accuracy and efficiency to the conventional large field of view workflow (DNS-LFOVw). MethodsFifty-six extracted human maxillary molars were divided into DNS-SFOVw (n = 28) and DNS-LFOVw (n = 28). The palatal canal was restored with an intraradicular RelyX fiber post and luted with RelyX Unicem; a core buildup was used. Teeth were mounted in a 3D-printed surgical jaw. A preoperative cone-beam computed tomography (CBCT) scan was taken with a 40 × 40 mm FOV for the DNS-SFOVw and a single arch CBCT scan for the DNS-LFOVw. The drilling entry point, trajectory, angle, and depth were planned in the X-guide software. The DNS registration method for the DNS-SFOVw was virtual-based registration on teeth, and the marker point-based method was used for the DNS-LFOVw. The fiber posts were drilled out under DNS guidance. A postoperative CBCT scan was taken. Three-dimensional deviations, angular deflection, number of mishaps, registration, and total operation time were calculated. ResultsThe DNS-SFOVw was as accurate as DNS-LFOVw (P > .05). The DNS-LFOVw registration time was less than DNS-SFOVw (P < .05). There was no difference in the number of mishaps (P > .05). Both DNS-SFOVw and DNS-LFOVw were time-efficient, with DNS-LFOVw taking less total operational time (P < .05). ConclusionWithin the limitations of this in-vitro study, the DNS-SFOVw was as accurate as the DNS-LFOVw for fiberpost removal. Both DNS-LFOVw and DNS-SFOVw were time-efficient in removing fiber-posts.

Accuracy comparison of single- and double-sleeve endodontic guides for fiber post removal

BackgroundThis study aimed to assess the accuracy of two different endodontic guides for fiber post removal.MethodsIn this in vitro study, 54 maxillary canine fiber posts were mounted on 36 maxillary stone casts; 18 teeth were mounted unilaterally, and 36 teeth were mounted bilaterally. Static endodontic guides were fabricated according to baseline cone-beam computed tomography (CBCT) and intraoral optical scans using Blue Sky software. In the single-sleeve endodontic guides group (SSG), two anterior and two posterior teeth were included in a 5-unit guide. In the double-sleeve endodontic guides group (DSG) group, the guide was passed through the midline to include both canine teeth and extended by 2 teeth posterior to the canine teeth bilaterally (a 10-unit guide). After drilling, postoperative CBCT scans were taken and superimposed on the virtually designed path, and the maximum coronal deviation (MCD) at the marginal entry point of the tooth, maximum apical deviation (MAD) at 10 mm apical to the tooth margin, and maximum angular deflection (MAnD) of the drill were calculated.ResultsThe mean MCD, MAD, and MAnD were 0.34 mm, 0.6 mm, and 2.32 degrees, respectively, in the SSG and 0.31 mm, 0.7 mm, and 2.37 degrees, respectively, in the DSG. The two groups were not significantly different from each other in terms of MCD (P = 0.573), MAD (P = 0.290), or MAnD (P = 0.896).ConclusionsThe accuracies of the two techniques, the extended double sleeve guide and the single sleeve guide, were comparable and thus DSG may be used for removal of fiber posts in adjacent or distant teeth.

Influence of augmented reality technique on the accuracy of autotransplanted teeth in surgically created sockets

BackgroundThe objective of the present study was to evaluate the reliability of an augmented reality drilling approach and a freehand drilling technique for the autotransplantation of single-rooted teeth. Materials and methodsForty samples were assigned to the following surgical techniques for drilling guidance of the artificial sockets: A. augmented reality technique (AR) (n = 20) and B. conventional free-hand technique (FT) (n = 20). Then, two models with 10 teeth each were submitted to a preoperative cone-beam computed tomography (CBCT) scan and a digital impression by a 3D intraoral scan. Afterwards, the autotrasplanted teeth were planned in a 3D dental implant planning software and transferred to the augmented reality device. Then, a postoperative CBCT scan was performed. Data sets from postoperative CBCT scans were aligned to the planning in the 3D implant planning software to analize the coronal, apical and angular deviations. Student’s t-test and Mann–Whitney non-parametric statistical analysis were used to analyze the results.ResultsNo statistically significant differences were shown at coronal (p = 0.123) and angular (p = 0.340) level; however, apical deviations between AR and FT study groups (p = 0.008) were statistically significant different.ConclusionThe augmented reality appliance provides higher accuracy in the positioning of single-root autotransplanted teeth compared to the conventional free-hand technique.

