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Objectives: This study investigates effects of surgical guide manufacturing process on 3D transfer accuracy of planned dental implant position, using three production methods: additive 3D‐printed (3DF), subtractive milled (MF), and analog laboratory fabricated templates (LF). Material and Methods: Implant position for a single‐tooth gap (#26) planned digitally. 3DF and MF templates were designed digitally, while LF templates were analogously created. For each manufacturing type, 10 surgical guides were fabricated. Each guide was used for template‐guided implant placement in model replicas. For evaluation of implant placement, cone beam computed tomography scans of all implanted models were superimposed, and implant positions were determined. Deviations at implant shoulder/apex were measured, and median and inter‐quartile range (IQR) were determined for mesio‐distal, oro‐facial, coronal apico, 3D spaces, and angles. Results: At implant shoulder, vertical components dominated position deviations (up to 1.04 mm, IQR 0.28 mm for 3DF). Horizontal deviations were much lower (mesio‐distally up to 0.38 mm, IQR 0.36 mm (LF)). Implant apex shows similar vertical deviations, while horizontal deviations clearly increased compared to shoulder, especially in mesio‐distal direction. Median angular deviations were between 2.1° (IQR 2.0 mm, max. 4.2°) for 3DF and 3.3° (IQR 1.9 mm, max. 5.3°) for MF. No statistical differences were found between manufacturing types (Kruskal–Wallis test, p =.05). Conclusions: The study showed the method of implant guide fabrication did not affect the accuracy of implant placement within the limits of an in vitro environment. All methods resulted in implant placement which did not exceed the accepted safety deviation envelope (1.5–2.0 mm). [ABSTRACT FROM AUTHOR]

Objectives: The objective of the study was to evaluate the radiographic changes in sinus mucosal thickness (SMT) in patients with mucosal thickening of odontogenic origin after maxillary molar extraction and lateral sinus augmentation with simultaneous surgical drainage and implant placement. Materials and Methods: Forty‐six patients were included in this study. The changes in SMT were evaluated using cone‐beam computed tomography images produced at four time points: before extraction (T0), before surgery (T1), immediately after surgery (T2), and after prosthesis delivery (T3), and statistical differences between time points were analyzed. The changes in SMT and augmented bone height (ABH) regarding the reason of extraction, smoking, ostial patency, and the presence of postoperative sinusitis were also evaluated. Results: Over time points, SMT gradually decreased (T0: 19.44 ± 9.22 mm, T1: 15.10 ± 8.89 mm, T2: 8.42 ± 6.01 mm, and T3: 4.16 ± 4.91 mm) (p <.05). Five out of 6 patients with ostial obstruction at T1 presented ostial patency at T3. Two patients developed postoperative sinusitis but recovered with medication. Ostial patency at T1, SMT at T1, and reason of extraction did not statistically significantly influence SMT at T3. SMT at T1 had no statistically significant impact on ABH change between T2 and T3. Conclusion: Sinus mucosal thickness was gradually reduced by extraction of compromised teeth and drainage during lateral sinus augmentation. The drainage contributed more to the reduction in SMT. [ABSTRACT FROM AUTHOR]

