Preoperative Cone Beam Computed Tomography Research Articles

Agreement between cone-beam computed tomography and functional endoscopic sinus surgery for detection of pathologies and anatomical variations of the paranasal sinuses in chronic rhinosinusitis patients: A prospective study.

PurposeThe diagnosis of chronic rhinosinusitis requires a comprehensive knowledge of the signs and symptoms of the disease and an accurate radiographic assessment. Computed tomography (CT) is the superior imaging modality for diagnosis of chronic rhinosinusitis. However, considering the lower dose and higher resolution of cone-beam computed tomography (CBCT) compared to CT, this study aimed to assess the agreement between the findings of CBCT and functional endoscopic sinus surgery (FESS).Materials and MethodsThis descriptive prospective study evaluated 49 patients with treatment-resistant chronic rhinosinusitis who were candidates for FESS. Preoperative CBCT scans were obtained before patients underwent FESS. The agreement between the CBCT findings and those of FESS was determined using the kappa correlation coefficient. The frequency of anatomical variations of the paranasal sinuses was also evaluated on CBCT scans.ResultsSignificant agreement existed between pathological findings on CBCT scans and those of FESS, such that the kappa correlation coefficient was 1 for mucosal thickening, 0.644 for nasal deviation, 0.750 for concha bullosa, 0.918 for nasal polyp, 0.935 for ostiomeatal complex (OMC) obstruction, and 0.552 for infundibulum thickening. Furthermore, 95.9% of patients had 1 or more and 79.6% had 2 or more anatomical variations, of which nasal deviation was the most common (67.3%).ConclusionConsidering the significant agreement between the findings of CBCT and FESS for the detection of pathological changes in the paranasal sinuses, CBCT can be used prior to FESS to detect chronic rhinosinusitis and to assess anatomical variations of the OMC.

Effect of postoperative steroids on clinical outcomes and radiographic findings of horizontal alveolar ridge augmentation: A retrospective study.

The purpose of the study was to investigate if the prescription of oral postoperative steroids has an effect on clinical outcomes of horizontal ridge augmentation including implant placement and characteristics of the grafted bone. A retrospective chart review of 73 horizontal ridge augmentation cases was completed to assess the clinical outcomes, 53 of those cases were further assessed radiographically. Information was gathered regarding surgical technique, grafting materials, postoperative healing, medications used postoperatively, bone growth, and density changes as quantified on a cone-beam computed tomography (CBCT) scan. Statistical analysis was completed to identify whether the use of postoperative oral steroids altered outcomes. Steroids were used postoperatively following various horizontal ridge augmentation procedures. The use of tenting screws and resorbable membranes with a combination of osseous allograft and xenograft was used in 73 cases, 53 of which had preoperative and postoperative CBCT scans. Graft exposure occurred in five of the cases (9%), with the majority (n=4) among those with postoperative steroids, but this was not statistically significant (P-value=0.6510). Use of steroids was also not significantly associated with the number of courses of antibiotics (P-value>0.05), but it was significantly associated with increased number of postoperative visits (P-value<0.05). Among the subset for radiographic analysis (n=53), there were significant clinical and radiographic dimensional changes in alveolar ridge width with an average horizontal bone gain of 3.6mm. There were no statistically significant differences found in radiographic linear bone gain or clinical outcomes with the addition of steroids. A marginally statistically significant in the density of grafted bone was found with the addition of steroids (P-value>0.05). The prescription of postoperative steroids did not make a significant difference in clinical outcomes, success of implant placement or on radiographic assessment of grafted sites following horizontal alveolar ridge augmentation.