Cortical Block Grafting Successfully Augments Alveolar Cleft Sites for Dental Implant Placement

BackgroundSupplemental bone grafting is regularly required before dental implant placement in patients with cleft lip and palate (CLP). PurposeThe study purpose was to measure and compare implant osseointegration and changes in graft dimensions following lateral incisor onlay cortical bone grafting in CLP and non-CLP patients. Study design, setting, sampleRetrospective cohort study composed of patients who presented to Boston Children’s Hospital and underwent autogenous onlay cortical block bone grafting at lateral incisor sites from 2015 through 2023. Patients were excluded if the cone beam computed tomography (CBCT) quality was insufficient for accurate measurements. Predictor variableThe predictor variable was CLP status coded as CLP or non-CLP. Main outcome variableThe primary outcome variable was successful implant osseointegration confirmed by a torque of 35 N/cm or more after 3 months of implant healing. Secondary outcomes were change in bone width between pre- and post-operative CBCT scans at lateral incisor sites and the need for additional bone augmentation prior to or during implant placement. CovariatesCovariates were age, sex, cleft location, and time from bone graft to postoperative CBCT and implant placement. AnalysesData analyses were performed using T-tests, Fisher’s Exact Tests, Mann-Whitney U Tests, and Pearson’s correlation. P<0.05 was considered statistically significant. ResultsA total of 22 subjects (16 with CLP) were evaluated. The mean age at the time of graft was 19.3 ± 2.4 years with 52.6% males. Implants osseointegrated at 20 of 22 lateral incisor sites (one CLP failure, one non-CLP failure). There was significant change in bone width after grafting for patients with CLP (p<0.001). Patients with CLP experienced a 3.32 (± 1.80) mm and 2.99 (± 1.61) mm increase in bone width at two different levels. Patients with CLP achieved greater boney changes near the alveolar crest than non-cleft patients (p=0.008) but the change was not significantly different more apically (p=0.86). One subject with CLP required additional grafting during implant placement. Conclusions and RelevanceCortical block onlay bone grafting is a predictable technique to augment lateral incisor sites in patients with cleft lip and palate for placement of a dental implant.

Comparative Analysis of the Efficacy of Various Retreatment File Systems in the Removal of Gutta-Percha in Retreatment Cases and Time Taken During the Procedure: An In Vitro Cone Beam CT Study.

Background Removing gutta-percha manually can be a challenging task, especially when addressing densely packed root-filling material, particularly in cases where resin-based sealers are employed for obturation. The use of nickel-titanium (NiTi) rotary instruments not only effectively shapes the root canal but also efficiently removes the endodontic filling from the curved canal during retreatment. Hence, incorporating rotary NiTi instruments in retreatment cases can alleviate fatigue for both patients and operators. Objectives This study aims to compare the efficacy of Neo-Endo retreatment files, R-Endo retreatment files, and K and H files in the removal of endodontic filling material. Additionally, the remnants of gutta-percha in root canals are evaluated using cone beam computed tomography (CBCT). Materials and methods A total of 60 extracted first maxillary molar teeth were selected for this study. Canal preparation was conducted using the step-back method up to an apical size of 40 K-file. The obturation process involved the use of gutta-percha points and AH Plus sealer in a lateral compaction technique. Post-operative CBCT scans were taken. The samples were randomly divided according to the retreatment files used: group I included Neo-Endo retreatment files, group II included R-Endo retreatment files, and group III included conventional K-files and Hedstroem files (H-Files). The retreatment procedure was considered complete when the last instrument easily reached the working-length range and was physically clean. A stopwatch was used to record the time taken by each file to remove the obturating material. T1 represented the total time (including irrigation and change of file) required to reach the apex, while T2 indicated the complete removal of materials from the canal with the last instrument. The overall time recorded (TT) was calculated as T1 + T2. The removal process was analyzed with CBCT scans. Results The Neo-Endo retreatment files removed the filling materials better and more quickly than the other files. Conclusions Despite the presence of residual filling material in all samples, the Neo-Endo retreatment files left the least amount of residual filling material and achieved the shortest completion time.

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.

