Jawbone measurements of edentulous sites related to implant planning using magnetic resonance imaging compared to cone beam computed tomography: An ex vivo study.

AIM: To compare measurements on images obtained by magnetic resonance imaging (MRI) and cone beam CT (CBCT) for height, width, and area in alveolar bone sites in human jaw specimens. MATERIAL AND METHODS: Forty edentulous alveolar posterior sites in human cadaver specimens were imaged using CBCT scanners, and with zero-echo-time MRI (ZTE-MRI). Semi-automatic volume registration was performed to generate representative coronal sections of the sites related to implant planning. ZTE-MRI sections were also presented after grayscale inversion (INV MRI). Three observers measured bone height, bone width 5 mm from the alveolar crest, and bone area stretching from the width measurement to the top of the alveolar crest in the images. Interobserver agreement was assessed by intra-class correlation coefficients (ICC). The measurements were analyzed using two-way repeated measures ANOVA factoring observer and image type. RESULTS: ICC was >0.95 for bone height, width, and bone area. No significant differences among observers (p = 0.14) or image type (p = 0.60) were found for bone height. For bone width, observer (p = 0.14) was not a significant factor, while ZTE-MRI produced width estimates that were significantly different and systematically smaller than CBCT-based estimates (p ≤ 0.001). Observer (p = 0.06) was not a significant factor regarding the bone area measurements, contrary to the imaging type where ZTE-MRI led to significantly smaller area estimates than CBCT (p ≤ 0.001). CONCLUSION: Bone height measurements were essentially equivalent using CBCT and MRI. This was found regardless of grayscale choice for the MRI. However, ZTE-MRI resulted in smaller estimates of bone width and area.

Long-term prognosis for teeth with external cervical resorption based on periapical images and cone beam CT: A clinical study.

AIM: To evaluate whether supplemental information from CBCT changed long-term prognosis for teeth with external cervical resorption (ECR) compared to periapical (PA) images. Furthermore, to assess predictive findings in PA images and evaluate which findings in CBCT affected the long-term prognosis of teeth with ECR. METHODOLOGY: One hundred and ninty-four patients, mean age 41.2, range 13-81, having 244 teeth with ECR were included. An initial long-term prognosis determined either good or poor was established based on intraoral images. Afterwards, the patients underwent CBCT, and final long-term prognosis was decided. From the PA images and CBCT, ECR using Heithersay's classification system, pulp involvement and extension of ECR was assessed. In CBCT, the number of surface lesion(s) was additionally assessed. Descriptive statistics evaluated changes in long-term prognosis after CBCT. Logistic regression analyses tested if findings in PA images and CBCT affected the long-term prognosis. RESULTS: Based on CBCT, out of 244 teeth the long-term prognosis was assessed to be poor for 173 (70.9%) teeth and good for 71 (29.1%) teeth. The long-term prognosis changed in 76 (31.1%) teeth after CBCT; 5 (2.0%) changed from poor to good, and 71 (29%) changed from good to poor long-term prognosis. In 81 (33.2%) teeth the H-class increased, and in 10 (4.1%) teeth the H-class decreased after assessing CBCT. In 70 (28.7%) teeth, there was a change from no pulp involvement to involvement of the pulp after CBCT; eight (3.3%) teeth changed in the opposite direction. H-class 2 and 4 in PA images significantly increased the probability for a change in long-term prognosis compared to an H-class 3 (p < .05). H-class 4, pulp involvement, ECR in the oral 1/3 of the root, and more than two surface lesions seen in CBCT significantly influenced a poor long-term prognosis (p < .05). CONCLUSIONS: Supplemental information from CBCT changed long-term prognosis in almost one third of teeth with ECR. In most cases, the long-term prognosis changed from good to poor. H-class 3 in PA images had a significant influence on change in long-term prognosis. Several findings in CBCT influenced a poor long-term prognosis.

Will supplemental cone beam computed tomography change the treatment plan of impacted maxillary canines based on 2D radiography? A prospective clinical study.