Aim: To validate in vitro the accuracy of a novel method for bone augmentation of horizontal alveolar bone defects with the help of a surgical guide. Material and methods: Six cone‐beam computed tomography scans of patients requiring horizontal bone augmentation were segmented and 3D printed. Two surgeons performed the bone augmentation surgery twice for each case on 3D‐printed models, using either a conventional or guided protocol. Each surgeon virtually planned the desired graft shape beforehand. The resulting grafts were compared linearly and volumetrically to the plan; graft density and surgical time were also analyzed. Results: There was significantly less graft volume outside the planned volume with the guided protocol (36.8% ± 14.1 vs. 19.6% ± 12.3, p <.01). The use of a guide increased graft accuracy at several measurement points, resulting in less overfill when using the guided protocol (1.7 ± 1.7 mm at the most coronal point, 0.2 mm ± 1.4 at 25%, 0.0 mm ± 0.9 at 50%, 0.1 mm ± 1.1 at 75%, and 0.4 mm ± 1.4 apically). Graft thickness was increased 1 mm coronally from the planned graft (2.8 mm ± 2.3 vs. 1.8 mm ± 2.2, p =.04). Surgical time increased significantly when using a guide (a difference of 2 m 26 s). Conclusion: The technique, tested here in vitro, allows surgeons to improve the accuracy of the resulting graft shape, to better compact material in the coronal portion of the graft, and to reduce the amount of graft material placed outside the planned volume. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the in vitro diagnostic accuracy of low‐dose cone‐beam computed tomography (LD‐CBCT) for the detection, classification, and measurement of peri‐implant bone lesions. Material and methods: Titanium dental implants with all‐ceramic single crowns (n = 24) were inserted into bovine bone. At twelve implants, four types of peri‐implant bone lesions were created. Radiographic imaging was performed using three techniques: LD‐CBCT, high‐definition CBCT (HD‐CBCT), and intraoral radiography (IR). The datasets were presented twice to four observers in a random order. Diagnostic accuracy was measured by calculating sensitivity and specificity, and analyzed using the McNemar's test at a significance level of 0.05. Absolute agreement between the defect sizes was assessed by means of intraclass correlation coefficients (ICC). Results: For all three techniques, diagnostic accuracy and reliability for the detection of defects were almost perfect. The following order was found for classification of the different defect types (sensitivity/specificity): HD‐CBCT (0.96/0.99) > LD‐CBCT (0.93/0.98) > IR (0.71/0.95). No significant difference was found between the two CBCT techniques. Their performance was superior to that of IR. With regard to absolute agreement of defect size, LD‐CBCT agreement with HD‐CBCT (ICC, 95% confidence interval) was slight for defect depth (0.342, 0.181–0.625) and substantial for defect width (0.911, 0.775–0.963). Conclusion: Intraoral radiography is useful for detecting peri‐implant bone lesions. LD‐CBCT provides additional information regarding the geometry of defects. The even higher diagnostic accuracy of the HD‐CBCT protocol tested needs to be carefully weighed against its radiation dose, which is 14 times higher than that of LD‐CBCT. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The aim of this study was to compare bone block grafts fixed at a distance (BBG‐D) with the SonicWeld Rx shell technique (Poly‐D‐L‐Lactide foil fixed at a distance, augmented with autogenous and deproteinized bovine bone particles (SWST)) for lateral alveolar ridge augmentation. Methods: In this single‐blinded, randomized, controlled trial, 30 patients with a bucco‐palatal bone width of ≤3 mm were randomized into the treatment groups: “BBG‐D” and “SWST”. Bone width was measured with cone beam computed tomography (CBCT). One implant was placed at each grafted site. Frequencies of complications, bone gain and bone resorption in the CBCT were assessed as outcomes. Results: Fifteen sites were augmented in each treatment group. One graft (7%) in the BBG‐D group and five (33%) in the SWST group were lost (p = 0.17). In the SWST group, two implants (20%) were lost and none in the BBG‐D group (p = 0.18). The rate of pooled severe complications (loss of graft and/or implant) was different (p = 0.035). Five (33%) wound dehiscences happened in the SWST group and none in the BBG‐D group (p = 0.042). Seven (47%) nonsevere complications (wound dehiscence, inflammation, transient nerve injury) happened in the SWST group and one (7%) in the BBG‐D group (p = 0.035). At the one‐year evaluation, there were no significant differences in bone loss at the mesial, distal or buccal implant shoulder between treatment groups. Conclusions: Within the limitations of this study, the BBG‐D method remains the gold standard for lateral alveolar ridge augmentation compared to the shell technique because of the lower complication rates. [ABSTRACT FROM AUTHOR]

Purpose The aim of the study was to analyze the accuracy of measuring the cortical bone thickness using a combination of low- and high-frequency ultrasound ( US) compared with cone-beam computed tomography ( CBCT) and using stereomicroscopy as reference method. Material and Methods Ten jawbone models were prepared using bovine ribs and porcine gingiva. A dental implant was placed in each model. All models were investigated by US, CBCT, and stereomicroscopy. The cortical bone thickness was measured directly above and 4 mm beside the implant with each method in different slices. Results The median deviation of US measurements compared to the reference method was 0.23 mm. The CBCT method was slightly more accurate (median percent deviation of 9.2%) than the US method (10.3%). However, US measurements directly above the implant were more accurate than CBCT measurements with a median percent deviation of 10.5% for US vs. 11.8% for CBCT. Conclusion Ultrasound showed a high potential to supplement CBCT for measurements of the cortical bone thickness. [ABSTRACT FROM AUTHOR]

