[Non-surgical peri-implantitis treatment with or without systemic antibiotics]. / Initiële behandeling van peri-implantitis met of zonder systemische antibiotica.

This study investigated the effect of initial nonsurgical treatment in patients with peri-implantitis with or without prescription of an antibiotic regimen consisting of amoxicillin and metronidazole. For this purpose, patients with peri-implantitis were randomized into a group of initial treatment with antibiotics and a group without antibiotics. They were re-evaluated 12 weeks after treatment. Analyses were performed at the patient level at 1 peri-implant pocket per patient. Both groups showed significant peri-implant pocket depth reductions after initial treatment. Treatment with antibiotics resulted in a higher mean reduction in peri-implant pocket depth than when no antibiotics were used, but this difference did not reach statistical significance. Only 2 implants, 1 in each group, showed a successful outcome of a peri-implant pocket depth ofunder ≤ 5 mm and with an absence of bleeding and pus after probing. Initial treatment with or without antibiotics is ultimately not sufficient to fully treat peri-implantitis; additional surgical procedures will often be required.

Marginal and internal fit of 3D printed resin graft substitutes mimicking alveolar ridge augmentation: An in vitro pilot study.

Recent improvements in additive manufacturing technologies may facilitate the use of customized 3D printed grafts for horizontal and vertical augmentation of the atrophic alveolar ridge. The accurate fit of such grafts could reduce the clinical treatment time and contribute optimal bone regeneration. The aim of this in vitro study was to evaluate the marginal and internal fit of 3D printed resin grafts as they could be used for alveolar ridge augmentation. Alveolar ridge morphologic data were derived from the Cone Beam Computed Tomography (CBCT) scans of six patients with alveolar bone defects. These data were transferred to a segmentation program to produce virtual 3D reconstructions of the alveolar ridge models. Using a Computer Aided Design (CAD) program, the alveolar bone defects were defined and customized grafts were designed and both the defects as well as the grafts generated (CAM) as 3D projects. These projects were imported into a 3D printer and were manufactured in resin. Hereafter, the grafts were fitted to the defect sites of the corresponding models and new CBCT scans were performed. Based on these scans, measurements were made at the marginal and internal part of the fitted grafts to evaluate the marginal and internal fit, respectively. The statistical analysis revealed that the mean marginal fit was significantly better (P < 0.05) than the mean internal fit. The fit of the grafts was dependent on the shape and on the size of the grafts. Specifically, the total void surface between the fitted graft and the corresponding defect site was significantly larger in the large-defect grafts than the small-defect grafts (P < 0.05). Within the limitations of the study, it could be demonstrated that it is possible to fabricate 3D printed resin grafts with acceptable fit in customized shapes, when combining CBCT scans and computer aided design and 3D printing techniques.

Augmented and virtual reality in dental medicine: A systematic review.

BACKGROUND: The aim of this systematic review was to provide an update on the contemporary knowledge and scientific development of augmented reality (AR) and virtual reality (VR) in dental medicine, and to identify future research needs to accomplish its clinical translation. METHOD: A modified PICO-strategy was performed using an electronic (MEDLINE, EMBASE, CENTRAL) plus manual search up to 12/2018 exploring AR/VR in dentistry in the last 5 years. Inclusion criteria were limited to human studies focusing on the clinical application of AR/VR and associated field of interest in dental medicine. RESULTS: The systematic search identified 315 titles, whereas 87 abstracts and successively 32 full-texts were selected for review, resulting in 16 studies for final inclusion. AR/VR-technologies were predominantly used for educational motor skill training (n = 9 studies), clinical testing of maxillofacial surgical protocols (n = 5), investigation of human anatomy (n = 1), and the treatment of patients with dental phobia (n = 1). Due to the heterogeneity of the included studies, meta-analyses could not be performed. CONCLUSIONS: The overall number of includable studies was low; and scientifically proven recommendations for clinical protocols could not be given at this time. However, AR/VR-applications are of increasing interest and importance in dental under- and postgraduate education offering interactive learning concepts with 24/7-access and objective evaluation. In maxillofacial surgery, AR/VR-technology is a promising tool for complex procedures and can help to deliver predictable and safe therapy outcomes. Future research should focus on establishing technological standards with high data quality and developing approved applications for dental AR/VR-devices for clinical routine.

