Preoperative Cone Beam Computed Tomography Research Articles

A novel mixed reality-guided dental implant placement navigation system based on virtual-actual registration

BackgroundsThe key to successful dental implant surgery is to place the implants accurately along the pre-operative planned paths. The application of surgical navigation systems can significantly improve the safety and accuracy of implantation. However, the frequent shift of the views of the surgeon between the surgical site and the computer screen causes troubles, which is expected to be solved by the introduction of mixed-reality technology through the wearing of HoloLens devices by enabling the alignment of the virtual three-dimensional (3D) image with the actual surgical site in the same field of view. MethodsThis study utilized mixed reality technology to enhance dental implant surgery navigation. Our first step was reconstructing a virtual 3D model from pre-operative cone-beam CT (CBCT) images. We then obtained the relative position between objects using the navigation device and HoloLens camera. Via the algorithms of virtual-actual registration, the transformation matrixes between the HoloLens devices and the navigation tracker were acquired through the HoloLens-tracker registration, and the transformation matrixes between the virtual model and the patient phantom through the image-phantom registration. In addition, the algorithm of surgical drill calibration assisted in acquiring transformation matrixes between the surgical drill and the patient phantom. These algorithms allow real-time tracking of the surgical drill's location and orientation relative to the patient phantom under the navigation device. With the aid of the HoloLens 2, virtual 3D images and actual patient phantoms can be aligned accurately, providing surgeons with a clear visualization of the implant path. ResultsPhantom experiments were conducted using 30 patient phantoms, with a total of 102 dental implants inserted. Comparisons between the actual implant paths and the pre-operatively planned implant paths showed that our system achieved a coronal deviation of 1.507 ± 0.155 mm, an apical deviation of 1.542 ± 0.143 mm, and an angular deviation of 3.468 ± 0.339°. The deviation was not significantly different from that of the navigation-guided dental implant placement but better than the freehand dental implant placement. ConclusionOur proposed system realizes the integration of the pre-operative planned dental implant paths and the patient phantom, which helps surgeons achieve adequate accuracy in traditional dental implant surgery. Furthermore, this system is expected to be applicable to animal and cadaveric experiments in further studies.

Treatment-Related Factors Affecting the Success of Endodontic Microsurgery and the Influence of GTR on Radiographic Healing-A Cone-Beam Computed Tomography Study.

The primary objective of this retrospective study was to assess the correlation between treatment-related factors (resection angle, depth of retrograde filling, length of resected root and use of guided tissue regeneration-GTR) evaluated using cone-beam computed tomography (CBCT) scans and the treatment outcomes of endodontic microsurgery (EMS). The secondary purpose of this research was to evaluate the influence of the GTR technique on the radiographic healing state, taking into account the initial parameters of periapical lesions. In 161 cases, the local factors (volume of a lesion, bone destruction pattern, presence/absence of cortical bone destruction) were measured using preoperative CBCT images before undergoing EMS. At least one year after surgery, the outcome of EMS was classified as a success or a failure (based on radiographic and clinical criteria). Using postoperative CBCT, treatment-related factors (resection angle, depth of retrograde filling, and length of resected root) were measured. Additionally, the status of radiographic healing was evaluated (in accordance with modified PENN 3D criteria). Eighteen cases (11.18%) were classified as failures, and 143 were classified as successes (88.82%). Univariate analysis showed that there was no statistically significant influence of treatment-related factors on the healing outcome of EMS. An exact Fischer's test showed the significant impact of GTR on radiographic healing (P < 0.001) in apical lesions (P < 0.001), lesions with a volume between 100 mm3 and 450 mm3 (P < 0.009) and over 450 mm3 (P < 0.001), lesions with the destruction of one plate (P < 0.001), and lesions with the destruction of two plates (through and through) (P = 0.022). The use of GTR in apical lesions, lesions with volumes over 100 mm3, and lesions with the destruction of at least one plate is significantly associated with better radiographic healing.

Fractal analysis of the mandible cortical bone: correlation among fractal dimension values obtained by two processing methods from periapical radiograph and micro-computed tomography with cone-beam computed tomography.