Background Buccal plate thickness is of clinical importance in treatment planning for implants. The purpose of this study was to evaluate the buccal plate thickness in posterior dentate areas of both the maxilla and mandible using cone beam computed tomography in order to estimate the approximate distributions of this anatomic variable. Methods Two hundred and sixty-five subjects were included for a total of nine hundred and thirty-four roots assessed by cone beam computed tomography. CBCT scans were taken and evaluated at the ideal buccolingual cross-sections of each root at 1 mm, 3 mm, and 5 mm apical to the alveolar crest to measure buccal plate thickness. Data are reported by geometric means and 95% confidence intervals. Results Both arches demonstrated increasing buccal plate thickness from anterior to posterior. Maxillary teeth had a significant decrease in thickness from coronal to apical along the tooth root ( P < 0.001), except at second molars. The first premolar and mesial root of the first molar were significantly thinner than all other roots in the maxilla. Conversely, the mandible demonstrated a significant increase in buccal plate thickness from coronal to apical ( P < 0.001). The premolars were significantly thinner than all other roots. Age and sex were found to have limited impact on buccal plate thickness in both arches. Conclusions Buccal plate thickness is highly dependent upon the arch position, tooth location, and measurement point, but age and sex have limited impact. [ABSTRACT FROM AUTHOR]

Objectives To evaluate the accuracy of measuring peri-implant buccal bone when using three different computed tomography devices. Materials and methods Sixty tissue-level or bone-level dental implants were placed in bovine ribs with either buccal bone full coverage, dehiscence or fenestration. For each site, the distance from the bone defect to the implant neck and the buccal bone thickness 1 mm apical to the crest were measured using a calliper. Subsequently, all sites were scanned in a reproducible position using a multi-slice computed tomography ( CT) (Brightspeed, voxel size 0.625 mm) and two cone-beam computed tomography devices (i-CAT NG, voxel size 0.3 mm and Newtom VGi, voxel size 0.2 mm). Bone thickness was measured on images from the three systems similar to direct measurements and differences were evaluated. Factors that could influence the buccal bone identification were assessed by multiple binary logistic regression. Results Buccal bone ranged from 0.1 mm to 2.75 mm in thickness and was not visible in 68%, 63% and 60% of cases when using CT, i-CAT and Newtom, respectively. For each mm of bone thickness increment, the odds of radiographic identification increased by 30.6 ( P < 0.001). Bone defects negatively affected radiographic visibility ( P < 0.05). All devices underestimated bone dimensions although differences among them were not significant. Conclusions Within these experimental conditions, the investigated devices have equivalent low accuracy in diagnosing peri-implant buccal bone. Accuracy was significantly influenced by buccal bone thickness, especially if <1 mm, and in presence of peri-implant marginal defects. [ABSTRACT FROM AUTHOR]

Aim To associate the dimension of the facial bone wall with clinical, radiological, and patient-centered outcomes at least 10 years after immediate implant placement with simultaneous guided bone regeneration in a retrospective study. Material and methods Primary endpoint was the distance from the implant shoulder ( IS) to the first bone-to-implant contact ( IS- BIC10y). Secondary endpoints included the facial bone thickness ( BT10y) 2, 4, and 6 mm apical to the IS, and the implant position. At baseline, the horizontal defect width ( HDWBL) from the implant surface to the alveolar wall was recorded. At recall, distance from the IS to the mucosal margin ( IS- MM10y), degree of soft tissue coverage of the mesial and distal aspects of the implants ( PISm10y, PISd10y; Papilla Index), pocket probing depth ( PPD10y), and patient-centered outcomes were determined. Width of the keratinized mucosa ( KM), Full-Mouth Plaque and Bleeding Score ( FMPS, FMBS) were available for both time points. Results Of the 20 patients who underwent immediate implant placement with simultaneous guided bone regeneration and transmucosal healing, nine males and eight females with a median age of 62 years (42 min, 84 max) were followed up for a median period of 10.5 y (min 10.1 max 11.5). The 10-year implant survival rate was 100%. Multivariate regression analysis revealed a correlation of the IS- BIC10y, controlled for age and gender, with four parameters: HDWBL ( P = 0.03), KMBL-10 ( P = 0.02), BT10 4 mm ( P = 0.01), and BT10 6 mm ( P = 0.01). Conclusion Within the conditions of the present study, the horizontal defect width was the main indicator for the vertical dimension of the facial bone. The facial bone dimension was further associated with a reduction in the width of the keratinized mucosa and the dimension of the buccal bone. [ABSTRACT FROM AUTHOR]