[Replacing heavily damaged molars with the use of 3D-techniques]. / Vervanging van ernstig beschadigde molaren met behulp van 3D-technieken.

Seriously damaged molars can be replaced by autotransplantation with the help of 3D techniques. In the present case, involving an 18-year old patient, 18, 38 and 48 were used to replace, respectively, 14, 36 and 37. Preoperatively, the width of the crowns and the root development of 18, 38 and 48 were analysed using 3D imaging. During the autotransplantation procedure, the new alveoli are formed with the help of replicas of the donor molars printed in 3D, in order to prevent iatrogenic damage to the actual donor molars.. The extra-alveolar time was less than 2 minutes for all donor molars. Postoperative follow-up showed physiologic integration of the transplanted molars. There was no ankylosis. Autotransplantation with the help of 3D techniques makes it possible to perform complex procedures with good results.

Autotransplantation of teeth using computer-aided rapid prototyping of a three-dimensional replica of the donor tooth: a systematic literature review.

This systematic review provides an overview of studies on autotransplantation techniques using rapid prototyping for preoperative fabrication of donor tooth replicas for preparation of the neo-alveolus. Different three-dimensional autotransplantation techniques and their treatment outcomes are discussed. The systematic literature search yielded 19 articles that satisfied the criteria for inclusion. These papers described one case-control study, four clinical observational studies, one study with a clinical and in vitro part, four in vitro studies, and nine case reports. The in vitro studies reported high accuracy for the printing and planning processes. The case reports all reported successful transplantation without any pathological signs. The clinical studies reported a short extraoral time of the donor tooth, with subsequent success and survival rates of 80.0-91.1% and 95.5-100%, respectively. The case-control study reported a significant decrease in extraoral time and high success rates with the use of donor tooth replicas. In conclusion, the use of a preoperatively designed surgical guide for autotransplantation enables accurate positional planning, increases the ease of surgery, and decreases the extraoral time. However, the quality of the existing body of evidence is low. Further research is therefore required to investigate the clinical advantages of this innovative autotransplantation technique.

Bone regeneration in critical-sized bone defect enhanced by introducing osteoinductivity to biphasic calcium phosphate granules.

OBJECTIVES: Biphasic calcium phosphate (BCP) is frequently used as bone substitute and often needs to be combined with autologous bone to gain an osteoinductive property for guided bone regeneration in implant dentistry. Given the limitations of using autologous bone, bone morphogenetic protein-2 (BMP2)-coprecipitated, layer-by-layer assembled biomimetic calcium phosphate particles (BMP2-cop.BioCaP) have been developed as a potential osteoinducer. In this study, we hypothesized that BMP2-cop.BioCaP could introduce osteoinductivity to BCP and so could function as effectively as autologous bone for the repair of a critical-sized bone defect. MATERIALS AND METHODS: We prepared BMP2-cop.BioCaP and monitored the loading and release kinetics of BMP2 from it in vitro. Seven groups (n = 6 animals/group) were established: (i) Empty defect; (ii) BCP; (iii) BCP mixed with biomimetic calcium phosphate particles (BioCaP); (iv) BCP mixed with BMP2-cop.BioCaP; (v) BioCaP; (vi) BMP2-cop.BioCaP; (vii) BCP mixed with autologous bone. They were implanted into 8-mm-diameter rat cranial critical-sized bone defects for an in vivo evaluation. Autologous bone served as a positive control. The osteoinductive efficacy and degradability of materials were evaluated using micro-CT, histology and histomorphometry. RESULTS: The combined application of BCP and BMP2-cop.BioCaP resulted in significantly more new bone formation than BCP alone. The osteoinductive efficacy of BMP2-cop.BioCaP was comparable to the golden standard use of autologous bone. Compared with BCP alone, significantly more BCP degradation was found when mixed with BMP2-cop.BioCaP. CONCLUSION: The combination of BCP and BMP2-cop.BioCaP showed a promising potential for guided bone regeneration clinically in the future.