The objectives of the present study were to assess Fractal Dimension (FD) values in the mandible cortical bone obtained from digital periapical radiographs (DPR), high-resolution microtomography (µCT), and cone-beam computed tomography (CBCT), by two processing methods: binarization (FD.b) and grayscale-based method (FD.f) and, finally, to identify the correlation among these values with other micro-architectural parameters. For this, a prospective study was conducted on 18 healthy individuals (mean age 23 ± 2.4years old) who underwent third molar extraction. Pre-operative CBCT scans were conducted, bone fragments were removed from the retro-molar region, and DPR and µCT were performed on those bone samples. FD.b and FD.f values were calculated using three parasagittal sections for CBCT, one image for DPR, and three sections for µCT. The 3D bone microarchitecture was analyzed in µCT (voxel size: 19µm). As a result, FD.b mean values of 1.55 ± 0.02 and 1.80 ± 0.01 were obtained for CBCT and µCT, respectively. Furthermore, FD.f mean values of 1.22 ± 0.12 for DPR, 0.99 ± 0.04 for CBCT, and 1.30 ± 0.07 for µCT were obtained. Both FD.b and FD.f values showed a good agreement. FD.f was negatively correlated with the standard deviation of the mean gray value (p = 0.003) for DPR and intra-cortical bone surface (p = 0.02) for µCT. In conclusion, image processing with or without binarization revealed different values for FD, although showing agreement. The grayscale-based method retrieved FD values correlated with the gray levels and the cortical porous network, which means that FD can be a valuable index for mandibular cortical bone evaluation. FD is associated with mineralization and microarchitecture. Nevertheless, there was no correlation between FD values obtained from low- (DPR) and high-resolution (µCT) X-ray modalities with FD obtained from the in vivo CBCT.

Autologous concentrated growth factor mediated accelerated bone healing in root-end microsurgery: A multicenter randomized clinical trial

IntroductionConcentrated growth factor (CGF) is a new-generation autologous platelet concentrate that promotes tissue regeneration and has anti-inflammatory properties. This randomized multicenter trial aimed to evaluate the effects of CGF on bone healing in combination with root-end microsurgery. MethodsHealthy adult patients indicated for root-end microsurgery were randomly assigned to either the CGF or control (no CGF implantation) groups. CGF was implanted into the bone cavity after root-end filling with mineral trioxide aggregate. Clinical and periapical radiographic evaluations were conducted at 1, 3, 6, and 12 months postoperatively, with follow-up cone-beam computed tomography (CBCT) at 6 months. The lesion volume reduction rate was calculated based on data from the preoperative and follow-up CBCT images. ResultsA total of 24 patients were enrolled. The treatment success rate was 91.7% and 83.3% on 12-month periapical radiography and 6-month CBCT, respectively, without a significant difference between the two groups. The lesion volume reduction rate in the CGF group (75.6%) was significantly higher than that in the control (61.0%) group. ConclusionsAutologous CGF in conjunction with root-end microsurgery accelerated lesion reduction as observed on CBCT. Administering autologous blood products to stimulate healing in addition to removing the source of infection appears to be a promising treatment option for root-end microsurgery.

Novel Three-Dimensional and Non-Invasive Diagnostic Approach for Distinction between Odontogenic Keratocysts and Ameloblastomas.

Aim of this study was to demonstrate the diagnostic ability to differentiate odontogenic keratocysts (OKCs) from ameloblastomas (AMs) based on computed tomography (CT) or cone beam computed tomography (CBCT) scans. Preoperative CT and CBCT scans from 2004 to 2019 of OKCs and AMs were analyzed in 51 participants. Lesions were three-dimensionally (3D) assessed and Hounsfield units (HU) as well as gray scale values (GSV) were quantified. Calculated HU spectra were compared within the same imaging modalities using unpaired t-tests and correlated with participants characteristics by calculating Pearsons correlation coefficients. Within the CT scans, AMs had highly significantly higher HU values compared to OKCs (43.52 HU and 19.79 HU, respectively; p < 0.0001). Analogous, within the CBCT scans, AMs had significantly higher GSV compared to OKCs (-413.76 HU and -564.76 HU, respectively; p = 0.0376). These findings were independent from participants' gender and age, anatomical site, and lesion size, indicating that the HU- and GSV-based difference reflects an individual configuration of the lesion. HU and GSV spectra calculated from CT and CBCT scans can be used to discriminate between OKCs and AMs. This diagnostic approach represents a faster and non-invasive option for preoperative diagnosis of such entities and has potential to facilitate therapeutic decision making.