THE USE OF BUCCAL ANTROSTOMY BONE AS A GRAFT FOR CLOSURE OF ORO- ANTRAL FISTULA

INTRODUCTION: Oroantral fistula is an epithelialized, pathological and unnatural communication between the oral cavity and the maxillary sinus. OBJECTIVES: The aim of this study was to evaluate the use of buccal antrostomy bone as a graft for closure of oroantral fistula clinically and radiographically. MATERIALS AND METHODS: A prospective study was done on 10 patients complaining of oroantral fistulae following extraction of maxillary posterior teeth. The bony defect of the oroantral fistula was closed by anterior wall of maxillary sinus as a graft material and fixed to the surrounding bone using N-Butyl-2-Cyanoacrylate (Histoacryl®), then covered by buccal advancement flap. The patients were followed up clinically after 4, 6, 8 and 12 weeks postoperatively Radiographic evaluation was performed by cone beam computed tomography (CBCT) preoperatively and after 12 weeks postoperatively. RESULTS: Evaluation of the patients revealed that proper healing of the wound occurred in most of the patients except in 3 patients whose bone graft was exposed and removed. Radiographicaly, significant amount of bone was formed comparing the preoperative and postoperative CBCT of the patients. CONCLUSIONS: According to the results of the present study, it is concluded that the use of the buccal antrostomy wall as a bone graft fixed with N butyl cyanoacrylate proved successful results in closure of large oroantral fistula.

Vestibular bone thickness of the mandible in relation to the mandibular canal\u2014a retrospective CBCT-based study

BackgroundThe aim of this study was to assess vestibular bone thickness of the mandible in relation to the mandibular canal and position of the mental foramen in relation to the neighbouring teeth. Measurements were performed on radiographic cone-beam computed tomography (CBCT) images.MethodsThis retrospective study analysed 314 CBCTs, having been taken at the Clinic of Cranio-Maxillofacial and Oral Surgery, University of Zurich, Switzerland.ResultsCBCTs from 168 female and 146 male patients (median age 40.2 years) were analysed. Median bone thickness lateral to the nerve canal to the buccal mandibular cortical plate was ~ 4 mm immediately posterior to the mental foramen, increased to ≤ 6 mm over the next 30 mm, then decreased to ~ 3 mm at the level of the mandibular foramen. In two thirds of cases, both mental foramina were located near the second premolar (66.2% right, 67.7% left). Bone thickness and the position of the mental foramen showed marked intra- and interindividual variance.ConclusionsA preoperative CBCT is recommended for detailed planning of surgical interventions that may reach the mandibular canal (e.g. wisdom teeth removal, root resection, implant placement, bone block harvesting).

Targeted Endodontic Microsurgery: Computed Tomography–based Guided Stent Approach with Platelet-rich Fibrin Graft: A Report of 2 Cases

Endodontic microsurgery is a predictable alternative to nonsurgical treatment of persistent and recurrent apical periodontitis. The modern endodontic microsurgical procedure has been evolving in pace with technological advances. The introduction of modern innovations such as cone-beam computed tomographic (CBCT) imaging, 3-dimensional (3D) printing technology, and a 3D surgical guide designed with computer-aided software has allowed for a novel approach to the surgical site. The aim of these case reports was to describe root-end surgery with the use of the implant DDS-Pro planning software (Natrodent Polska, Poland), a 3D-printed surgical guide precisely positioned according to the preoperative CBCT scan measurements (CS 8100; Carestream Dental, Atlanta, GA), and a modified soft tissue access. A hollow trephine bur was used to perform the osteotomy, resection of the root, and enucleation of the lesion. The intact cortical plate was salvaged and used as a graft along with plasma-rich fibrin acquired preoperatively from the patient’s blood. The positioning guide allowed the clinicians to precisely achieve targeted tissues and shorten the procedure time. Modified soft tissue management helped achieve a small surgical wound for uneventful healing. A less than 12-month CBCT follow-up of both cases showed complete 3D healing of the surgical site.

Preliminary application assessment of individualized three-dimensional printing titanium mesh combined with guided bone regeneration for repairing alveolar bone defects

Objective: To preliminarily evaluate the clinical effect of the three-dimensional (3D) printing individualized titanium mesh combined with guided bone regeneration technology for repairing alveolar bone defects. Methods: Six patients with alveolar bone defects (4 males and 2 females, aged 18-27 years, mean 23.3 years) were selected from the Department of Oral Implantology, Stomatological Hospital of Chongqing Medical University from January to June 2018. The patients' cone-beam CT (CBCT) data was imported into the digital design software, and the individualized titanium meshes were designed based on the ideal bone mass around the implant, alveolar bone morphology and soft tissue condition. Then, the ".stl" files were output and the meshes were fabricated by 3D printing technology. The individualized titanium meshes combined with the mixture of autogenous bone and bone substitute materials were used to augmentation during operation. All patients were reviewed at 1, 3 and 6 months after surgery to observe the complications and evaluate the effect of bone augmentation. After taking out the titanium mesh, the CBCT was compared with the preoperative CBCT. The increased bone height and bone width were measured and the bone incremental volume was calculated. Results: Titanium mesh exposure occurred in 2 patients with no obvious infection, and no early removal. In 6 patients, the bone width increased by 1.75-7.54 mm (mean 3.58 mm), the bone height increased by 0.91-11.80 mm (mean 3.37 mm), and bone incremental volume increased by 247-676 mm(3) (mean 503 mm(3)). All of the cases showed sufficiently grafted volume for implant placement. Conclusions: The individualized 3D printing titanium meshes combined with guided bone regeneration could repair alveolar bone defects with excellent clinical effect, but a better design needed to be explored in the future to solve or delay the exposure of titanium mesh.