Aim The aim of this study was to test whether or not the intensity of artifacts around implants in cone-beam computed tomography ( CBCT) differs between titanium, titanium-zirconium and zirconium dioxide implants. Materials and methods Twenty models of a human mandible, each containing one implant in the single-tooth gap position 45, were cast in dental stone. Five test models were produced for each of the following implant types: titanium 4.1 mm diameter (Ti4.1), titanium 3.3 mm diameter (Ti3.3), titanium-zirconium 3.3 mm diameter (TiZr3.3) and zirconium dioxide 3.5-4.5 mm diameter (ZrO3.5-4.5) implants. For control purposes, three models without implants were produced. Each model was scanned using a CBCT device. Gray values ( GV) were recorded at eight circumferential positions around the implants at 0.5 mm, 1 mm and 2 mm from the implant surface ( GVTest). GV were assessed in the corresponding volumes of interest ( VOI) in the control models without implants ( GVControl). Differences of gray values (Δ GV) between GVTest and GVControl were calculated as percentages. One-way ANOVA and post hoc tests were applied to detect differences between implant types. Results Mean Δ GV for ZrO3.5-4.5 presented the highest absolute values, generally followed by TiZr3.3, Ti4.1 and Ti3.3 implants. The differences of Δ GV between ZrO3.5-4.5 and the remaining groups were statistically significant in the majority of the VOI ( P ≤ 0.0167). Δ GV for TiZr3.3, Ti4.1 and Ti3.3 implants did not differ significantly in the most VOI. For all implant types, Δ GV showed positive values buccally, mesio-buccally, lingually and disto-lingually, whereas negative values were detected mesially and distally. Conclusions Zirconium dioxide implants generate significantly more artifacts as compared to titanium and titanium-zirconium implants. The intensity of artifacts around zirconium dioxide implants exhibited in average the threefold in comparison with titanium implants. [ABSTRACT FROM AUTHOR]

Aim To examine the literature on novel digital imaging techniques for the assessment of outcomes in oral rehabilitation with dental implants. Material and methods An electronic search of Medline and Embase databases including studies published prior to 28th December 2014 was performed and supplemented by a manual search. A synthesis of the publications was presented describing the use of computed tomography ( CT), magnetic resonance imaging ( MRI), ultrasonography, optical scanning, spectrophotometry or optical coherence tomography ( OCT) related to the outcome measures in implant therapy. Results and conclusions Most of the digital imaging techniques have not yet sufficiently been validated to be used for outcome measures in implant dentistry. In clinical research, cone beam CT ( CBCT) is increasingly being used for 3D assessment of bone and soft tissue following augmentation procedures and implant placement. Currently, there are no effective methods for the reduction of artifacts around implants in CBCT. Optical scanning is being used for the 3D assessment of changes in the soft tissue contour. The combination of optical scan with pre-operative CBCT allows the determination of the implant position and its spatial relation to anatomical structures. Spectrophotometry is the method most commonly used to objectively assess the color match of reconstructions and peri-implant mucosa to natural dentition and gingiva. New optical imaging techniques may be considered possible approaches for monitoring peri-implant soft tissue health. MRI and ultrasonography appear promising non-ionizing radiation imaging modalities for the assessment of soft tissue and bone defect morphologies. Optical scanners and OCT may represent efficient clinical methods for accurate assessment of the misfit between the reconstructions and the implants. [ABSTRACT FROM AUTHOR]