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.

Cone-beam computed tomographic analysis of maxillary sinus septa among Yemeni population: a cross-sectional study

BackgroundMaxillary sinus septa increase perforation risk of Schneiderian membrane during the sinus floor elevation (SFE). Cone Beam Computed Tomography (CBCT) allows for a more precise assessment of the septal position; thus, preoperative CBCT analysis is substantial to avoid possible complications. This study aims to investigate the 3D characteristics of the maxillary sinus septa based on CBCT images. To our knowledge, no study reported the CBCT-based investigation for the sinus septa among Yemeni population.Materials and methodsThis is a retrospective cross-sectional analysis of 880 sinus CBCT images 440 patients. The septa prevalence, locations, orientations, morphology, and associated factors were analyzed. The effect of age, gender, and dental status on the sinus septa and the relationship between sinus membrane pathology and sinus septa were also analyzed. Anatomage (Invivo version 6) was used for CBCT images analysis. Descriptive and analytical statistics were performed, and a P-value < 0.05 was significantly considered.ResultsThe maxillary sinus septa were found among 63.9% of patients and 47% of sinuses. The average septa height was 5.2 mm. 15.7% of patients had septa in the right maxilla, 18% in the left, and 30.2% in both. Gender, age, and dental condition had no influence on the presence of septa, and septa presence did not influence sinus membrane pathology. Many septa originated from the floor (54.5%), located in the middle (43%), with coronal orientation (66%) and complete configuration (58.2%).ConclusionBased on our findings, the septa prevalence, locations, orientations, and morphology were significant and equivalent to the highest recorded in the literature yet. Thus, when sinus floor elevation is planned, CBCT imaging of the maxillary sinus is recommended for safe dental implantation.

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.

Comparative Evaluation of Root Canal Transportation and Centering Ability in Curved Mesiobuccal Canals of Mandibular First Molars after Instrumentation with Different File Systems-An In vitro Study.

To assess the canal transportation and centering ability in the mandibular first molars' curved mesiobuccal canals after instrumentation with file systems XP endo Shaper, self-adjusting File (SAF), Hyflex EDM, Pro Taper NEXT, WaveOne Gold, and K files with the help of Cone-Beam Computed Tomography (CBCT). Ninety recently extracted mandibular first molars with mesiobuccal roots that had a 25-30 degree canal curvature were assessed. Following preoperative CBCT scans, teeth were allocated randomly to six experimental groups of fifteen. After preparation with XP endo Shaper, SAF, Hyflex EDM, Pro Taper Next, WaveOne Gold, and K files, post-instrumentation scans were taken using same parameters as pre operative scans. At 3 mm, 6 mm, and 9 mm from the apex, samples were assessed for canal transportation and centering ratio. Apical transportation was least for XP endo Shaper as compared to other groups except SAF and the results were statistically significant. K file showed the highest apical transportation toward the lateral wall of the root canal. XP endo Shaper was better in maintaining centering ability of middle and apical third of canal and SAF was better in maintaining centering ability of coronal third. In root canal preparation, least apical transportation and better centering ability with XP endo Shaper than other file systems compared. K file showed the highest transportation.

D21. Failure Rates Based on Alveolar Cleft Size: An Analysis of the Critical Size Defect for rhBMP-2/DBM and Iliac Crest in Alveolar Bone Grafting