AIM: To evaluate the impact of cone beam computed tomography (CBCT) on treatment planning for impacted maxillary canines; secondly, to identify CBCT factors influencing a change in the treatment plan; and thirdly, to assess 2D radiographic factors that can aid in selecting appropriate candidates for CBCT. MATERIAL AND METHODS: Patients with impacted maxillary canines and an overlap of a neighboring tooth in 2D radiographs and the suspicion of root resorption were referred for CBCT examination. An initial treatment plan was based on 2D radiographs, and the final treatment plan was established after the CBCT examination. Logistic regression analyses and t-tests were performed to evaluate differences in radiographic findings between the groups with and without a change in treatment plan. RESULTS: The study prospectively included 125 impacted canines, and 43 (34.4%) of them had a change in treatment plan after the CBCT examination. The most common change was a modification in the direction of cantilever traction (n = 28; 22.4%), while the least common was the change in decision to remove/keep the canine (n = 4; 3.2%). The size of the alpha and lateral angles had a significant impact on the decision to change the treatment plan. Other radiographic findings did not influence a change in treatment plan. CONCLUSIONS: One-third of the canines had a change in treatment plan after supplemental CBCT examination. Canines with large alpha and lateral angles measured in the panoramic image were found to be significantly more likely to undergo changes in the initial direction of cantilever traction or changes to the canine extraction strategy following CBCT examination.

Alveolar bone measurements in magnetic resonance imaging compared with cone beam computed tomography: a pilot, ex-vivo study.

OBJECTIVES: To compare alveolar bone height and width measurements from zero-echo-time MRI (ZTE-MRI) and cone beam CT (CBCT), in human specimens. MATERIAL AND METHODS: Twenty posterior edentulous sites in human cadaver specimens were imaged with CBCT and ZTE-MRI. Bone height and width at 1, 3, 5, 7 and 9 mm from the top of the alveolar ridge was measured by two trained observers in cross-sections of a site where an implant was to be planned. Twenty percent of the sample was measured in duplicate to assess method error and intra-observer reproducibility (ICC). The differences between CBCT and ZTE-MRI measurements were compared (t-test). RESULTS: Inter- and intra-observer reproducibility was >0.90. The method error (average between observers) for bone height was 0.45 mm and 0.39 mm, and for bone width (average) was 0.52 mm and 0.80 mm (CBCT and ZTE-MRI, respectively). The majority of the bone measurement differences were statistically insignificant, except bone width measurements at 5 mm (p ≤ .05 for both observers). Mean measurement differences were not larger than the method error. CONCLUSION: ZTE-MRI is not significantly different from CBCT when comparing measurements of alveolar bone height and width.

Reliability of radiographic findings in large FOV CBCTs of mandibular third molars as basis for pre-operative patient information.

OBJECTIVE: The aim of this study was to assess the relation between radiographic findings in large field of view (FOV) cone beam computed tomography (CBCT) exams and clinical findings of mandibular third molars in relation to the pre-operative patient information. MATERIAL AND METHODS: Two hundred and nine mandibular third molars in 134 orthognathic patients examined with CBCT were removed. Three observers assessed tooth- and mandibular canal-related variables in CBCT images, and the findings were correlated to clinical findings during surgery for all observers: tooth angulation, number and morphology of roots and close relationship between the tooth and the mandibular canal. Moreover, positive (PPV) and negative (NPV) predictive values and positive (LR+) and negative (LR-) likelihood ratios were calculated for the canal-related variables. Inter- and intra-observer reproducibility was expressed as percentage accordance and kappa-statistics. RESULTS: Generally, there was high correlation between radiographic and clinical tooth-related variables. The opposite was true for the canal-related variables, since the PPV and LR + were low. The highest PPV and LR + were found when the mandibular canal was positioned between the roots of the third molar. CONCLUSIONS: Tooth-related findings in CBCT are reliable, whereas mandibular canal-related findings should not affect the information provided to the patient pre-operatively.