Evaluating the risk of post-extraction inferior alveolar nerve injury through the relative position of the lower third molar root and inferior alveolar canal

The aim of this study was to introduce a method to evaluate the risk of inferior alveolar nerve (IAN) injury following the extraction of impacted lower third molars. Two hundred impacted lower third molars adjacent to the IAN were evaluated. These were divided into four classification groups according to preoperative cone beam computed tomography (CBCT) findings: AR, apical region; LT, lateral region of the tapered root; LE, lateral region of the enlarged root; AE, adjacent to the enlarged root. All teeth were dislocated along the long axis or arc of the root by tooth sectioning technique and extracted by a single surgeon. The primary outcome variable was postoperative neurosensory impairment of the IAN. The χ2 test was used to evaluate differences in postoperative IAN injury between the classifications. Logistic regression analysis was used to evaluate the risk factors for postoperative IAN injury. The overall incidence of postoperative IAN injury was 7%. Specifically, most injuries involved classification AE (AE 36%, LE 8.6%, LT 3.6%, AR 0%), and the difference was statistically significant (P< 0.05). Logistic regression showed that classification AE was the only risk factor for postoperative IAN injury (P< 0.001). According to preoperative CBCT, the risk of postoperative IAN injury is higher when the IAN is adjacent to the enlarged part of the root.

Use of Cone-Beam Computed Tomography in Performing Submandibular Sialolithotomy

Sialolithotomy for submandibular gland lithiasis is a common procedure often performed in the office setting, with the patient under local anesthesia. The location, size, and number of the sialoliths can greatly influence the indication owing to the difficulty of the procedure for hilar and proximal calculi. The purpose of the present study was to report our experience regarding the advantages of using preoperative cone-beam computed tomography (CBCT) to evaluate submandibular gland lithiasis in patients undergoing sialolithotomy for calculi located anywhere in the area of Wharton's duct, with special regard to hilar and proximal calculi. We performed a retrospective study by reviewing the medical records of patients with a diagnosis of sialolithiasis of the submandibular gland using CBCT performed the day of stone removal by sialolithotomy. We have described the operative technique and the CBCT landmarks used for intraoperative orientation and control. Thirty-two patients with submandibular sialolithiasis were included in the present study. A total of 51 salivary stones were identified using CBCT. Proximal and hilar calculi were encountered in 14 cases. The number of calculi diagnosed using CBCT matched the number of surgically removed calculi in all cases. Transient lingual nerve hypoesthesia was encountered in 2 patients. No obstructive symptoms recurred after surgery. We found that preoperative CBCT allows for an optimal understanding of the individual stone configuration in relation to the patient's anatomy. It allows for easy identification of the calculi during sialolithotomy, leading to greater confidence in approaching proximal and hilar stones.

Effects of different loading protocols on the bone remodeling volume of immediate maxillary single implants: A 2- to 3-year follow-up.