PURPOSE: Iliac crest bone graft (ICBG) is the standard of alveolar bone grafting (ABG). However, recombinant human bone morphogenetic protein(rhBMP-2) with demineralized bone matrix (DBM) has been proposed as an alternative. We aim to identify the critical size defect of failure rates for ICBG and rhBMP-2/DBM. METHODS: A retrospective review evaluated patients undergoing ABG from 2016-2022. Patients with genetic syndromes, bilateral clefts, and missing postoperative cone beam computed tomography (CBCT) were excluded. The 3-dimensional volumetric defect sizes were calculated using preoperative CBCT scans. The primary outcome was bony bridge formation based on postoperative imaging. Logistic regression was used to model graft failure rates and identify the maximal point, which defined the critical point. RESULTS: Among 148 patients screened, 62 were included who underwent ABG (ICBG: n=28; rhBMP-2/DBM: n=34). There was no significant difference in bridge formation between graft types. The critical point in failure rate was calculated to be 829.3mm3 and 857.8mm3 for rhBMP-2/DBM and ICBG, respectively. Upon Fisher-exact analysis, there were increased bridge failures in clefts greater than the critical point for both ICBG (p<0.001) and rhBMP-2/DBM (p=0.005). The critical point did not vary between graft types (p=0.772) CONCLUSION: Our findings identified a higher probability of graft failure beyond the predicted critical size defect for each respective bone graft. Clinicians can better counsel families of patients with larger defects with a higher probability of treatment failure using either ICBG or rhBMP-2/DBM.

Associations between cortical bone-to-implant contact and microstructure derived from CBCT and implant primary stability.

To evaluate the associations between the cortical bone-to-implant contact (CBIC), bone microstructure derived from cone-beam computed tomography (CBCT), and the primary stability of the implant. Twenty-two patients with 65 implants were enrolled in this study. The peak insertion torque values (ITVs) were measured during implant insertion, and the implant stability quotient (ISQ) values were measured immediately after implant placement and 3months after surgery. The profiles of the peri-implant bone structure were outlined using the volumetric reconstruction of the CBCTs and superimposition of the virtual models, and the features of CBIC and bone microstructure parameters were measured. The linear mixed effects model and generalized estimating equation were used to explore the predictors for implant primary stability. The average ITV, baseline, and secondary ISQ values were 31.44 ± 6.54 N·cm, 73.34 ± 7.39, and 80.32 ± 4.58, respectively. Statistically significant correlations were found between ITV and surface area of CBIC (r= .340, p= .006), bone volume fraction (r= .294, p= .017), and bone surface fraction (r= -.278, p= .039). Implants with buccolingual CBIC had a higher ITV than implants without CBIC (p= .016). None of the parameters were associated with baseline and secondary ISQ values in generalized estimating equation analysis (all p> .05). Within the limitations of the study, preoperative CBCT measurements might enable the prediction of ITV and therefore of implant primary stability values.

Individual "alveolar phenotype" limits dimensions of lateral bone augmentation.

Alveolar ridge resorption following tooth extraction often renders a lateral bone augmentation inevitable. Some patients, however, suffer from severe early (during graft healing, Eres ) and/or late (during follow-up, Lres ) graft resorption. We explored the hypothesis that the "individual phenotypic dimensions" may partially explain the degree of such resorptions. Patients who underwent a guided bone regeneration (GBR) procedure were screened for inclusion according to the following criteria: (1) a relatively symmetrical maxillary arch; (2) an intact contra-lateral alveolar bone dimension; (3) the availability of a pre-operative cone-beam CT (CBCT); (4) a CBCT taken immediately after GBR, and (5) at least one CBCT scan ≥6 months after surgery. CBCT scans from different timepoints were registered and imported into the Mimics software (Materialise, Leuven, Belgium). Bone dimensions of the contra-lateral site of the augmentation, representing the "individual phenotypical dimension (IPD) of the alveolar crest", were superimposed on the augmented site and registered accordingly. As such, Eres and Lres could be measured over time, in relation to the IPD (in two dimensions; per millimetre apically from the alveolar crest, in the centre of the GBR), as well as in three dimensions (the entire GBR, 2 mm away from the mesial, distal, and apical border for standardization). A total of 17 patients (23 augmented sites) were included. After Eres , the outline of the augmentation was in general located ±1 mm outside the IPD, but ≥1.5 years after GBR, it further moved towards the IPD (85% within 0.5 mm distance). Within the limitations of this study, the results indicate that the dimensions of a lateral bone augmentation are defined by the "individual phenotypic bone boundaries" of the patient.

Clinical efficacy of 1% metformin gel around conventionally placed dental implants: A 9-month follow-up study.