Objectives To implement and evaluate the accuracy of a prototype dynamic computer-assisted surgery ( CAS) system for implant osteotomy preparation and compare its accuracy vs. three commercial static CAS systems and the use of an acrylic stent. Material and methods Eight osteotomies were prepared in radiopaque partially edentulous mandible and maxilla typodonts. After cone-beam CT acquisition, DICOM files were imported into a prototype dynamic, and three static CAS systems (NobelClinician, Simplant, and CoDiagnostiX). Implant placements were planned to replicate the existing osteotomies and respective guides were requisitioned, along with one laboratory-made acrylic guide. The eight osteotomies per jaw were transferred to one typodont pair mounted in a manikin in a clinical setting and the process was repeated for four additional pairs. The 80 (two jaws × eight holes × five pairs) osteotomies were filled with radiopaque cement in-between the testing series. Three clinicians experienced with the use of the static CAS softwares used in this study prepared each 400 (80 holes × five modalities) osteotomies. One clinician repeated the experiment twice, resulting in a total of 2000 (five clinicians × 400) osteotomies. The lateral, vertical, total, and angular deviations of the actual vs. the original osteotomies in the master typodonts were measured using stereo optical tracking cameras. Linear regression statistics using generalized estimating equations were used for comparisons between the five modalities and omnibus chi-square tests applied to assess statistical significance of differences. Results The prototype dynamic CAS system was as accurate as other implant surgery planning and transfer modalities. The dynamic and static CAS systems provide superior accuracy vs. a laboratory-made acrylic guide, except vertically. Both dynamic and static CAS systems show on average <2 mm and 5 degrees error. Large deviations between planned and actual osteotomies were occasionally observed, which needs to be considered in clinical practice. Conclusions The prototype dynamic CAS system was comparably accurate to static CAS systems. [ABSTRACT FROM AUTHOR]

Aim To present 10-year cone beam CT ( CBCT) data on the fate of buccal bone at single-tooth implants placed early, delayed, or late after tooth extraction. Material and methods Sixty-three of 72 patients, originally randomly allocated to three equal-size groups, received a single-tooth implant on average 10 days (Ea; N = 22), 3 months (De; N = 22), or 1.5 years (La; N = 19) after tooth extraction. Healing abutments were mounted after a 3-month period of submerged healing and metalceramic crowns were cemented after one additional month. At the second stage surgery, presence of buccal bone defects (dehiscences or intrabony) and their dimensions were registered. CBCT scans recorded with a Scanora® 3D unit and standardized periapical ( PA) radiographs of the implants were obtained at the 10-year control. Interproximal bone levels (i.e., the distance from the implant platform to the first bone-to-implant contact; BIC) measured in CBCT image sections and PA were compared, and the buccal bone level was determined in the CBCT images. Results Two Ea and one De implants failed to osseointegrate. Forty-nine patients attended the 10-year control and due to poor quality of 5 CBCT scans, useful CBCT images were available from 44 patients (Ea:12, De:17, La:15). No significant differences between CBCT and PA images in measurements of the interproximal bone levels were observed. Ten years after implant placement, BIC at the buccal aspect was located on average 2 mm apically to the implant platform (2.39 ± 1.06 mm [median = 2.36] for Ea, 2.22 ± 0.99 mm [median = 2.16] for De, and 1.85 ± 0.65 mm [median = 1.95] for La implants) with no significant difference among the groups ( P = 0.20). Mean buccal bone level ( bBL) for implants with an intrabony or a dehiscence defect at second stage surgery was 2.51 ± 1.12 mm [median = 2.70] and 2.84 ± 0.70 mm [median = 2.79], respectively, while 1.78 ± 0.74 mm [median = 1.93] for the implants with no defect. The difference in bBL between the implants without a defect and those with a dehiscence was significant at 10 years ( P = 0.0005). Conclusion Time of placement of single-tooth implants after tooth extraction did not significantly influence the peri-implant buccal bone level, while presence of a buccal bone dehiscence at second stage surgery resulted in significantly more apically located BIC buccally at 10 years. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this controlled clinical study was to compare a polyethylene glycol membrane (PEG) used for bone regeneration of peri-implant defects to a collagen membrane with respect to implant survival rate, dimensions of buccal peri-implant bone and mucosa. Materials and methods: Thirty-seven patients who received single tooth implants with simultaneous guided bone regeneration (GBR) in the posterior maxilla or mandible were enrolled in the study. Intra-operative heights of bone defects were assessed prior to bone augmentation. The defects were augmented with xenogenic bone mineral and randomly covered either with a porcine collagen membrane (control) or with a PEG membrane (test). Five years after implant placement, clinical evaluation and cone beam computed tomography (CBCT) scans were performed. Remaining height of bone defect, horizontal bone thickness, level of mucosal margin, and mucosal thickness were assessed in CBCT images. The difference of height of bone defect at implant placement and at 5-year follow-up was calculated. The differences between the two groups were analyzed using two-sided t-test and Mann-Whitney U-test. Results: After 5 years, 32 patients could be included and exhibited an implant survival rate of 100% for both groups. The buccal vertical bone gain between implant placement and 5-year follow-up amounted at 4.3 ± 1.5 (SD) mm and 4.8 ± 2.6 (SD) mm for the control and the test group, respectively (P = 0.493). Neither the bone height nor the thickness reached statistical significant differences between the two groups. The distance between mucosal margin and implant shoulder resulted in 0.8 ± 0.7 (SD) mm in the control and 0.5 ± 0.8 (SD) mm in the test group (P = 0.198). The mucosal thickness reached 1.4 ± 0.5 (SD) mm in the control and 1.3 ± 0.3 (SD) mm in the test group (P = 0.715). There were no significant correlations between height of bone defect at baseline and at follow-up examination and between different 5-year parameters. Conclusion: A polyethylene glycol membrane used for bone regeneration of peri-implant defects performed as successfully as a collagen membrane with respect to implant survival rate and dimensions of the buccal peri-implant bone and mucosa after 5 years. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to explore the efficacy of bone density value derived from cone beam computed tomography (CBCT) by evaluating its correlation with implant stability parameters including insertion torque value (ITV) and radiofrequency analysis in relation to different clinical variables including location, gender, age, bone quality, and implant diameter. Material and Methods: A total of 65 implants were placed in 17 patients. The bone densities of implant recipient sites were preoperatively recorded using CBCT. Bone quality was subjectively assessed, which depends on the stiffness of the jawbone according to the Lekholm and Zarb index during drilling procedure. The maximum ITV of each implant was recorded useing a digital torque meter during implant placement. Resonance frequency measurements were taken using an Osstell Mentor immediately after implant placement. Data were analyzed statistically. Results: The mean bone density, insertion torque, and implant stability quotient values of all implants were 556 ± 80, 37.4 ± 3.3 Ncm, and 73.8 ± 7.2, respectively. Statistically significant correlations were found between bone density values from CBCT and implant stability parameters in relation to all variables. Conclusion: Bone density assessment using CBCT is an efficient method and significantly correlated with implant stability parameters and Lekholm and Zarb index. Thus, it is possible to predict initial implant stability and possibility of immediate or early loading using CBCT scans prior to implant placement. [ABSTRACT FROM AUTHOR]