Histatin 1 Enhances Cell Adhesion to Titanium in an Implant Integration Model.

Cellular adhesion is essential for successful integration of dental implants. Rapid soft tissue integration is important to create a seal around the implant and prevent infections, which commonly cause implant failure and can result in bone loss. In addition, soft tissue management is important to obtain good dental aesthetics. We previously demonstrated that the salivary peptide histatin 1 (Hst1) causes a more than 2-fold increase in the ability of human adherent cells to attach and spread on a glass surface. Cells treated with Hst1 attached more rapidly and firmly to the substrate and to each other. In the current study, we examine the potential application of Hst1 for promotion of dental implant integration. Our results show that Hst1 enhances the attachment and spreading of soft tissue cell types (oral epithelial cells and fibroblasts) to titanium (Ti) and hydroxyapatite (HAP), biomaterials that have found wide applications as implant material in dentistry and orthopedics. For improved visualization of cell adhesion to Ti, we developed a novel technique that uses sputtering to deposit a thin, transparent layer of Ti onto glass slides. This approach allows detailed, high-resolution analysis of cell adherence to Ti in real time. Furthermore, our results suggest that Hst1 has no negative effects on cell survival. Given its natural occurrence in the oral cavity, Hst1 could be an attractive agent for clinical application. Importantly, even though Hst1 is specific for saliva of humans and higher primates, it stimulated the attachment and spreading of canine cells, paving the way for preclinical studies in canine models.

[Autotransplantation 2.0. Considerations, results and the latest techniques]. / Autotransplantatie 2.0. Overwegingen, uitkomsten en nieuwste technieken.

Autotransplantation is a valuable technique offering a physiological type of tooth replacement to patients with missing teeth. Teeth with open apices (50-75% apical closure) will regenerate with vitality following autotransplantation. The success rate following an autotransplantation is 82%. The remaining 18% can usually still be treated successfully with a simple additional treatment. The tooth survival rate 10 years after autotransplantation is higher than 90%. The use of 3D techniques makes it possible to create a pre-operative replica of the donor tooth. With this, a new alveolus can be prepared at the transplant site even before extraction. This technique reduces the extra-alveolar time for the donor tooth and minimises the possibility of iatrogenic damage. This results in a streamlined procedure, enabling better planning with better results.

The effect of implant placement in patients with either Kennedy class II and III on oral health-related quality of life: a prospective clinical trial.

There is little evidence of the effect of implants restored with fixed partial dentures on oral health-related quality of life (OHRQoL) in partially edentulous Kennedy class II and III patients. The aim of this study was to determine the change in OHRQoL in Kennedy classification II and III patients treated with a two-implant-supported fixed dental prosthesis (FDP). Kennedy class II and III patients received dental implants and an FDP. Oral health-related quality of life was measured by administration of the Oral Health Impact Profile-14 (OHIP-14NL) questionnaire at intake (T1), 2 weeks after surgery (T2) and after 1 year of loading (T3). The mean OHIP score at T1 was 6·5 ± 1·2, 2·4 ± 1·0 at T2, and 0·9 ± 0·3 at T3. There was a statistically significant difference between T1 and T2 (P = 0·002) and T1 and T3 (P < 0·001) but not between T2 and T3 (P = 0·407). The OHIP score in Kennedy II patients decreased from 4·8 ± 3·2 at T1 to 1·5 ± 2·0 at T2 and 1·1 ± 1·8 at T3, and that in Kennedy III patients decreased from 8·9 ± 9·6 at T1 to 3·6 ± 8·9 at T2 and 0·8 ± 2·2 at T3. There were no statistically significant differences in the reductions in Kennedy II and III patients. Oral health-related quality of life changed positively in patients treated with implants and an FDP in both groups. There was no change in OHRQoL between the times of implant placement and FDP placement.