Effect of a formalin-based fixation method on bone mineral content in human ex-vivo specimens.

OBJECTIVE: Histopathology of formalin-fixated human ex-vivo specimens may be used as reference standard for evaluation of diagnostic index tests like CBCT or MRI. The aim was to estimate changes in bone mineral content (BMC) over time in human ex-vivo bone specimens fixated in a formalin-based solution for 24 h followed by storage in an alcohol-based medium for six months, assessed by dual-energy X-ray absorptiometry (DXA). METHODOLOGY: Bone specimens (n = 19) from human ex-vivo mandibles donated for science were included. BMC was measured by DXA before fixation (D0), after 24 h of immersion fixation in a formalin-based solution (D1), and hereafter every 30 days (M1-M6) during storage in a 30% ethanol-based storage medium for 6 months. Changes in BMC from D0 to D1 and from D0 to M6 were calculated and mean change in BMC estimated. RESULTS: Mean change in BMC from D0 to D1 was -0.73% (95% CI -1.75%; 0.29%), and from D0 to M6 -1.19% (95% CI -2.14%; -0.23%). CONCLUSIONS: No changes in BMC of ex-vivo human bone specimens were found after 24 h formalin-based immersion fixation. After six months storage in an ethanol-based medium, BMC mean loss of 1% was detected. In this range, changes in BMC are not clinically relevant.

Sella Turcica Area and Location of Point Sella in Cephalograms Acquired with Simulated Patient Head Movements.

AIM AND OBJECTIVE: This study assesses changes in the sella turcica area (STA) and location of the cephalometric point sella (S) on lateral cephalograms acquired by charge-coupled device (CCD)-based cephalostats with and without simulated patient head movements. MATERIALS AND METHODS: A real skull was placed on a robot, able to simulate four head movements (anteroposterior translation/lifting/nodding/lateral rotation) at three distances (0.75/1.5/3 mm) and two patterns (returning to 0.5 mm away from the start position/staying at maximum movement excursion). Two ProMax-2D cephalostats (Dimax-3, D-3 or Dimax-4, D-4), and an Orthophos-SL cephalostat (ORT) acquired cephalograms during the predetermined movements ("cases," 48 images/unit) and without movement ("controls," 24 images/unit). Three observers manually traced the contour of sella turcica and marked point sella using a computer mouse. STA was calculated in pixels2 by dedicated software based on the tracing. S was defined by its x and y coordinates recorded by the same software in pixels. Ten percent of the images were assessed twice. The difference between cases and controls (case minus control) for the STA and S (namely Diff-STA and Diff-S) was calculated and assessed through descriptive statistics. RESULTS: Inter- and intraobserver agreement ranged from moderate to good for STA and S. Diff-STA ranged from -42.5 to 12.9% (D-3), -15.3 to 9.6% (D-4), and -25.3 to 39.9% (ORT). Diff-S was represented up to 50% (D-3), 134% (D-4), and 103% (ORT) of the mean sella turcica diameter in control images. CONCLUSION: Simulated head movements caused significant distortion in lateral cephalograms acquired by CCD-based cephalostats, as seen from STA and S alterations, depending on the cephalostat. CLINICAL SIGNIFICANCE: Patient-related errors, including patient motion artifacts, are influential factors for the reliability of cephalometric tracing.

Influence of residual bone height and sinus width on the outcome of maxillary sinus bone augmentation using anorganic bovine bone.