Purpose The aim of this study was to analyze the relationship between bone density obtained by cone-beam computed tomography ( CBCT) and morphometric parameters of bone analyzed by microcomputed tomography (μ- CT). Material and methods An overall of 32 subjects ≤8 mm of bone height were included in the study. One site per patient was randomly selected to obtain bone core. Totally, 27 biopsies were available for μ- CT analysis. In addition, CBCT was taken after positioning a previously fabricated acrylic resin template with a 2-mm-diameter metal rod at the randomly selected implant site to study radiographic bone density ( RBD). The relationship between μ- CT and CBCT quantitative variable and RBD was analyzed using Spearman correlation. Results Positive correlations between BV/ TV ( r = 0.769, P < 0.001), BS/ TV ( r = 0.563, P = 0.002), Tb. Th ( r = 0.491, P = 0.009), Tb. N ( r = 0.518, P = 0.005) and v BMD ( r = 0.699, P < 0.001) with RBD were identified. On the contrary, BS/ BV ( r = −0.509, P = 0.006), Tb. Sp ( r = −0.539, P = 0.003) and Tb. Pf ( r = −0.636, P < 0.001) were negatively correlated with RBD. Moreover, SMI ( r = −0.380, P = 0.050) and DA (−0.245, P = 0.217) were negatively correlated but not statistically significant. Conclusion This study demonstrated the correlation between radiographic bone density ( RBD) and bone density assessed by μ- CT. Therefore, our data supported the use of CBCT as pre-operative tool for implant treatment planning because it is shown to be reliable to assess atrophic posterior maxilla density and microarchitecture. [ABSTRACT FROM AUTHOR]