Evaluation of the implant-related restorative undergraduate programme at ACTA, the Netherlands. Part I: students' satisfaction.

INTRODUCTION: Due to the increasing use of dental implants, many future dentists will encounter implant-related procedures in general practice. Over the past decade, implant dentistry is more and more often included in undergraduate curricula. Very little is known about students' satisfaction regarding implant-related undergraduate programmes, as minimal analyses are performed. In particular, a lack of information exists regarding programmes where undergraduates restore implants. This study describes an evaluation of the students' satisfaction regarding the implant-related restorative undergraduate programme at ACTA, the Netherlands. MATERIAL AND METHODS: After clinical examination and establishment of the treatment plan, undergraduates were required to assist postgraduate implantology students during surgery. All patients received Straumann (Basel, Switzerland) implants. The restorative phase of the treatment was subsequently performed by the undergraduates. A students' questionnaire was developed. All questions were exclusively on the restorative part of the implant-related programme. RESULTS: In total, 90 patients were treated by 78 undergraduates. 146 Straumann implants were restored with 121 restorations. The most common restoration was a single crown (80.2%), followed by three-unit fixed partial dentures (12.4%). The questionnaires showed a high rate of students' satisfaction concerning the restorative implant programme. Students replied they think they can manufacture an implant-supported crown or FDP without supervision after following the programme. In their opinion, the existence of the restorative programme should definitely be continued. CONCLUSION: According to positive student perceptions, an implant-related restorative programme should be recommended for implementation in undergraduate dental curricula. The programme at ACTA could be used as a template for other universities.

A review paper on biomimetic calcium phosphate coatings.

Biomimetic calcium phosphate coatings have been developed for bone regeneration and repair because of their biocompatibility, osteoconductivity, and easy preparation. They can be rendered osteoinductive by incorporating an osteogenic agent, such as bone morphogenetic protein 2 (BMP-2), into the crystalline lattice work in physiological situations. The biomimetic calcium phosphate coating enables a controlled, slow and local release of BMP-2 when it undergoes cell mediated coating degradation induced by multinuclear cells, such as osteoclasts and foreign body giant cells, which mimics a physiologically similar release mode, to achieve sustained ectopic or orthotopic bone formation. Therefore, biomimetic calcium phosphate coatings are considered to be a promising delivery vehicle for osteogenic agents. In this review, we present an overview of biomimetic calcium phosphate coatings including their preparation techniques, physico-chemical properties, potential as drug carrier, and their pre-clinical application both in ectopic and orthotopic animal models. We briefly review some features of hydroxyapatite coatings and their clinical applications to gain insight into the clinical applications of biomimetic calcium phosphate coatings in the near future.

Annual bone loss and success rates of dental implants based on radiographic measurements.

OBJECTIVES: Bone loss around dental implants is generally measured by monitoring changes in marginal bone level using radiographs. After the first year of implantation, an implant should have <0.2 mm annual loss of marginal bone level to satisfy the criteria of success. However, the process of measuring marginal bone level on radiographs has a precision of 0.2 mm (or more) owing to variations in exposure geometry, exposure time and observer perception. Therefore, the value of the annual loss may vary considerably, especially when short intervals are considered. This study investigates how the success rate of dental implants depends on the way annual bone loss is calculated. METHODS: Panoramic radiographs of 82 implant patients with an average follow-up of 10.4 years were analysed. Marginal bone levels near the implants were indicated by one observer. The annual loss of marginal bone level was determined according to four different calculation methods. RESULTS: The methods yielded success rates of 9%, 45%, 81% and 89%. CONCLUSIONS: The success rate of dental implants measured on radiographs greatly depends on the details of the calculation method. Without rigorous standardization, annual bone loss and implant success rate are not well defined.