Quantifying bone healing after mandibular displacement in orthognathic surgery

Impaired bony healing following bilateral sagittal split osteotomy (BSSO) is a major unmet medical need for affected patients, and rare occurrences can hinder the identification of underlying risk factors. We hypothesised that osseous union following BSSO can be quantified using volumetric analysis, and we aimed to identify the risk factors for impaired bone healing. The percentage change in bony volume was measured in orthognathic patients following BSSO using two consecutive postoperative cone-beam computed tomography scans. Patients’ characteristics and treatment parameters were documented, and correlation and regression analyses of these variables performed. Thirty-six patients (23 men and 13 women) with a mean (SD) age of 33.28 (11.86) years were included. The gap site (lingual versus buccal) (p < 0.01) had a significant impact on the change in volume. Age (p = 0.06) showed a trend towards significance. Initial width of the osteotomy gap, sex, and indication for surgery did not influence osseous healing. Increased age at surgery and the side of the buccal osteotomy are independent risk factors for impaired osseous healing following BSSO.

Accuracy of autonomous robotic surgery for dental implant placement in fully edentulous patients: A retrospective case series study.

This study evaluated the accuracy of dental implant placement using the robotic computer-assisted implant surgery (r-CAIS) technology in fully edentulous patients. Fully edentulous and terminal dentition patients were enrolled for r-CAIS technology. Based on the cone-beam computed tomography (CBCT) examination, a customized positioning marker and a preoperative surgical plan were created before surgery. During the implant surgery, the implant osteotomy and placement were automatically performed using an autonomous robotic surgery system under the surgeon's supervision. A postoperative CBCT scan was used to determine the discrepancies between the planned and placed implants. Ten patients with 59 implants underwent autonomous robotic surgery. No adverse surgical events occurred. The deviations of global coronal, global apical, and angular were 0.67 ± 0.37 mm (95% CI: 0.58-0.77 mm), 0.69 ± 0.37 mm (95% CI: 0.59-0.78 mm), and 1.27° ± 0.59° (95% CI: 1.42°-1.11°), respectively. The autonomous r-CAIS technology proved an accurate surgical approach for implant placement in fully edentulous patients due to the control of the angular deviation. Autonomous robotic surgery seems promising as an accurate technology for treating fully edentulous patients. However, further trials are required to provide more hard clinical evidence.

Guided endodontics versus conventional access cavity preparation: an ex vivo comparative study of substance loss

BackgroundTo compare the outcomes of conventional access cavity preparation (CONV) versus guided endodontics (GE) for access cavity preparation in anterior teeth with pulp canal calcification (PCC) regarding root canal detection, substance loss, procedural time, and need for additional radiographs.MethodsExtracted, sound human teeth with PCC (n = 108) were matched in pairs, divided into two groups and used to produce 18 models. An independent endodontist and a general dentist performed access cavity preparation under simulated clinical conditions on nine models each (54 teeth). The endodontist used the conventional technique and the general dentist GE. Time needed to access the root canals and the number of additional radiographs were recorded. Pre- and postoperative cone-beam computed tomography scans were obtained to measure substance loss. Statistical significance was tested by examining the overlap of 95% confidence intervals (CIs) between the groups.ResultsAll root canals were successfully accessed by both methods. There were no significant differences in substance loss (CI: CONV 15.9–29.6 mm3 vs. GE 17.6-27.5mm3) or procedural time (CI: CONV 163.3-248.5 s vs. GE 231.9-326.8 s). However, 31 additional radiographs were required for GE compared to none for CONV.ConclusionsFor access cavity preparation in teeth with PCC, both CONV by a specialist and GE by a general dentist produce good results in terms of substance loss and time requirements.

Does the Protrusion of Corticobasal Implants in the Maxillary Sinuses Affect Sinus Health? A Retrospective Study.

The aim of this retrospective study is to investigate the effect of corticobasal implant penetration in the nasal and maxillary sinuses on sinus health and implant survival rate in cases of severely atrophid ridges. This retrospective study was conducted on thirty patients with 172 implants who underwent corticobasal implant treatment between 2014 and 2018. Implants were divided into two groups according to the penetration depths (Group A, <4 mm; Group B, 4 mm). Inclusion criteria for the study included: (A) patients with severe maxillary ridge resorption with an immediately loaded corticobasal implant-supported prosthesis that showed implant protrusion inside the maxillary sinus on cone-beam computed tomography (CBCT); and (B) patients with a preoperative and postoperative follow-up CBCT scan using the same standard technique and machine. (C) Patients without any history of sinusitis before implant insertion patients who fulfilled the inclusion criteria were recalled for follow-up. The presence of sinus complications was clinically assessed according to the clinical practice guidelines for adult sinusitis of the American Academy of Otolaryngology-Head and Neck Surgery and Radiologically using CBCT. Moreover, patient satisfaction was evaluated using yes-or-no questions. The result was statistically analyzed using Fisher's Exact test. Despite the differences in implant penetration depths, no clinical signs of sinusitis were evident in any patient. One patient presented with transient epistaxis after the surgery, and 2 patients with nine implants revealed nonsignificant thickening of the sinus membrane radiologically (p = 0.055). All implants showed optimum bone-implant contact with a 100% survival rate. A significant relationship was reported between the thickness of the membrane and the patient's gender, hypertension, and smoking habits. (p = 0.001*, p = 0.002*, and p = 0.034*, respectively). Penetration of corticobasal implants in the maxillary sinus did not compromise the health of the maxillary sinus or implant survival rate. Limited posterior maxillary bony support and maxillary sinus pneumatization present challenges in implant dentistry and increase the possibility of implant protrusion inside the maxillary and nasal cavities. Hence, studying the effect of this protrusion on the maxillary sinuses' health and implant survival is highly significant.