The study aimed to compare the clinical and radiographic outcomes of bone volume, density, and crestal bone levels in conventionally placed dental implants with and without local application of 1% metformin (MF) gel using cone-beam computed tomography (CBCT) at 9 months. Twenty implants were placed in 18 individuals, randomly divided into 2 groups where Group A received a local application of 1% MF gel along with implant placement. In contrast, Group B received implant placement alone. After thorough clinical examination and preoperative CBCTs, implants were placed under aseptic conditions. Patients were recalled at 3 and 9 months after surgery. Implants were functionally loaded by the end of 3rd month. Soft-tissue parameters such as modified plaque index and modified sulcular bleeding index were recorded along with CBCT evaluation to assess the crestal bone loss, bone density measurement, and bone volume, postoperatively. Fisher's extract test, independent and paired t-test, and Bonferroni analysis were used to determine statistical significance with P ≤ 0.05. There was no discernible difference between the groups regarding soft-tissue parameters, bone density, and crestal bone levels. However, comparing bone volume between the test and control groups at 9 months was statistically significant. The test group with 1% MF gel showed increased bone volume around the implant. The data obtained were strong enough to suggest that 1% MF gel administered locally can increase peri-implant bone volume, possibly due to its additional property favoring osteoblastic stimulation and proliferation.

Variables That Affect the Ability to Find the Second Mesiobuccal Root Canals in Maxillary Molars.

The study aimed to investigate the influence of various factors on the localization of the second mesiobuccal (MB2) canal in maxillary molars, a commonly missed canal during endodontic treatment. A comprehensive assessment of maxillary molars treated over three years with a dental operative microscope was conducted. Factors such as patient gender, age, tooth type, pulp status, pre-operative cone-beam computed tomography (CBCT), and treatment modality were examined. Statistical analyses included chi-square and multiple logistic regression. Among 333 treated maxillary molars, the MB2 canal was identified in 60.1%. The prevalence of MB2 canals was significantly higher in the first molars (72.3%) compared to the second molars (40.2%; P=0.001). Multiple logistic regression models showed that gender, tooth type, and treatment modality emerged as significant determinants of MB2 canal localization: males [odds ratio 3.01(CI 95%:1.71-5.32), P<0.001], first molar tooth [odds ratio 4.26 (CI 95%:2.53-7.18), P<0.001] and secondary endodontic treatment [odds ratio 0.06 (CI 95%: 0.004-0.890), P<0.04]. Patient gender, tooth type, and treatment modality play pivotal roles in the identification of the MB2 canal. Additionally, the availability of pre-operative CBCT imaging was associated with a heightened ability to locate the MB2 canal.

Factors affecting the reduction rate of odontogenic cysts after decompression based on 3-dimensional volumetric analysis.

This study aimed to investigate the potential factors that could affect the reduction rate of odontogenic cysts following decompression using cone-beam computed tomography (CBCT) for 3-dimensional volumetric analysis. The study sample consisted of CBCT images of 41 individuals who underwent decompression of odontogenic cysts at the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Chulalongkorn University, between 2010 and 2022. Preoperative and postoperative CBCT results were collected, and a volumetric analysis was conducted to evaluate the differences in the reduction rate and the percentage of volume reduction of cystic lesions based on different parameters. Correlations between these parameters were analyzed to determine associations. In this study, the average time of decompression for odontogenic cysts was 316 days. Males demonstrated a higher reduction rate than females (P<0.05). The reduction rate was directly proportional to initial cyst volume, with higher reduction rates for cysts with large initial volume than those with small initial volume (P<0.05). Spearman's rank correlation coefficient indicated a weak positive correlation between the initial cyst volume and the duration of decompression. Additionally, a strong positive correlation was observed between the initial volume and the reduction rate. Knowledge of the reduction rate of odontogenic cysts is vital for surgeons to evaluate the duration of decompression before enucleation and to determine a definitive treatment plan. Sex and initial lesion volume had significant effects on the reduction rate.