Implant dentistry in postgraduate university education. Present conditions, potential, limitations and future trends.

INTRODUCTION: In recent years, opportunities for postgraduate university education in implant dentistry have increased significantly, with an increase in both the number but also the complexity of available postgraduate programmes. However, there appears to be a lack of standards directing the learning outcomes of such programmes. METHODS: A scientific literature search was conducted for publications reporting on university programmes within implant dentistry, including description of programmes and evaluation of learning outcomes. A separate Internet search was conducted to collect information on existing university programmes as presented on university websites. RESULTS: Implant dentistry has reached a critical mass of an independent, multidisciplinary and vibrant domain of science, which combines knowledge and discovery from many clinical and basic sciences. Many university programmes conclude with a master's or equivalent degree, but there appears to be a great diversity with regard to duration and learning objectives, as well as targeted skills and competences. The importance of implant dentistry has also increased within established specialist training programmes. There was little indication, however, that the comprehensive aspects of implant dentistry are present in all specialist training programmes where implants are being covered. CONCLUSIONS: Although universities should maintain the options of designing academic programmes as they best see fit, it is imperative for them to introduce some form of transparent and comparable criteria, which will allow the profession and the public to relate the degree and academic credentials to the actual skills and competences of the degree holder. With regard to established specialist training programmes, the interdisciplinary and comprehensive nature of implant dentistry needs to be emphasised, covering both surgical and restorative aspects. Finally, implant dentistry is not, at present, a dental specialty. The profession has not reached a consensus as to whether the introduction of a new recognised specialist field is either necessary or desired.

A retrospective analysis of the resorption rate of deproteinized bovine bone as maxillary sinus graft material on cone beam computed tomography.

OBJECTIVES: Graft resorption remains a major disadvantage of the various employed materials in maxillary sinus augmentation. Our aim was to assess the percentage of graft volume reduction in deproteinized bovine bone (DBB) using cone beam computed tomography (CBCT). MATERIALS AND METHODS: A retrospective analysis of 29 augmented sinuses in 19 patients was conducted. The graft material was either DBB alone or DBB mixed with autologous bone chips (80% DBB/20% bone chips). CBCT scans of the augmented sinuses were obtained pre- and post-operatively up to 2-year follow-up. RESULTS: In total, 55 dental implants were placed in the posterior maxillary region following sinus augmentation. The mean height of the alveolar ridge pre-operative was 2.7 ± 1.2 mm and post-operative was 14.13 ± 4.6 mm. The mean percentages of alveolar ridge height reduction were 18.58% (SD14.23%) and 27.62% (SD12.70%), and the mean percentages of graft volume reduction were 19.30% (SD9.19%) and 19.85% (SD9.61%) for DBB and DBB + bone chips, respectively. CONCLUSIONS: The results indicate that DBB graft volume resorption is approximately (20 ± 10%) following 2-year follow-up. CBCT is a useful radiographic tool to follow-up changes in sinus graft volumes.

Dental practitioners and a digital future: an initial exploration of barriers and incentives to adopting digital technologies.

BACKGROUND: Digital technologies are proliferating into dental practices. While their technical attributes have often been studied, it remains unclear why some dentists adopt and use these technologies more than others. AIM To explore the incentives for and barriers against accepting and using digital dental technologies. METHOD: Eleven semi-structured qualitative interviews were conducted with experts in dentistry, dental technology and dental education in the Netherlands. RESULTS: Dentists' acceptance and use of digital technologies are to varying degrees driven by the perceived advantages over analogue methods, perceived influence on treatment quality, dentists' personal and professional orientation, and social influence from peers and external groups. These effects are complemented by personal and dental-practice characteristics. CONCLUSIONS: The findings suggest that there are large differences in motivation to adopt and use digital technologies between early adopters, late adopters and non-adopters, which should be examined in greater detail. We recommend that educators, dentists, and representatives of the dental industry who deal with the diffusion of these technologies take account of dentists' widely different attitudes to digitalisation.