The purpose of this study was to assess the effect of different loading protocols (immediate or delayed) on bone volume remodeling of an immediate implant-supported single crown in the maxilla with a follow-up from 2 to 3 years. Patients presenting a failing tooth have been rehabilitated with implant-supported single crowns. Data of patients with a survey from 2 to 3 years after baseline surgery were retrospectively acquired. One implant per patient was randomly selected during data analysis and assigned to one of two predictor groups: the loading protocol, 9 immediate vs 13 delayed loading; and tooth position, 9 incisors vs 9 canines. Cumulative survival rates were recorded; loss of crestal bone volume was assessed with cone beam computed tomography (CBCT) by means of software that superimposed the preoperative and postoperative CBCT scan data (Matrix Laboratory) and by destascan software. Twenty-two patients were enrolled. No postoperative complications or implant failures were recorded. Bone volume loss from the 2- to 3-year follow-up period ranged between 19.1% and 22.0%, without significant differences between the two loading protocols. Irrespective of the tooth site, intragroup analyses revealed the presence of significant differences between preoperative and postoperative time evaluations for all the analyzed groups and subgroups. Volumes at baseline (ranging between 0.546 cc and 0.553 cc) recorded significant loss of approximately 110 mm3 (P values ≤ .0001) for both loading protocols. The volume at the postoperative evaluation ranged between 0.428 cc and 0.442 cc. Considering tooth site in the analysis, the subgroups showed similar behaviors at the crestal bone level. However, bone loss at the apex of the implant appeared to be lower for incisors than canines. This study attested that the loss of crestal bone around an immediate implant-supported single crown depended on neither the loading protocol nor the tooth site.

A Novel Prefabricated Grid for Guided Endodontic Microsurgery

IntroductionThis study aimed to introduce a novel method using cone-beam computed tomographic (CBCT) imaging and prefabricated grids to guide apical access during endodontic microsurgery and to compare its accuracy with that of the nonguided method. MethodsForty-two roots from human cadaver jaws were selected. Twenty-one were randomly assigned to the experimental group (grid based) and their contralateral counterparts to the control group (nonguided). Preoperative CBCT images were used to design a drill path that intended to reach the palatal/lingual aspect of the roots without attempting to complete the osteotomy or to resect the entire root end. In the experimental group, prefabricated metal grids used during imaging and surgery acted as a reference in the design and drilling. Postoperative CBCT volumes were superimposed on the preoperative volumes, and the distances between the actual drill paths and the target points were measured. A dichotomized outcome of success versus failure was also recorded and compared. Statistical analysis was performed using the paired t test and Fisher exact test. ResultsThe mean deviation of the drill paths from the target points was 0.66 mm ± 0.54 mm (mean ± standard deviation) for grid-based drilling and 1.92 mm ± 1.05 mm (mean ± standard deviation) for nonguided drilling (P < .001). Grid-based drilling was on average 1.27 mm (95% confidence interval, 0.81–1.72 mm) closer to the target point than nonguided drilling. The probability of successful drilling was also significantly higher with grids than without grids (P = .02). ConclusionsThe proposed method of guided osteotomy and root-end resection using prefabricated grids was more accurate than the nonguided method.

A 2-year prospective case series on volumetric changes, PROMs, and clinical outcomes following sinus floor elevation using deproteinized bovine bone mineral as filling material.

A sinus floor augmentation may be indicated when a lack of hard tissue impedes implant placement. Although clinically successful, evidence supporting the long-term three-dimensional stability of the grafted volume is scarce. Second, evidence on the patient's acceptance of this type of treatment is limited. First is to evaluate the changes in graft volume after lateral wall sinus lifting based on superimposed cone beam computed tomography (CBCT) images and then to assess patient-reported outcome measures (PROMs) and clinical outcomes. Partially edentulous patients in need of a sinus lift and fixed reconstruction on at least two neighboring implants were selected for a prospective case series. Lateral wall sinus augmentation was performed using deproteinized bovine bone mineral (DBBM) as the only filling material. Volumetric changes were quantified on the basis of a preoperative CBCT and three postoperative CBCTs (at 2 weeks, 3 months, and 2 years). PROMs and clinical parameters were registered. Twenty-two patients (7 males, 15 females; mean age 59 years) participated of which three patients dropped out during the follow up. Graft volumes amounted to 1418.26 mm3 at 2 weeks, 1201.21 mm3 at 3 months, and 1130.13 mm3 at 2 years postoperative pointing to a relative graft volume stability of 79.7%. Swelling was the leading symptom during the first week. A peak in visual analogue scale scores was observed for pain, swelling, and hematoma the day of surgery and 1 day postoperation with a statistically significant decline between days 3 and 7. Hemorrhage and nose bleeding occurred in 18.2% and 27.3% of the subjects, respectively. About 95.5% of the subjects would undergo the treatment again. All implants integrated successfully and demonstrated healthy clinical conditions. Lateral wall sinus augmentation using DBBM as the only filling material is a viable treatment concept given limited graft resorption, good patients' tolerance, and clinical outcomes.