OBJECTIVE: To evaluate the influence of the posterior residual bone height and sinus width on the outcome of maxillary sinus bone augmentation using anorganic bovine bone. MATERIAL AND METHODS: Bilateral sinus bone augmentation was performed using anorganic bovine bone in 20 patients with residual bone height <2 mm in at least one site on each side. Trephine samples were removed at the implant insertion site 8 months after the grafting procedure, and histological and histomorphometric analyses were performed to examine the relative amount (%) of new bone, anorganic bovine bone, and soft tissue in the grafted area. Based on cone beam computed tomography evaluation, the sites of implant insertion were classified according to sinus width into narrow, average, and wide, and according to residual bone height into ≤2 and >2 mm. RESULTS: A total of 146 implants were installed and 103 biopsies were evaluated. New bone formation in sites classified as narrow (69 sites), average (19 sites), and wide (15 sites) was 28.5% ± 9.24, 28.9% ± 8.61, and 30.3% ± 7.80, respectively. The mean posterior maxillary residual bone height was 4.0 ± 2.43 mm, and 26 and 77 sites were classified as ≤2 and >2 mm, respectively. New bone formation was 26.2% ± 9.10 and 29.8% ± 8.67 for residual bone height ≤2 and >2 mm, respectively. The differences were non-significant. CONCLUSIONS: Within the limitations of the present study, posterior residual bone height and sinus width were not factors with influence on new bone formation in sinuses grafted exclusively with anorganic bovine bone after 8 months of healing.

Marginal bone level in two Danish cross-sectional population samples in 1997-1998 and 2007-2008.

OBJECTIVE: The aim of this study was to compare the marginal bone level of two randomly selected population samples from 1997/1998 and 2007/2008, with special emphasis on the role of smoking habits and gender. MATERIALS AND METHODS: Two cross-sectional randomly selected population samples [1997/1998 (N = 616) and 2007/2008 (N = 396)] were analysed with respect to the marginal bone level. The marginal bone level was measured in full-mouth intraoral radiographs. Information on smoking was gathered using questionnaires. Multiple regression analysis was used in order to adjust for correlating factors (gender, age, smoking habits and number of teeth). RESULTS: After adjusting for confounding factors, the population sample from 2007/2008 had on average a slightly, but statistically significantly, more reduced average marginal bone level (0.15 mm) than the population sample from 1997/1998. Men had more reduced marginal bone level than women (0.12 mm). Smokers in both population samples had more reduced marginal bone level than non-smokers (0.39 mm and 0.12 mm for 1997/1998; 0.65 mm and 0.16 mm for 2007/2008). CONCLUSIONS: In these populations, sampled 10 years apart, the 2007/2008 population sample had a slightly more reduced marginal bone level than the 1997/1998 population sample. Men had more reduced marginal bone level than women, and smoking is considered a major risk factor for a reduced marginal bone level.

Factors affecting the possibility to detect buccal bone condition around dental implants using cone beam computed tomography.

OBJECTIVES: To evaluate factors with impact on the conspicuity (possibility to detect) of the buccal bone condition around dental implants in cone beam computed tomography (CBCT) imaging. MATERIAL AND METHODS: Titanium (Ti) or zirconia (Zr) implants and abutments were inserted into 40 bone blocks in a way to obtain variable buccal bone thicknesses. Three combinations regarding the implant-abutment metal (TiTi, TiZr, or ZrZr) and the number of implants (one, two, or three) were assessed. Two CBCT units (Scanora 3D - Sc and Cranex 3D - Cr) and two voxel resolutions (0.2 and 0.13 mm) were used. Reconstructed sagittal images (2.0 and 5.0 mm thickness) were evaluated by three examiners, using a dichotomous scale when assessing the condition of the buccal bone around the implants. A multivariate logistic regression was performed using examiners' detection of the buccal bone condition as the dependent variable. Odds ratio (OR) were calculated separately for each CBCT unit. RESULTS: Implant-abutment combination (ZrZr) (OR Sc = 19.18, OR Cr = 11.89) and number of implants (3) (OR Sc = 12.10, OR Cr = 4.25) had major impact on buccal bone conspicuity. The thinner the buccal bone, the higher the risk that the condition of the buccal bone could not be detected. The use of lower resolution protocols increased the risk that buccal bone was not properly detected (OR Sc = 1.46, OR Cr = 2.00). For both CBCT units, increasing the image reconstruction thickness increased the conspicuity of buccal bone (OR Sc = 0.33, OR Cr = 0.31). CONCLUSIONS: Buccal bone conspicuity was impaired by a number of factors, the implant-abutment material being the most relevant. Acquisition and reconstruction factors had minor impact on the detection of the buccal bone condition.

