Irene H. A. Aartman

Accuracy of trabecular bone microstructural measurement at planned dental implant sites using cone-beam CT datasets

OBJECTIVEnCone-beam CT (CBCT) images are infrequently utilized for trabecular bone microstructural measurement due to the systems limited resolution. The aim of this study was to determine the accuracy of CBCT for measuring trabecular bone microstructure in comparison with micro CT (μCT).nnnMATERIALS AND METHODSnTwenty-four human mandibular cadavers were scanned using a CBCT system (80 μm) and a μCT system (35 μm). Three bone microstructural parameters trabecular number (Tb.N), thickness (Tb.Th) and separation (Tb.Sp) were assessed using CTAn imaging software.nnnRESULTSnIntraclass correlation coefficients (ICC) showed a high intra-observer reliability (≥ 0.996) in all parameters for both systems. The Pearson correlation coefficients between the measurements of the two systems were for Tb.Th 0.82, for Tb.Sp 0.94 and for Tb.N 0.85 (all Ps<0.001). The Bland and Altman plots showed strongest agreement in Tb.N (-0.37 μm) followed by Tb.Th (1.6 μm) and Tb.Sp (8.8 μm).nnnCONCLUSIONSnCone-beam CT datasets can be used to evaluate trabecular bone microstructure at dental implant sites. The accuracy for measuring Tb.N was the best followed by Tb.Th and Tb.Sp.

Volumetric Changes in Apical Radiolucencies of Endodontically Treated Teeth Assessed by Cone-beam Computed Tomography 1 Year after Orthograde Retreatment

INTRODUCTIONnCone-beam computed tomography (CBCT) allows us to assess in 3 dimensions the location and size of periapical radiolucencies. We aimed to assess by CBCT scans the volumetric changes of periapical radiolucencies in endodontically treated teeth 1 year after orthograde retreatment.nnnMETHODSnForty-five root-filled teeth with persistent apical periodontitis requiring endodontic orthograde retreatment from 37 individuals were included in the study. The research protocol was approved by the VU University Medical Center Amsterdam ethics committee (2007/265), and the participants signed a letter of consent. We made 2 CBCT scans for every patient, the first one before retreatment and the second one a year later. Two observers measured independently the volume of radiolucencies on CBCT images by using the AMIRA software. The intraclass correlation coefficient was used to evaluate interobserver agreement, and the Wilcoxon signed rank test was used to assess pretreatment and post-treatment volume size.nnnRESULTSnThe intraclass correlation coefficients were 0.994 and 0.998 for the scans before retreatment and 1 year after, respectively. The recall rate was 78% for the teeth and 73% for the patients. The volumetric change in periapical radiolucencies 1 year after retreatment was statistically significant (zxa0=xa0-3.112, P < .005). The volume of periapical radiolucencies reduced in 20 teeth (57%), remained unchanged in 8 (23%), and increased in 7 (20%).nnnCONCLUSIONSnOne year after endodontic orthograde retreatment, the volume of periapical radiolucencies reduced significantly in 57% of the teeth.

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 (4×4u2009cm, 6×6u2009cm, 8×8u2009cm, 10×10u2009cm and 10×5u2009cm), 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 (pxa0=xa00.001). There was no significant difference in the trabecular parameters when using different resolutions (number, pxa0=xa00.988; thickness, pxa0=xa00.960; spacing, pxa0=xa00.831) and rotation steps (number, pxa0=xa01.000; thickness, pxa0=xa00.954; spacing, pxa0=xa00.759). 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.

Influence of object location in different FOVs on trabecular bone microstructure measurements of human mandible: a cone beam CT study

The aim of this study was to assess the influence of different object locations in different fields of view (FOVs) of two cone beam CT (CBCT) systems on trabecular bone microstructure measurements of a human mandible. A block of dry human mandible was scanned at five different locations (centre, left, right, anterior and posterior) using five different FOVs of two CBCT systems (NewTom™ 5G; QR Verona, Verona, Italy and Accuitomo 170; Morita, Kyoto, Japan). Image analysis software (CTAn software v. 1.1; SkyScan, Kontich, Belgium) was used to assess the trabecular bone microstructural parameters (thickness, Tb.Th; spacing, Tb.Sp; number, Tb.N; bone volume density, BV/TV). All measurements were taken twice by one trained observer. Tb.Th, Tb.Sp and Tb.N varied significantly across different FOVs in the NewTom 5G (pu2009<u20090.001) and the Accuitomo 170 (pu2009<u20090.001). For location, a significant difference was observed only when measuring BV/TV (pu2009=u20090.03) using the NewTom 5G. The trabecular bone microstructural measurements obtained from CBCT systems are influenced by the size of FOVs. Not all trabecular bone parameters measured using different CBCT systems are affected when varying the object location within the FOVs.