When and how do endodontic specialists use cone-beam computed tomography?

This study investigated the use of cone-beam computed tomography (CBCT) by endodontists in Germany and Switzerland. Sixty-eight German endodontic specialists (G-ES), 22 Swiss endodontic specialists (CH-ES) and 95 dentists with a German Master of Science in endodontics (MSc) were invited to participate. Data on the timing of diagnostic assessments, endodontic case difficulty and indications for CBCT use were collected by questionnaire. The frequencies of pre-, intra- and postoperative use of periapical radiography and CBCT were analysed by case difficulty level. In high difficulty cases, access to a CBCT device was significantly associated with the frequency of both pre- and intraoperative CBCT use. The type of endodontic qualification had a significant impact on the rate of preoperative CBCT use in high difficulty cases. German endodontic specialists used preoperative CBCT more frequently than CH-ES and MSc. Our findings show that CBCT is a valuable imaging tool for endodontists, particularly in high difficulty cases.

Three-rooted maxillary first premolars incidentally detected on cone beam CT: an in vivo study.

To explore the incidence and analyze the morphology of three-rooted maxillary first premolars (MFPs) incidentally detected on cone beam computed tomography (CBCT) scans. Of 1328 patients who underwent CBCT scans of the maxilla, only patients with three-rooted MFPs were selected. Morphological features, including the lengths and diameters of palatal, mesiobuccal (MB) and distobuccal (DB) roots, the positions of bucco-palatal (B-P) bifurcations, the distances between root canal bifurcations and cementoenamel junctions (CEJs) and the distances between the apical thirds of the roots, were measured. The canal configuration and the visibility of root canals were also evaluated. A total of 16/1328 (1.2%) patients had one or two three-rooted MFPs, and a total of 22/2656 (0.8%) three-rooted MFPs were enrolled. The lengths and diameters of palatal roots were significantly greater than those of other roots. The positions of B-P bifurcations were located mainly at the middle third of the root. The median distances between root canal bifurcations and CEJs were 3mm for B-P bifurcations and 5.2mm for MB-DB bifurcations. The distance between MB and DB roots was significantly shorter than the distances between other root pairs. All teeth had a type VIII canal configuration. Palatal roots exhibited the best visibility of root canals, whereas the worst visibility was observed within DB roots. A gender-related relationship was observed only for the lengths of the roots. The occurrence of three-rooted MFPs is not unusual; therefore, preoperative CBCT evaluation could be suggested whenever endodontic procedures are planned on an MFP.

Association between Marginal Bone Loss and Bone Quality at Dental Implant Sites Based on Evidence from Cone Beam Computed Tomography and Periapical Radiographs.

Objective:The aim of this study was to assess bone quality in patient's preoperative cone beam computed tomography (CBCT) and their relation with marginal bone loss at implant placement sites over follow-up periods.Materials and Methods:In this retrospective cross-sectional study, 100 implants were evaluated. The implants had been placed in the maxillary and mandibular edentulous areas. Bone quality at implant placement sites was measured on preoperative CBCTs and then classified by two observers according to Lekholm and Zarb classification. Marginal bone height was then measured on periapical radiographs obtained at baseline and then 6, 12, 18, 24, and 30 months’ follow-up periods from a reference point (implant shoulder) to the bone-implant interface. The relation between bone quality and bone loss was assessed. ANOVA was used to compare mean difference among groups and Pearson correlation coefficient to assess the correlation between observers. All statistical analyses were performed at 0.05 significance level using Stata 11 software (StataCorp, College Station, TX, USA).Results:Of 100 implants, 48 were placed in the maxilla and 52 in the mandible. There was no significant difference between bone quality and the mean bone loss at follow-up periods. Using Pearson's correlation coefficient, it was shown that with an increase in bone quality, marginal bone loss was decreased at follow-up periods.Conclusions:The results confirmed that during the follow-up periods, less bone loss was observed in implant areas with higher bone quality and CBCT is a reliable tool for assessing bone quality at implant placement sites and estimation of subsequent treatment prognosis.