Computer-assisted surgery for placing toggle constructs across the coxofemoral joints of small equids using a minimally invasive approach-A proof-of-concept cadaveric study.

To develop a minimally invasive technique for placing a toggle construct across the coxofemoral joint of small equids using computer-assisted surgery. Experimental cadaveric study. Three pilot specimens: One donkey, one Shetland pony and one Warmblood foal. Six main study specimens: Three Shetland ponies, one American Miniature Horse, one Warmblood foal and one donkey. Experimental surgeries were performed on both coxofemoral joints of each cadaver. Using a minimally invasive surgical approach, 5.5 mm bone canals were drilled through the femur and acetabulum, traversing the coxofemoral joint. Intraoperative guidance was provided by a cone-beam computed tomography (CBCT)-coupled surgical navigation system. A toggle construct was introduced through the bone canals. Surgical accuracy aberrations (SAA) were measured at the femoral entry and exit points and at the acetabular entry point on merged pre- and postoperative CBCT scans. The coxofemoral joint was assessed for articular cartilage damage by gross dissection. A toggle construct was placed across all 18 coxofemoral joints. The overall median SAA in the main study was 2.8 mm (range: 0.4-8.0 mm). No cartilage damage was found in the cadaveric specimens of the main study. The described technique allowed for the placement of a toggle construct across the coxofemoral joint of small equid cadaveric specimens without prior coxofemoral luxation. This technique may serve as an option for surgical stabilization of coxofemoral joints in small equids. Further biomechanical investigations are required to assess optimal implant positioning and toggle constructs.

Cone-Beam Computed Tomography Evaluation of Rotary MM Files vs Manual K Files in Primary Molars: An In Vitro Study.

Rotary instrumentation in pediatric dentistry is an emerging concept, thus this study was performed to evaluate the remaining dentine thickness (RDT), canal transportation, centering ability, quality of obturation using cone-beam computed tomography (CBCT), and the time efficiency of rotary versus manual instrumentation in mandibular second primary molars. Forty mandibular primary second molars (160 canals) were randomly and equally allocated to four groups. Instrumentation was done using K files in groups I and II; in each group, the obturation was done by two different obturation techniques; incremental technique and disposable syringe technique, respectively. MM rotary files (Innovative Material and Devices, Inc. [IMD], Shanghai, China) were used in groups III and IV; in each group, the obturation was done by incremental technique and disposable syringe technique. Preoperative and postoperative CBCT scans were performed and evaluated for the RDT, centering ability, canal transportation, and the canal filling quality, which was assessed as (underfill, optimal fill, and overfill). Instrumentation time was recorded for groups I and II collectively (manual instrumentation), and groups II and III collectively (rotary instrumentation). Statistical analysis was done using Chi-square, ANOVA, and post hoc Tukey tests, at p < 0.05). The MM rotary file removed a significantly less amount of dentine at all levels specifically at the middle section (p = 0.003). The canal transportation was significantly higher in the manual group at the cervical level (p = 0.022). In all sections, the rotary group had significantly higher values of centering ratio than the manual group (p < 0.05), which means a lower deviation of rotary instruments. For both types of files, there was no significant difference between different obturation techniques (p > 0.05). Instrumentation time was significantly lower in the rotary group (p < 0.001). Regarding the dentine removal and the shaping ability of MM files acceptable results were obtained; however, no significant difference between the different obturation techniques. Notable time efficiency was reported in the rotary files as well. The use of rotary files resulted in better conservation of tooth structure, better canal centering, and obturation quality as well as less canal transportation and less instrumentation time compared to manual K files.