Marginal Bone Loss after Ten Years in an Adult Danish Population: A Radiographic Study.

PURPOSE: To evaluate marginal bone loss over a 10-year period in individuals and in tooth groups in relation to age and level of marginal bone. MATERIALS AND METHODS: In 1997, 616 randomly selected individuals (mean age: 42 years, range: 21-63 years) underwent a full-mouth radiographic survey. In 2008, the survey was repeated in 362 of the same individuals (182 women and 180 men). The marginal bone level of each tooth was measured in mm from the cementoenamel junction to the marginal bone. These measurements were used to calculate marginal bone loss during the 10-year period for individuals and tooth groups in relation to age and to baseline marginal bone level, calculated as the average between measurements in 1997 and 2008 to circumvent regression towards the mean. RESULTS: The average annual marginal bone loss was 0.09 mm (SD ±â€¯0.04 mm) during the 10-year study period. The association between marginal bone loss and baseline marginal bone level was more pronounced in the youngest age group, compared to the other age groups. Molars displayed the most severe bone loss during the study period. CONCLUSION: Marginal bone loss over a 10-year period is associated with age and baseline marginal bone level. Younger individuals with a reduced marginal bone level were at higher risk for further bone loss. Molars lose marginal bone more rapidly than other tooth groups.

Fate of the buccal bone at implants placed early, delayed, or late after tooth extraction analyzed by cone beam CT: 10-year results from a randomized, controlled, clinical study.

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.

Remodeling of cortical and corticocancellous fresh-frozen allogeneic block bone grafts--a radiographic and histomorphometric comparison to autologous bone grafts.

OBJECTIVES: To compare cortical (AL-C) and corticocancellous (AL-CC) fresh-frozen block bone allografts to cortical block bone autografts (AT) used for lateral ridge augmentation in terms of radiographic dimensional maintenance and histomorphometrical graft remodeling. MATERIALS AND METHODS: Twenty-four patients, requiring ridge augmentation in the anterior maxilla prior to implant placement, were treated with AT, AL-C or AL-CC bone blocks (eight patients per graft type). Patients were examined with CBCT prior to, 14 days, and 6-8 months after grafting. Amount of augmentation and dimensional block graft maintenance over time was evaluated by comparing planimetric measurements of the alveolar ridge made on CBCT sections of the augmentation area. During implant installation surgery, 6-8 months after grafting, cylindrical biopsies were harvested perpendicularly to the lateral aspect of the augmented alveolar ridge. The relative volumes of vital and necrotic bone and soft tissues were histomorphometrically estimated. Comparisons among groups and observation times were performed using Friedman test followed by Dunn's post-hoc test. RESULTS: Radiographic evaluation showed that the three types of grafts resulted in a significant increase in alveolar ridge width, with no significant differences among the groups in terms of ridge dimensions at the various observation times. However, significant graft resorption (P = 0.03) was observed in the AL-CC group over time (-8.3 ± 7.1%) compared with the AT and AL-C groups, where a slight increase was observed, on average (1.5 ± 20.6% and 1.3 ± 14.9%, respectively). Histomorphometrical analysis showed that larger amounts of vital bone were found in the biopsies from the AT augmented sites (25.1 ± 11.2%) compared with AL-CC and AL-C augmented sites (9.3 ± 3.8% and 3.9 ± 4.6%, respectively; P ≤ 0.01). AL-CC and AT biopsies had the smallest amount of necrotic bone (38.2 ± 12.1% and 56.7 ± 26.0, respectively) compared with AL-C (83.7 ± 10.8%, P < 0.01) biopsies. AL-CC biopsies showed the largest amount of soft tissues (52.5 ± 11.7%) compared with those from AT (18.1 ± 17.1%, P = 0.03) and AL-C (12.3 ± 8.5%, P < 0.01) sites. CONCLUSIONS: AL block bone graft architecture influences significantly its dimensional incorporation and remodeling. Compared with AT bone graft, a small portion of the AL block consists of vital bone 6-8 months after grafting. Cortical AL blocks seem to show the least amounts of vital bone, while corticocancellous AL blocks seem to undergo more resorption over time.