Objectives The objective of this study was to investigate the stability of voxel values from cone-beam CT ( CBCT) using a flat panel detector in changing surrounding circumstances mimicking clinical situations. Materials and methods Seven hydroxyapatite ( HA) rods (0, 40, 80, 120, 160, 199, and 239 mg Ca/cm3) were set in a 16 cm diameter water phantom and scanned with CBCT (FineCube) and also with multislice CT ( MSCT) used as reference. The voxel values from CBCT were measured by the obtained images with OsiriX software (http://www.osirix-viewer.com), and compared with the CT numbers from MSCT. We examined the correlation between the voxel values and the HA contents, the variance of voxel values, and the influence of changing surrounding circumstances on the voxel values. Results The voxel values from CBCT were different from the CT numbers from MSCT, but there was a linear Pearson correlation between the voxel values and the HA contents. The voxel values were greatly influenced when the samples were scanned surrounded in air. However, the voxel values were not affected significantly in the existence of materials simulating oral hard tissues and/or a metal core post. Conclusions There was a linear correlation between the voxel values of CBCT and the contents of HA rod samples. Our study indicated that it might be possible to evaluate bone mineral content (BMC) from the voxel values of CBCT for dental implant treatment. [ABSTRACT FROM AUTHOR]

The present study aims to identify radiographic methods revealing data that are most representative for the true peri-implant bone as assessed by histology. Eighty implants were placed in 10 minipigs. To assess matching between different image modalities, measurements conducted on intra-oral digital radiographs (IO), cone beam computer tomography (CBCT) and histological images were correlated using Spearman's correlation. Paired tests (Wilcoxon test) were used to determine changes in the bone parameters after 2 and 3 months of healing. Significant correlations between bone defect depth on IO and histological slices ( r=+0.7, P<0.01), as well as on CBCT images and histological slices ( r=+0.61, P<0.01), were found. CBCT and IO images deviate, respectively, 1.20 and 1.17 mm from the histology regarding bone defects. No significant correlations were detected between fractal analysis on CBCT, intra-oral radiography and histology. For bone density assessment, significant but weaker correlations ( r=+0.5, P<0.01) were found for intra-oral radiography vs. histology. Significant marginal bone-level changes could be observed after 3 months of healing using intra-oral radiography. This study allowed linking radiographic bone defect depth to the histological observations of the peri-implant bone. Minute bone changes during a short-term period can be followed up using digital intra-oral radiography. Radiographic fractal analysis did not seem to match histological fractal analysis. CBCT was not found to be reliable for bone density measures, but might hold potential with regard to the structural analysis of the trabecular bone. Corpas LS, Jacobs R, Quirynen M, Huang Y, Naert I, Duyck J. Peri-implant bone tissue assessment by comparing the outcome of intra-oral radiograph and cone beam computed tomography analyses to the histological standard Clin. Oral Impl. Res. , 2011; 492-499 doi: 10.1111/j.1600-0501.2010.02029.x [ABSTRACT FROM AUTHOR]

To study the prevalence and the degree of lingual concavity in the edentulous first molar region from cone beam computed tomography (CBCT) scans of the mandibles. Qualified cross-sectional images in mandibular first molar edentulous region taken from CBCT were selected. The mandible morphology 2 mm above the inferior alveolar canal (IAC) was classified into the convex (C), parallel (P) and undercut (U) type, based on the presence of lingual concavity and the shape of alveolar ridge. The prevalence of each group was determined. Subsequently, the lingual concavity characters, including the depth, the angulation and the vertical location were determined by the measurements of selected anatomic landmarks. One hundred and three subjects (mean age 51 with a range of 23.7-70.4 years) were studied. The U type was the most prevalent, accounting for 66% of the study population. The mean undercut depth and angulation at the level 2 mm above IAC were on average 2.4 mm and 57.7°. The mean vertical distances from the most prominent point (P) of the lingual concavity to the cemento-enamel junction of second premolar and the inferior border of the mandible were 11.7 and 14.9 mm, respectively. The anatomic location and the degree of the lingual concavity presented in this article add more information in implant treatment planning in the mandibular first molar edentulous region. Chan H-L, Brooks SL, Fu J-H, Yeh C-Y, Rudek I, Wang H-L. Cross-sectional analysis of the mandibular lingual concavity using cone beam computed tomography. Clin. Oral Impl. Res. , 2011; 201-206. doi: 10.1111/j.1600-0501.2010.02018.x [ABSTRACT FROM AUTHOR]