Evaluation of interorifice distance in permanent mandibular first molar with middle mesial canal in Bengaluru city, Karnataka: A cone-beam computed tomography study

Aim: Analysis of interorifice distance (IOD) between mesiobuccal and mesiolingual canals in the presence of middle mesial canal (MMC) variants in mandibular first permanent molar (MFPM) in an Indian subpopulation. To categorically assess the prevalence of MMC variants considering variation in factors of age and gender. Methods: Analysis of preoperative cone-beam computed tomography (CBCT) images was performed on 256 MFPM. MMCs were classified as fin, confluent, or independent as per the classification given by Pomeranz et al. (1981). Orthogonal slices from pulpal floor to 4 mm below were used to measure mean IOD using the CBCT software tool. Data were subjected to descriptive statistics. The Chi-square test was used for further analysis. Results: The prevalence of independent MMC was 4.7% (n = 12), confluent 14.6% (n = 37), and fin 8.7% (n = 22). The mean IOD measured for fin variant was 3.12 ± 0.512 mm, 3.31 ± 0.402 mm for confluence variant, 3.72 ± 0.493 mm for independent MMC, and 3.36 mm ± 0.579 for two-canal variant. Significant association (P = 0.001) was observed between age, gender, and overall detection of MMC, wherein the presence of fin (8.6%) and confluent (12.9%) configurations was higher (P = 0.003) in individuals ≤40 years. There was increased IOD in females (17.9%) than males (10.3%), for confluent, independent, and two-canal configuration (P = 0.04; =0.01, =0.001). Decreased IOD was observed in individuals >40 years for two-canal configurations (P = 0.05). Conclusion: Preoperative CBCT assessment of MFPM aids in the detection of MMC. According to the results of this study, individuals aged ≤40 years have shown higher prevalence of fin and confluent variants. Increased IOD was seen in females for confluent, independent, and two-canal configurations. Decreased IOD was seen in individuals aged >40 years having two-canal configuration. Thus, root canal complexities vary with age and gender, and should be taken into consideration before endodontic treatment.

Comparative evaluation of the effect of conventional and truss access cavities on remaining dentin thickness, canal transportation, and canal centering ability in mandibular molars using cone-beam computed tomography

Aim: To evaluate and compare the effect of conventional and truss access cavity preparations on remaining dentin thickness (RDT), canal transportation, and centering ability in mandibular molars using cone-beam computed tomography (CBCT). Methods: Ethical approval was obtained before the commencement of the study. Thirty extracted mandibular molars were selected, disinfected, and stored in normal saline. Preoperative CBCT scans were taken for all the samples and randomly divided into two groups. (n = 15). Group A; Conventional access preparation group; Group B; Truss access preparation group. Cleaning and shaping were performed with the mesiobuccal canal of all the samples. Postoperative CBCT scans were compared with preoperative CBCT scans to evaluate the RDT, canal transportation, and canal centering ability in mandibular molar with conventional and truss access cavity preparation. Results: Data obtained from CBCT were analyzed by independent sample t-test with the P < 0.05 and found that RDT was higher in Group A as compared to Group B at the 3 and 9 mm levels, whereas it was higher in Group B at 6 mm level in both the mesial and distal side, but it was statistically insignificant at 3, 6, and 9 mm level. Canal transportation was higher in Group B than in Group A, but it was statistically insignificant at 6 and 9 mm levels but statistically significant at 3 mm. Canal centering ability was higher in Group A than in Group B, but it was not statistically significant at 3, 6, and 9 mm levels. Conclusion: Regarding RDT and canal centering ability, there is no statistically significant difference at all levels. Both groups present a statistically significant difference at 3 mm from the apex when comparing canal transportation. This suggests that conventional access cavity preparation is better than truss access preparation to maintain original canal anatomy.

Preoperative CBCT Guided Bone Regeneration Combined with Concentrated Growth Factor Applied in the Implantation of Maxillary Teeth with Insufficient Bone Mass.

It was to explore the application effect of cone beam computed tomography (CBCT) guided bone regeneration (GBR) combined with concentrated growth factor (CGF) in the implantation of maxillary teeth with insufficient bone mass. 78 patients with single maxillary anterior tooth loss and labial alveolar defects in Dazhong Stomatological Hospital were retrospectively analyzed and randomly divided into groups A and B. Both groups were treated with surgical methods of GBR at the same time of implantation. Group A: CGF fibrin fluid and Bio-Oss bone powder, covered with CGF membrane on the surface to guide bone regeneration. Group B: Bio-Oss bone powder was implanted and covered with Heal All collagen biofilm. The horizontal bone width, keratinized gingival width, bone plate thickness, implant margin results, and alveolar ridge width were analyzed at 3 and 6 months before and after the operation in both groups. 6 months after the operation, the difference in the indexes between the two groups was evident; and in group A, the indexes had an obvious difference in contrast with those before operation; the healing rate of soft tissue was 100% in group A and 80% in group B, which was significantly different (P < 0.05). Preoperative CBCT GBR combined with CGF can promote the bone formation content of guided regeneration of bone defects in the maxillary teeth region.