Diagnostic accuracy of conventional and digital radiography for detecting misfit between the tooth and restoration in metal-restored teeth.

STATEMENT OF PROBLEM: Although the postprocessing of digital images with enhancement filters could lead to the presence of artifacts and result in false-positive diagnoses, no study has analyzed whether the use of digital radiographs and/or postprocessing of digital images interferes with the diagnosis of marginal adaptation in metal-restored teeth. PURPOSE: The purpose of this study was to compare the diagnostic accuracy of conventional and digital radiographic images with and without filters for detecting a misfit between the tooth and restoration in metal-restored teeth. MATERIAL AND METHODS: Forty teeth with mesial-occlusal-distal inlays and 40 with complete crowns (each with a perfect fit, 20 with a 0.2-mm gap and 20 with a 0.4-mm gap) were imaged with conventional film and digital phosphor plate systems. Digital radiographs were exported as original images and with edge enhancement (high and low), inversion, and pseudo-3-dimensional filters. Four examiners assessed the presence of gaps by using a categorical scale (fit, misfit, cannot decide). Sensitivity, specificity, and overall accuracy were calculated for each variable. In addition, time spent scoring the images was recorded. A multivariate logistic regression was performed with accuracy as the dependent variable. RESULTS: Of the images, 6.2% received the score "cannot decide," most of them with a high edge enhancement filter and in the crown group. A tendency for higher sensitivity (range 0.67-0.83), specificity (range 0.81-0.92), and accuracy (range 0.73-0.86) values was found in conventional and digital original images. Results of a logistic regression found that restoration type, gap size, and high enhancement and inversion filters had a statistically significant impact on accuracy (P<.05). CONCLUSIONS: Original nonfiltered images should be used to assess teeth with metal restorations. High enhancement filters and image inversion should be avoided, especially when metal crowns are present.

Early, delayed, or late single implant placement: 10-year results from a randomized controlled clinical trial.

AIM: The aim of this study was to present the 10-year clinical and radiographic data from a RCT on single-tooth implants placed early, delayed, or late after tooth extraction. MATERIALS AND METHODS: Sixty-three patients were randomly allocated to three groups and received an implant on average 10 days (Ea), 3 months (De), or 17 months (La) after tooth extraction. Second-stage surgery was performed after 3 months of submerged healing; metal-ceramic crowns were cemented after one additional month. Standardized periapical radiographs were taken 1 week after implant placement (TP), 1 week (TC) and 1-1.5 year (T1) after crown delivery, and 10 years after implant placement (T10). Pocket depth (PD) and bleeding on probing were registered during controls (TC - T10). RESULTS: Two Ea and one De implants failed to osseointegrate. Seven patients (4 Ea, 1 De, and 2 La) were not available at T10 . No significant differences were found among groups regarding implant survival or radiographic peri-implant marginal bone levels (Ea: 1.15 ± 0.77; De: 1.53 ± 1.06; La: 1.42 ± 1.07) at T10 . Similarly, no differences were observed among groups in the number of implants with PD ≥ 5 mm (Ea: 29%; De: 35%; La: 44%) or the average depth of the sites with PD ≥ 5 mm (Ea: 5.4 ± 0.7; De: 6.1 ± 1.4; La: 5.4 ± 0.5) at T10 . Peri-implant mucositis was found in 70% of the cases; peri-implantitis was diagnosed only in two implants (1 De, 1 La) corresponding to 4.3%. CONCLUSION: Single-tooth implants placed early or delayed after tooth extraction show high survival rates and limited peri-implant marginal bone resorption or biological complications, similar to what is observed with implants placed according to the conventional (late) protocol.