Application of Real-time Augmented Reality-guided Osteotomy and Apex Location in Endodontic Microsurgery: A Surgical Simulation Study Based on 3D-printed Alveolar Bone Model

IntroductionAugmented reality (AR) is a novel visualization technique in which pregenerated virtual 3D content is superimposed on surgical sites. This study aimed to validate the viability of AR-guided endodontic microsurgery (ARG) and compare the changes in objective and subjective outcomes of surgical simulation using ARG and freehand (FH) endodontic microsurgery on customized 3D-printed models. MethodsWe created and printed a customized 3D alveolar bone model with artificial periapical lesions (APLs) based on cone-beam computed tomography. Eight models with 96 APLs were equally divided into ARG and FH groups. We planned surgical trajectories on rescanned printed models. Four inexperienced residents (IRs) performed ARG and FH on the models and completed pre and intraoperative confidence questionnaires for the subjective outcome. Postoperative cone-beam computed tomography scans of the models were reconstructed and analyzed, and all procedures were timed. We used pairwise Wilcoxon rank sum tests to compare objective outcomes. Kruskal–Wallis tests and post hoc pairwise Wilcoxon rank sum tests were used to compare subjective outcomes. ResultsCompared to the FH group, the ARG group significantly reduced deviation of the volume of bone removal, root-end resection, and deviation of bevel angle, with improved confidence of the IRs (P < .05); it also significantly increased surgical time and volume of unremoved APL (P < .05). ConclusionsWe customized an APL model through 3D printing and developed and validated a low-cost AR application framework, based on free AR software, for endodontic microsurgery. ARG allowed IRs to perform more conservative and precise surgical procedures with enhanced confidence.

Guided Access through Ceramic Crowns with Fiberglass Post Removal in Lower Molars: An In Vitro Study

This in vitro study evaluated the accuracy of guided endodontics for the removal of intraradicular fiberglass posts from posterior mandibular teeth and the influence of the operator’s experience in this procedure. Forty root-filled mandibular first molars with an intraradicular fiberglass post were mounted onto 20 mandibular models. Guides for access were made following surface scanning and cone-beam computed tomography (CBCT) using CoDiagnostix software. The models were randomly divided between two operators (n = 20). One was an inexperienced dental surgeon (IN), and the other was a dentist experienced in the guided technique (EX). A postoperative CBCT scan was superimposed on the initial planning, and the means were calculated for the angle and for 3D deviation. The 95% confidence interval (CI) was calculated, and differences between groups were assessed by a t-test. The mean deviation angle was 2.54° (0–5.85°) for IN and 1.55° (0–2.85°) for EX. The mean 3D deviation was 0.44 mm (0.14–0.73 mm) for IN and 0.33 mm (0.11–0.76 mm) for EX. The means of the angle and 3D deviation were significantly different (p = 0.008 and p = 0.049). Guided endodontics was influenced by the operator and allowed access for removing intraradicular fiberglass posts with minimal deviation and greater accuracy for an experienced operator compared with an inexperienced one.

Accuracy of computer-aided static and dynamic navigation systems in the placement of zygomatic dental implants

BackgroundZygomatic implants are widely used in the rehabilitation of severely atrophic maxillae, but implant placement is not without risks, and it can potentially cause damage to related anatomical structures. The aim of this study was to perform a comparative analysis of the accuracy of static navigation systems in placing zygomatic dental implants in comparison to dynamic navigation systems.MethodsSixty zygomatic dental implants were randomly allocated to one of three study groups, categorized by which implant placement strategy was used: A: computer-aided static navigation system (n = 20) (GI); B: computer-aided dynamic navigation system (n = 20) (NI); or C: free-hand technique (n = 20) (FHI). For the computer-aided study groups, a preoperative cone-beam computed tomography (CBCT) scan of the existing situation was performed in order to plan the approach to be used during surgery. Four zygomatic dental implants were inserted in each of fifteen polyurethane stereolithographic models (n = 15), with a postoperative CBCT scan taken after the intervention. The pre- and postoperative CBCT scans were then uploaded to a software program used in dental implantology to analyze the angular deviations, apical end point, and coronal entry point. Student’s t-test was used to analyze the results.ResultsThe results found statistically significant differences in apical end-point deviations between the FHI and NI (p = 0.0053) and FHI and GI (p = 0.0004) groups. There were also statistically significant differences between the angular deviations of the FHI and GI groups (p = 0.0043).ConclusionsThe manual free-hand technique may enable more accurate placement of zygomatic dental implants than computer-assisted surgical techniques due to the different learning curves required for each zygomatic dental implant placement techniques.