Association between extra- and intracranial calcifications of the internal carotid artery: a CBCT imaging study

OBJECTIVESnThis study aimed to evaluate the association between the extracranial and intracranial calcification depiction of the internal carotid artery (ICA), incidentally found in CBCT examinations in adults, and to discuss the conspicuous clinical implications.nnnMETHODSnOut of a series of 1085 CBCT examinations, 705 CBCT scans were selected according to pre-defined criteria. The extra- and intracranial calcifications depicted along the course of the ICA were documented according to a comprehensive set of descriptive criteria.nnnRESULTSnIn total, 799 findings were detected, 60.1% (nu2009=u2009480) were intracranially and 39.9% (nu2009=u2009319) were extracranially allocated. The χ(2) test showed associations between all variables (pu2009<u20090.001). Also, most of the combinations of variables showed statistically significant results in the McNemars test (pu2009<u20090.001).nnnCONCLUSIONSnWe found that a significant correlation exists between extra- and intracranial calcifications of the ICA. It is clear that in cases of the presence of a calcification in the ICA extracranially, the arterys intracranial portion has an increased risk of showing the same findings. CBCT imaging is widely used as a diagnostic tool, thus, our results contribute to the identification of a subgroup of patients who should undergo further medical evaluation of the atherosclerosis of the ICAs.

Adoption and use of digital technologies among general dental practitioners in the Netherlands

Objectives To investigate (1) the degree of digital technology adoption among general dental practitioners, and to assess (2) which personal and practice factors are associated with technology use. Methods A questionnaire was distributed among a stratified sample of 1000 general dental practitioners in the Netherlands, to measure the use of fifteen administrative, communicative, clinical and diagnostic technologies, as well as personal factors and dental practice characteristics. Results The response rate was 31.3%; 65.1% replied to the questionnaire on paper and 34.9% online. Each specific digital technology was used by between 93.2% and 6.8% of the dentists. Administrative technologies were generally used by more dentists than clinical technologies. Dentists had adopted an average number of 6.3±2.3 technologies. 22.5% were low technology users (0 to 4 technologies), 46.2% were intermediate technology users (5 to 7 technologies) and 31.3% were high technology users (8 to12 technologies). High technology users more frequently had a specialization (p<0.001), were younger on average (p=0.024), and worked more hours per week (p=0.003) than low technology users, and invested more hours per year in professional activities (p=0.026) than intermediate technology users. High technology use was also more common for dentists working in practices with a higher average number of patients per year (p<0.001), with more dentists working in the practice (p<0.001) and with more staff (p<0.001). Conclusion With few exceptions, all dentists use some or a substantial number of digital technologies. Technology use is associated with various patterns of person-specific factors, and is higher when working in larger dental practices. The findings provide insight into the current state of digital technology adoption in dental practices. Further exploration why some dentists are more reluctant to adopt technologies than others is valuable for the dental profession’s agility in adjusting to technological developments.

A Systematic Review on Immediate Loading of Implants Used to Support Overdentures Opposed by Conventional Prostheses: Factors That Might Influence Clinical Outcomes.

PURPOSEnDifferent treatment protocols in terms of number, diameter, and suprastructure design have been proposed for immediately loaded implants that are used to support mandibular overdentures opposed by maxillary conventional dentures. The aim of this study was to investigate the influence of these protocols on survival rates as well as clinical and prosthodontic outcomes.nnnMATERIALS AND METHODSnSeveral electronic databases were searched for all relevant articles published from 1966 to June 2014. Only randomized controlled trials and prospective studies with a minimum follow-up of 12 months were selected. The primary outcomes of interest were the success and survival rates of the implants. Prosthodontic complications were also evaluated.nnnRESULTSnFourteen studies fulfilled the inclusion criteria. Of the studies identified, nine were randomized controlled trials and five were prospective studies. The mean follow-up period was 3 years or less for the vast majority of the studies. The reported survival and success rates were comparable to that of conventional loading for most of the included studies. No specific immediate loading protocol seemed to perform better in terms of clinical and prosthodontic outcomes.nnnCONCLUSIONnImmediate loading protocols of mandibular overdentures seem to be a viable alternative to conventional loading. It was not possible to recommend a specific treatment protocol related to the number, diameter of the implants, and attachment system used. Long-term, well-designed studies comparing different immediate loading modalities could help to establish a protocol that delivers the most clinically predictable, efficient, and cost-effective outcome for edentulous patients in need of implant overdentures.