The effect of scan parameters on cone beam CT trabecular bone microstructural measurements of the human mandible.

The objective of this study was to investigate the effect of different cone beam CT scan parameters on trabecular bone microstructure measurements. A human mandibular cadaver was scanned using a cone beam CT (3D Accuitomo 170; J.Morita, Kyota, Japan). 20 cone beam CT images were obtained using 5 different fields of view (4×4 cm, 6×6 cm, 8×8 cm, 10×10 cm and 10×5 cm), 2 types of rotation steps (180° and 360°) and 2 scanning resolutions (standard and high). Image analysis software was used to assess the trabecular bone microstructural parameters (number, thickness and spacing). All parameters were measured twice by one trained observer. Intraclass correlation coefficients showed high intraobserver repeatability (intraclass correlation coefficient, 0.95-0.97) in all parameters across all tested scan parameters. Trabecular bone microstructural measurements varied significantly, especially in smaller fields of view (p = 0.001). There was no significant difference in the trabecular parameters when using different resolutions (number, p = 0.988; thickness, p = 0.960; spacing, p = 0.831) and rotation steps (number, p = 1.000; thickness, p = 0.954; spacing, p = 0.759). The scan field of view significantly influences the trabecular bone microstructure measurements. Rotation steps (180° or 360°) and resolution (standard or high) selections are not relevant.

Diagnostic imaging of trabecular bone microstructure for oral implants: a literature review.

Several dental implant studies have reported that radiographic evaluation of bone quality can aid in reducing implant failure. Bone quality is assessed in terms of its quantity, density, trabecular characteristics and cells. Current imaging modalities vary widely in their efficiency in assessing trabecular structures, especially in a clinical setting. Most are very costly, require an extensive scanning procedure coupled with a high radiation dose and are only partially suitable for patient use. This review examines the current literature regarding diagnostic imaging assessment of trabecular microstructure prior to oral implant placement and suggests cone beam CT as a method of choice for evaluating trabecular bone microstructure.

Cytokine and matrix metalloproteinase expression in fibroblasts from peri-implantitis lesions in response to viable Porphyromonas gingivalis.

BACKGROUND AND OBJECTIVE: To assess inflammatory reactions of fibroblasts in the pathophysiology of peri-implantitis, we compared the pro-inflammatory and matrix-degrading responses of gingival and granulation tissue fibroblasts from periodontally healthy controls, peri-implantitis, and periodontitis lesions to an in vitro challenge with Porphyromonas gingivalis. METHODS: Fibroblasts from periodontally healthy, peri-implantitis and periodontitis donors were challenged with viable P. gingivalis. The inflammatory reactions of fibroblasts were analyzed before and after 6 h P. gingivalis challenge, and 2.5 and 18 h after removal of the challenge. Gene expression and induction of pro-inflammatory mediators, and matrix metalloproteinases (MMPs) were assessed by real-time polymerase chain reaction. Protein expression was measured by enzyme-linked immunosorbent assay. RESULTS: Non-challenged fibroblasts from peri-implantitis and periodontitis lesions expressed higher levels of interleukin (IL)-1ß, IL-8, and monocyte chemotactic protein (MCP)-1 than fibroblasts from periodontally healthy individuals. The P. gingivalis challenge induced expression of IL-1ß, IL-8, IL-6, MCP-1, and MMP-1 in periodontitis and peri-implantitis fibroblasts, but not in fibroblasts from periodontally healthy individuals. MMP-8 expression was higher in non-challenged peri-implantitis fibroblasts than in fibroblasts from periodontally healthy individuals. However, the P. gingivalis challenge downregulated MMP-8 gene expression in peri-implantitis fibroblasts. After removal of the P. gingivalis challenge, peri-implantitis fibroblasts sustained higher induction of IL-1ß, MCP-1, and MMP-1 compared to periodontitis fibroblasts. CONCLUSIONS: Fibroblasts from peri-implantitis and periodontitis lesions gave a more pronounced inflammatory response to the P. gingivalis challenge than fibroblasts from healthy donors. They may therefore be involved in the development of inflammation in peri-implantitis and periodontitis. Moreover, the sustained upregulation of inflammatory mediators and MMP-1 in peri-implantitis fibroblasts may play a role in the pathogenesis of peri-implantitis.