Assessment and Correlation of Variation in Lingual Cortical Plate Thickness with Different Angulations of Impacted Mandibular Third Molar Using Cone Beam Computed Tomography in North Indian Population.

The extraction of impacted mandibular third molar is associated with various types of intraoperative and postoperative complications, one of them is injury to lingual nerve. The present study aims to assess and correlate the variation in lingual cortical plate thickness with different angulations and determine the topographic relationship between the root apex of impacted mandibular third molar and lingual cortical plate using Cone Beam Computed Tomography (CBCT). This prospective cohort study enrolled 140 patients with impacted mandibular third molars who underwent preoperative CBCT imaging. The CBCT images were used to evaluate the outcome variables such as lingual cortical plate thickness and topographical relationship between root apex of impacted mandibular third molar and lingual cortical plate. The predictor variables included age, gender, inclination of third molar, mesiodistal angle, buccolingual angle and lingual plate morphology. The temporary lingual nerve paresthesia was reported by 1 patient (0.71%) out of 140 patients. The lingual bone in distoangular and vertical impacted third molar was found to be 1.20 times thicker than mesioangular and horizontal teeth. Lingual bone thinning at mid-root level was observed in maximum number of cases with mesioangular teeth (68.5%), whereas horizontal impacted teeth showed lingual bone thinning (90.9%) at root apex level. The mean buccolingual angle of impacted mandibular third molar was found to be significantly associated with lingual bone perforation (p value = 0.0258). The morphology of lingual plate was observed as undercut type (37.14%) followed by slanted (36.43%), parallel (19.29%) and round type (7.14%). Increase in buccolingual angle of impacted mandibular third molar decreases lingual bone thickness which is the natural barrier for protecting injury to lingual nerve. Also undercut and slanted lingual plate shapes were recognised as risk factors for contact/perforation between root apex and lingual plate. Therefore, proper screening and planning of high risk patients before third molar extraction is crucial.

A completely digital workflow aided by cone beam computed tomography scanning to maintain jaw relationships for implant-supported fixed complete dentures: A clinical study

Statement of problemThe conventional workflow for the fabrication of implant-supported fixed complete dentures (IFCDs) is complex and makes it impossible to maintain jaw relationships. A fully digital workflow might solve this problem. PurposeThe purpose of this clinical study was to develop a completely digital workflow aided by a cone beam computed tomography (CBCT) scan for the fabrication of IFCDs and to evaluate the accuracy of this workflow with regard to the maintenance of jaw relationships. Material and methodsAll participants received a preoperative CBCT scan while wearing radiographic diagnosis dentures and occluding in the maximum intercuspal position. After the implant surgery, CBCT scanning, intraoral scanning, and stereophotogrammetry were performed to identify jaw anatomy, soft tissue, and the 3-dimensional (3D) locations of the implants, respectively. Then, all data were merged to transfer jaw relationships and generate digital casts to fabricate interim prostheses. A posttreatment CBCT scan was performed while the participants were wearing the interim prostheses and occluding in the maximum intercuspal position. The preoperative and postoperative jaw relationships were compared by CBCT cephalometric analysis. A meaningful and unacceptable difference was defined as 0.8 degrees and 2.4 degrees, respectively. ResultsSix participants (6 jaw relationships, 9 arches, and 58 implants) were included. All interim prostheses were stable and achieved symmetric occlusion after only minimal adjustment. A total of 18 angles were measured. Three angles revealed a meaningful minimal difference, and 1 angle revealed an unacceptable minimal difference. No prosthodontic complications were reported during the study. ConclusionsA completely digital workflow for fabricating IFCDs achieved sufficient accuracy for the maintenance of jaw relationships throughout the treatment.