Planning of dental implant size with digital panoramic radiographs, CBCT-generated panoramic images, and CBCT cross-sectional images.

OBJECTIVES: To compare the implant size (width and length) planned with digital panoramic radiographs, cone beam computed tomography (CBCT)-generated panoramic views, or CBCT cross-sectional images, in four implant systems. MATERIAL AND METHODS: Seventy-one patients with a total of 103 implant sites in the upper premolar and/or lower molar regions were examined with digital panoramic radiography (D-PAN) and (CBCT). A metal ball 5 mm in diameter was placed in the edentulous area for the D-PAN. CBCT data sets were reformatted to a 10-mm thick CBCT panoramic view (CBCT-pan) and 1-mm cross-sections (CBCT-cross). Measurements were performed in the images using dedicated software. All images were displayed on a monitor and assessed by three observers who outlined a dental implant by placing four reference points in the site of the implant-to-be. Differences in width and length of the implant-to-be from the three modalities were analyzed. The implant size selected in the CBCT-cross images was then compared to that selected in the other two modalities (D-PAN and CBCT-pan) for each of the implant systems separately. RESULTS: The implant-to-be (average measurements among observers) was narrower when measured in CBCT-cross compared with both D-PAN and CBCT-Pan. For premolar sites, the width also differed significantly between D-PAN and CBCT-pan modalities. The implant-to-be was also significantly shorter when recorded in CBCT-cross than in D-PAN. In premolar sites, there were no significant differences in implant length among the three image modalities. It mattered very little for the change in implant step sizes whether CBCT-cross was compared to D-PAN or CBCT-pan images. CONCLUSION: Our results show that the selected implant size differs when planned on panoramic or cross-section CBCT images. In most cases, implant size measured in cross-section images was narrower and shorter than implant size measured in a panoramic image or CBCT-based panoramic view.

Is thermography useful for assessment of postoperative inflammation after surgical removal of mandibular third molars when methylprednisolone is administered and how does it correlate with patients' perception of swelling?

PURPOSE: To assess the differences in facial skin temperature after mandibular third molar removal when patients received methylprednisolone and placebo, respectively and to assess the correlation between patient-reported swelling using a visual analog scale (VAS) and facial skin temperature measured using thermography. PATIENTS AND METHODS: The study involved patients with 2 mandibular third molars with an indication for removal. The patients received either methylprednisolone or placebo in a randomized, crossover study design. Thermograms and the swelling VAS score were recorded 2 days after surgery. The outcome variable was the temperature difference (Δt) between the operated and control sides. A 2-sample t test analyzed the difference in Δt between the first and second operations. Spearman's rank correlation analysis was used to assess the correlation between the swelling VAS scores and the Δt. RESULTS: A total of 124 patients (67 males, 57 females, mean age 25 years) had both mandibular third molars removed on 2 separate occasions. No difference in Δt was found when methylprednisolone and placebo were given (P = .07). In addition, the correlation between the swelling VAS score and Δt was 0.30 (P = .001) and 0.09 (P = .3) after the first and second operation, respectively. CONCLUSIONS: Thermography does not seem sensitive enough to detect differences in the inflammatory response when patients received methylprednisolone or placebo. The correlation between the Δt and patient-reported swelling was low (≤0.3).

Radiographic display of carious lesions and cavitation in approximal surfaces: Advantages and drawbacks of conventional and advanced modalities.