Unusual anatomy of permanent maxillary and mandibular molars: Case reports

Introduction. The anatomy and morphology of the roots and root canal systems of multi-rooted teeth, especially the molars, shows numerous variations. Preoperative radiography, in particular cone-beam computed tomography (CBCT), has exceptional significance in detecting anatomical variations and unusual root canal morphologies, which are extremely important to be familiar with in order to undertake successful endodontic therapy and minimize procedural errors. Outline of cases. This report presents cases of incidental diagnosis of an unusual root anatomy and root canal morphology of permanent molars in two patients. Diagnosis in the first case was made using orthopantomography and confirmed after extraction therapy. The second case reviled unusual root anatomy and root canal morphology of the permanent molar after preoperative CBCT imaging. Conclusion. Anatomical and morphological variations of roots and root canal systems can occur in any tooth. Clinicians should expect these variations, which should be thoroughly investigated when considering dental treatment.

Determining the Margin of Safety for Damaging the Sphenoid Sinus with Nasal Septum Osteotome during Le Fort I Surgery in Young Adults.

Nasal septum (Obwegeser) osteotome is a basic instrument used for separating the nasal septum and maxilla during Le Fort I osteotomy. If this instrument is placed too high or tilted into the nasal cavity, sphenoid sinus and various adjacent vital structures may be damaged and serious bleeding, neurological complications, or blindness or even death may occur. The aim of this study is to determine the margin of safety for damaging the sphenoid sinus and the adjacent structures with nasal septum osteotome in the young adults: 49 male and 51 female patients between 15 and 25 ages who required a Cone Beam Computed Tomography (CBCT) examination as part of their routine examination. In the study sample consisting of CBCT images, the aimed surgical line, the line between spina nasalis anterior and vomer and the base of sphenoid sinus (undesired line), and tilt angle between surgical and undesirable lines were measured. As the primary outcome of this study, margin of safety for damaging the sphenoid sinus and adjacent vital structures with nasal septum osteotome during Le Fort surgeries in young adults recommended as 5 mm and 120. For this reason the importance of planning with preoperative CBCT before Le Fort I osteotomies has been revealed.

Three-dimensional region-based study on the relationship between soft and hard tissue changes after orthognathic surgery in patients with prognathism.

Both deep understanding and reliable prediction of postoperative soft tissue changes are crucial for planning orthognathic surgery. Instead of estimating soft tissue responses by measuring individual landmark changes, this study aimed to investigate the relationship (ratio) between soft and hard tissue movements in different facial regions through three-dimensional cone-beam computed tomography (CBCT). Preoperative and postoperative CBCT images were superimposed using the surface registration method on the basis of the cranial base, and 10 facial regions of interest were defined. Region-based volumetric subtractions between the preoperative and postoperative segments were performed. The volumetric differences and surface of each region were used to estimate the average movement. Correlation and regression analyses were performed to examine the relationships between the corresponding soft and hard tissue movements. An overall pattern of facial soft tissue movement was observed in patients with prognathism who underwent orthognathic surgery. The experiment results have shown that mean ratios for the average soft-to-hard tissue movements in the facial regions varied, which may not exactly be similar to the published reports because of the population biocharacteristics and study methods, but the trend is in agreement with the previous studies. Additionally, the prediction capability of the regression model was significantly high, ranging from 0.786 to 0.857, in upper lip, upper vermilion, and chin regions, thus demonstrating that the skin outline changes in these critical regions could be reliably predicted from the underlying bone movements. These results could likely be applied in future soft tissue simulation in orthognathic surgery.

Validation of a windowing protocol for accurate in vivo tooth segmentation using i-CAT cone beam computed tomography.