Influence of cone beam CT scanning parameters on grey value measurements at an implant site.

OBJECTIVES: The aim of this study was to determine the grey value variation at the implant site with different scan settings, including field of view (FOV), spatial resolution, number of projections, exposure time and dose selections in two cone beam CT (CBCT) systems and to compare the results with those obtained from a multislice CT system. METHODS: A partially edentulous human mandibular cadaver was scanned by three CT modalities: multislice CT (MSCT) (Philips, Best, the Netherlands), and two CBCT systems: (Accuitomo 170(®), Morita, Japan) and (NewTom 5G(®), QR, Verona, Italy). Using different scan settings 36 and 24 scans were obtained from the Accuitomo and the NewTom, respectively. The scans were converted to digital imaging and communications in medicine 3 format. The analysis of the data was performed using 3Diagnosys(®) software (v. 3.1, 3diemme, Cantù, Italy) and Geomagic studio(®) 2012 (Morrisville, NC). On the MSCT scan, one probe designating the site for pre-operative implant placement was inserted. The inserted probe on MSCT was transformed to the same region on each CBCT scan using a volume-based three-dimensional registration algorithm. The mean voxel grey value of the region around the probe was derived separately for each CBCT. The influence of scanning parameters on the measured mean voxel grey values was assessed. RESULTS: Grey values in both CBCT systems significantly deviated from Hounsfield unit values measured with MSCT (p = 0.0001). In both CBCT systems, scan FOV and spatial resolution selections had a statistically significant influence on grey value measurements (p = 0.0001). The number of projections selection had a statistically significant influence in the Accuitomo system (p = 0.0001) while exposure time and dose selections had no statistically significant influence on grey value measurements in the NewTom (p = 0.43 and p = 0.37, respectively). CONCLUSIONS: Grey-level values from CBCT images are influenced by device and scanning settings.

The effect of scan parameters on cone beam CT trabecular bone microstructural measurements of human mandible.

The objective of this study was to investigate the effect of different cone beam CT scan parameters on trabecular bone microstructure measurements. A human mandibular cadaver was scanned using a cone beam CT (3D Accuitomo 170; J.Morita, Kyota, Japan). 20 cone beam CT images were obtained using 5 different fields of view (4×4 cm, 6×6 cm, 8×8 cm, 10×10 cm and 10×5 cm), 2 types of rotation steps (180° and 360°) and 2 scanning resolutions (standard and high). Image analysis software was used to assess the trabecular bone microstructural parameters (number, thickness and spacing). All parameters were measured twice by one trained observer. Intraclass correlation coefficients showed high intraobserver repeatability (intraclass correlation coefficient, 0.95­0.97) in all parameters across all tested scan parameters. Trabecular bone microstructural measurements varied significantly, especially in smaller fields of view (p = 0.001). There was no significant difference in the trabecular parameters when using different resolutions (number, p = 0.988; thickness, p = 0.960; spacing, p = 0.831) and rotation steps (number, p = 1.000; thickness, p = 0.954; spacing, p = 0.759). The scan field of view significantly influences the trabecular bone microstructure measurements. Rotation steps (180° or 360°) and resolution (standard or high) selections are not relevant.