Implant mandibular overdentures retained by immediately loaded implants : A 1-year randomized trial comparing patient-based outcomes between mini dental implants and standard-sized implants

PURPOSEnThe aim of this 1-year randomized trial was to determine the stability and the magnitude of the effect of converting patients conventional mandibular dentures to implant overdentures (IODs) on their satisfaction and oral health-related quality of life (OHRQoL). The IODs were retained either with two immediately loaded interconnected standard-diameter implants or with four immediately loaded mini dental implants (MDIs).nnnMATERIALS AND METHODSnFifty completely edentulous subjects complaining about insufficient retention of their mandibular dentures were randomly assigned to two groups; 25 patients received IODs retained with four MDIs and 25 patients received IODs retained with two standard-sized tissue level (STL) interconnected implants. All IODs were opposed by conventional maxillary dentures. Patients rated their satisfaction on a 100-mm visual analog scale (VAS) and their quality of life on a denture-specific short version of the oral health impact profile (OHIP-20) before assignment, and after 3 and 12 months. A two-way mixed analysis of variance (ANOVA) was conducted to assess the change in time and its interaction with treatment mode on patients overall satisfaction ratings, the total OHIP-20, and their specific domain scores.nnnRESULTSnImmediate loading was possible for all the patients who received the MDIs. By contrast, the immediate loading protocol could be followed for only 15 of the patients allocated to the STL implant group. For the remaining patients, a delayed loading protocol was applied. There was a significant improvement in patients general satisfaction between baseline and 3 months and between baseline and 12 months postoperatively (F2,44 = 81.006, P < .001). This increase did not differ between the treatment groups (F4,90 = 1.838, P = .128). The results also showed a decrease in mean overall OHIP score (F2,43 = 46.863, P < .001) between baseline and 3 months and between baseline and 12 months postoperatively, indicating a higher level of OHRQoL. In addition, patients scored lower 3 and 12 months after treatment than at baseline for all seven domains. This decrease did not differ between the treatment groups (F4,88 = 0.608, P = .658).nnnCONCLUSIONnThe results suggested that in terms of patient-based outcomes, mandibular overdentures retained by immediately loaded MDIs can offer an improvement of equal magnitude with that achieved by overdentures retained by standard-sized implants.

Implant Mandibular Overdentures Retained by Immediately Loaded Implants: A 1-Year Randomized Trial Comparing the Clinical and Radiographic Outcomes Between Mini Dental Implants and Standard-Sized Implants

PURPOSEnThe aim of this 1-year randomized trial was to evaluate and compare the clinical and radiographic performance of four immediately loaded mini dental implants (MDIs) and two immediately loaded standard-sized tissue-level (STL) implants, placed in the interforaminal region of the mandible and used to retain mandibular overdentures (IODs) in completely edentulous patients.nnnMATERIALS AND METHODSnA total of 50 completely edentulous patients wearing conventional maxillary dentures and complaining about insufficient retention of their mandibular dentures were divided into two groups; 25 patients received four MDIs and 25 patients received two STL implants. The marginal bone loss (MBL) at the mesial and distal sides of each implant was assessed by means of standardized intraoral radiographs after a period of 1 year. Implant success and survival rates were also calculated.nnnRESULTSnImmediate loading was possible for all patients in the first group. In the second group, an immediate loading protocol could not be applied for 10 patients. These patients were treated with a delayed loading protocol. A mean MBL of 0.42 ± 0.56 mm for the MDIs and 0.54 ± 0.49 mm for the immediately loaded STL implants was recorded at the end of the evaluation period. There was no statistically significant difference between the MDIs and the immediately loaded STL implants. Two MDIs failed, resulting in a survival rate of 98%. The success rate was 91%. For the immediately loaded conventional implants, the survival rate was 100% and the success rate 96.7% after 1 year of function. However, in 10 patients, the immediate loading protocol could not be followed.nnnCONCLUSIONnConsidering the limitations of this short-term clinical study, immediate loading of four unsplinted MDIs or two splinted STL implants to retain mandibular overdentures seems to be a feasible treatment option. The marginal bone level changes around the MDIs were well within the clinically acceptable range.