Validation of three-dimensional (3D) reconstructions of full dental arches with crowns and roots based on cone beam computed tomography (CBCT) imaging represents a key issue in 3D digital dentistry. The aim of the study was to search for the most accurate in vivo windowing-based manual tooth segmentation using CBCT. The null hypothesis was that all applied windowing protocols were equivalent in terms of in vivo tooth volume measurement using CBCT. This retrospective study was based on preoperative CBCT images from patients who underwent further tooth extractions for reasons independent of this study. Written informed consent was obtained from all the participants, and the study was approved by the Ethics Committee of Cliniques Universitaires Saint Luc (Brussels, Belgium). The radiological protocol was I-CAT CBCT, 0.3 mm slice thickness, 8 cm × 16 cm field of view, 120 kVp, and 18 mAs. A total of 36 teeth were extracted from 14 patients between the ages of 18 and 68 years. Using 3D Slicer software, segmentations were performed twice by 2 independent observers, with a 1-month time period between the 2 segmentations to study intraand inter-observer repeatability and reproducibility. Four windowing protocols (level/window) were applied: 1. 1131/1858, 2. 2224/4095, 3. 1131/4095, and 4. AUTO, an automatic protocol provided by default by the software. A total of 576 segmentations were performed. Tooth volumes were automatically calculated using the software. To compare the volumes obtained from CBCT segmentations with a gold-standard method, we laser-scanned the extracted teeth. Excellent intraand inter-observer intraclass correlations were found for all of the protocols used. The best windowing protocol was 1131/1858 for both observers. Tooth volumes were obtained by manual segmentation of the CBCT images and using windowing protocol 1131/1858. No significantly different tooth volumes were found by laser scanning. Our null hypothesis was rejected. Only windowing protocol 1131/1858 allowed for significantly closer 3D in vivo segmentation of a tooth compared to I-CAT CBCT, with excellent intra-observer repeatability and inter-observer reproducibility.

Cone Beam Computed Tomography Assessment of the Buccal Bone Thickness in Anterior Maxillary Teeth: Relevance to Immediate Implant Placement.

Peri-implant bone thickness is an important local factor that could influence esthetic outcomes in immediate implant therapy. The aim of this study was to assess the thickness of the buccal bone overlying the anterior maxillary teeth in Kenyans. A total of 184 cone beam computed tomography (CBCT) scans that met the inclusion criteria were retrospectively studied. Buccal bone thickness of all maxillary anterior teeth was assessed, resulting in a total of 1,104 teeth. Measurements were taken on sagittal views at a point 4 mm below the cementoenamel junction (M1) and at the mid-root level (M2). The data were analyzed using SPSS software (version 20, IBM), and statistical significance was set at P ≤ .05. Mean buccal bone thickness of the teeth studied was 0.55 ± 0.38 mm at M1 and 0.60 ± 0.30 mm at M2. Missing buccal bone wall was observed in 31.61% (349 teeth) of all teeth at M1 and in 21.38% (236 teeth) of all teeth at M2. The majority of the teeth had a thin buccal bone wall (< 1 mm) at M1 (56.34%) and at M2 (68.48%), whereas a thick buccal bone (≥ 1 mm) was only observed in 12.05% of teeth at M1 and in 10.14% of teeth at M2. Thin buccal bone was mainly found in central incisors, while thick buccal bone wall was found mainly in canines. The thickness of buccal bone at M1 decreased with an increase in age. Contour augmentation would be necessary in most of these cases, as the buccal bone was typically thin. The thickness at the cervical portion was inversely correlated with age. One in every four of the cases would not be ideal for flapless immediate implant placement due to a missing buccal bone wall. Preoperative CBCT analysis of the buccal wall is recommended for appropriate treatment planning.

A novel method for periapical microsurgery with the aid of 3D technology: a case report

BackgroundThree-dimensional (3D) technology has gained wide acceptance in dentistry. It has been used for treatment planning and surgical guidance. This case report presented a novel treatment approach to remove cortical bone and root-end during periapical surgery with the help of Cone-Beam Computed Tomography (CBCT), Computer Aided Design (CAD) and three-dimensional (3D) printing technology.Case presentationA 37-year-old female patient presented with a large periapical lesion of left maxillary lateral incisor and canine was referred for microsurgical endodontic surgery. The data acquired from a preoperative diagnostic CBCT scan and an intra-oral scan was uploaded into surgical planning software and matched. A template that could be used to locate root-ends and lesion areas was virtually designed based on the data and was fabricated using a 3D printer. With the guidance of the template, the overlying cortical bone and root-end were precisely removed by utilizing a trephine with an external diameter of 4.0 mm. The patient was clinically asymptomatic at a six-month follow-up review. One year after the surgery, the lesion was healing well and no periapical radiolucency was observed on radiographic examination.ConclusionsThe digitally designed directional template worked in all aspects to facilitate the periapical surgery as anticipated. The root-ends were accurately located and resected. The surgical procedure was simplified, and the treatment efficiency was improved. This technique minimized the damage and reduced iatrogenic injury.