BACKGROUND: Treatment strategies have changed with efforts on arresting carious lesions suspected to have an intact surface sparing operative treatment for cavitated lesions. Radiography is still the most recommended adjunct method in the diagnosis of clinically inaccessible approximal surfaces. BITEWING RADIOGRAPHY: The major drawback of bitewing radiography for caries diagnosis is that the clinical state of the surface cannot be determined; i.e. if cavitation has developed or the demineralized surface is still intact. Based on studies of the relationship between radiographic lesion depth and clinical cavitation in approximal surfaces, a threshold for operative treatment decision has been suggested when a lesion is observed radiographically more than one-third into dentine. However, the results from previous studies are contradictory and the majority of studies are ~25 years old. In addition, there are few longitudinal observational studies on the behaviour of dentinal carious lesions, particularly in adults. CONE BEAM COMPUTED TOMOGRAPHY: Cone beam CT is an advanced 3-dimensional radiographic modality, which seems much more accurate than intra-oral modalities for displaying cavitation in approximal surfaces. Nonetheless, there are several drawbacks with CBCT, such as radiation dose, costs and imaging artefacts. Therefore, CBCT cannot be advocated at current as a primary radiographic examination with the aim of diagnosing cavitated carious lesions. CONCLUSIONS: Bitewing radiography is, thus, still state-of-the-art as an adjunct in diagnosing carious lesions in clinically inaccessible approximal surfaces. The risk for cavitation is related to lesion depth, but new studies are needed in both child and adult populations to validate current thresholds for the operative treatment decision based on the radiographic lesion depth.

Clinical cavitation and radiographic lesion depth in proximal surfaces in an Indian population.

OBJECTIVES: To assess the relationship between clinical cavitation and radiographic caries lesion depth in proximal surfaces of permanent posterior teeth in an Indian population. This study also assessed the clinical feasibility of applying 'western guidelines' to this population from the developing world. MATERIALS AND METHODS: Relationship between clinical cavitation and radiographic caries lesion depth in proximal surfaces in an Indian population was assessed. Proximal surfaces (n = 126) without restorations were examined on bitewing radiographs in patients with suspected caries and lesion depth was recorded by five observers. The radiographic scoring scale was 0 = sound; 1 = lesion in enamel; 2 = lesion in outer 1/3 of dentine and 3 = lesion in inner 2/3 of dentine. Orthodontic separators were placed interdentally and removed after 3 days, where surfaces were recorded as cavitated (yes/no) by two clinical validators (gold standard). RESULTS: Enamel lesions were cavitated in 25.6-38.3%, outer dentinal lesions were cavitated in 83.3-100% and inner dentinal lesions were cavitated in 96.4-100% depending on observer and validator. On applying 'western guidelines' for treatment decision to the radiographic findings of lesion depth, 80-100% of the lesions observed in outer dentine would lead to a false (non-operative) treatment decision. CONCLUSIONS: Radiographic shallow carious lesions were often cavitated in this population. The threshold for cavitation in this study population is suggested to be set between enamel and outer dentine in contrast to western guidelines.

Treatment plan for maxillary third molars based on radiological findings varies among oral surgeons - a web-based "paper" clinic study.

OBJECTIVES: To evaluate variation in treatment plans and pathological findings related to maxillary second and third molars based on panoramic (PAN) images and cone beam CT (CBCT) among Danish and Dutch oral and maxillofacial surgeons. STUDY DESIGN: This web-based "paper" clinic contained 10 cases of impacted maxillary third molars comprising clinical information, PAN, and CBCT. Treatment plan and pathological findings were established based on clinical information and PAN, thereafter, based on CBCT by 28 surgeons. Options for treatment plan for third molars were no treatment, or tooth removal. Options for treatment plan for second molars were no treatment, tooth removal, or endodontic and/or filling therapy. The surgeons assessed external root resorption, marginal bone loss, and follicular space. RESULTS: A change in treatment plan between PAN and CBCT was registered between 0% and 43% of the surgeons among the cases. The surgeons did not agree completely on the treatment plan in any of the cases. Variation was present among the surgeons evaluating pathological findings. In several cases, severity of root resorption was rated worse in CBCT than in PAN. CONCLUSIONS: Variation in treatment plan and pathological findings was observed among surgeons. No correlation between change in pathological findings and change in treatment plan was found.