Assessment of peri-implant defects at titanium and zirconium dioxide implants by means of periapical radiographs and cone beam computed tomography: An in-vitro examination

Influence of the Tube Angle on the Measurement Accuracy of Peri-Implant Bone Defects in Rectangular Intraoral X-ray Imaging

BACKGROUND

Intraoral radiography in the right-angle technique is the standard procedure to examine the peri-implant bone level in implant follow-up and implant-related studies. For the implementation of the right-angle or parallel technique, mostly ready-made image receptor holders are used. The aim of this experimental study is to analyze changes in the measurement of standardized peri-implant defects caused by a deviation in the position of the image receptor.

METHODS

Eleven Xive® implants (Dentsply Sirona, Bensheim, Germany) were placed in bovine bone, and peri-implant defects of varying depths were created. The preparations were fixed in a specially made test stand, and intraoral radiographs were taken using the right-angle technique with standard film holders at various horizontal and vertical projection angles. Defect measurement was carried out with the imaging software Sidexis 4 V 4.3 (Dentsply Sirona, Bensheim, Germany).

RESULTS

With increasing angular deviation, larger deviations between the measured and the real extent of the defect occurred. Vertical tilting caused significant distortion, while horizontal rotation showed less effect.

CONCLUSION

Intraoral radiography only provides a valid representation of the peri-implant bone level for follow-up or as a tool in implant-related studies if a reproducible projection direction is assured.

Retrospective Analysis of Artifacts in Cone Beam Computed Tomography Images Used to Diagnose Chronic Rhinosinusitis

BACKGROUND

Cone beam computed tomography (CBCT) is frequently used to corroborate the signs and symptoms of chronic rhinosinusitis (CRS). However, artifacts induced by dental restorations might complicate the diagnosis of CRS. Here, we assessed the frequency and location of artifacts in CBCT images taken to confirm the CRS.

METHODS

All CBCT images of the patients referred to the Emergency Radiology unit, Turku University Hospital, with an indication of CRS in 2017 were re-examined. The prevalence of the artifacts was analyzed in three cross-sectional views and three horizontal levels delimited by anatomical landmarks.

RESULTS

In total, 214 CBCT images of patients with CRS were evaluated. The diagnosis of apical periodontitis (AP) was impaired by artifacts present in 150/214 images (70%). The diagnosis of CRS was impaired in 5 of the 214 images (2.3%). The main origins of the artifacts were large dental fillings or crowns, and endodontic fillings were present in 95% (203/214) and 52% (111/214) of the images, respectively.

CONCLUSIONS

AP as an etiology of CRS is possible to miss because of artifacts originating from dental and endodontic fillings in the CBCT images of the paranasal sinuses.

Analysis of peri-implant bone defects by using cone beam computed tomography (CBCT): an integrative review

The objective of this work was to perform an integrative review of the inspection of peri-implant bone defects using cone beam computed tomography (CBCT). An electronic search was performed in the PubMed database using the following scientific terms: CBCT or Cone Beam computed tomography; dental implant; peri-implant; bone loss; defects. The survey identified 267 studies, of which 18 were considered relevant to this study. These studies provided important data taking into account the accuracy of cone beam computed tomography in the detection and measurement of peri-implant bone defects such as fenestrations, dehiscence and intraosseous circumferential defects. The effectiveness of CBCT in aiding in geometric bone calculations and in the diagnosis of peri-implant defects was influenced by factors such as artefacts, defect size, bone wall thickness, implant material, adjustment of acquisition parameters and observer experience. A not insignificant number of studies compared intraoral radiography to CBCT in the detection of peri-implant bone loss. CBCT was clearly superior to intraoral radiography in the detection of all peri-implant bone defects, except for defects located in the interproximal zone. In general, studies have shown that peri-implant bone measurements adjacent to the implant surface can be correctly determined, as well as the diagnosis of peri-implant bone defects with an average discrepancy of less than 1 mm from the actual measurement of the defect.

Reliability and accuracy of intraoral radiography, cone beam CT, and dental MRI for evaluation of peri-implant bone lesions at zirconia implants - an ex vivo feasibility study

OBJECTIVES

To determine the reliability and accuracy of intraoral radiography (IR), cone-beam-computed tomography (CBCT), and dental magnetic resonance imaging (dMRI) in measuring peri‑implant bone defects around single zirconia implants.

METHODS

Twenty-four zirconia implants were inserted in bovine ribs with various peri‑implant defect sizes and morphologies. True defect extent was measured without implant in CBCT. Defects were measured twice in IR, CBCT, and dMRI with the inserted implant by three experienced readers. Reliability was assessed by ICC, accuracy by the Friedman test, and post-hoc-Tukey's test.

RESULTS

A comparable good to excellent intra- and inter-reader reliability was observed for all modalities (intra-/inter-rater-CC range for IR; CBCT; dMRI: 0.81-0.91/0.79;0.87-0.97/0.96;0.87-0.95/0.94). Accuracy was generally high, with mean errors below 1 mm in all directions. However, measuring defect depth in the mesiodistal direction was significantly more accurate in dMRI (0.65 ± 0.38 mm) compared to IR (2.71 ± 1.91 mm), and CBCT (1.98 ± 1.97 mm), p-values ≤ 0.0001 respectively ≤ 0.01.

CONCLUSIONS

Osseous defects around zirconia implants can be reliably measured in IR/CBCT/dMRI in the mesiodistal directions. In addition, CBCT and dMRI allow assessment of the buccolingual directions. dMRI provides a comparable accuracy in all directions, except for the mesiodistal defect depth, where it outperforms IR and CBCT.

Diagnostic accuracy of imaging examinations for peri-implant bone defects around titanium and zirconium dioxide implants: A systematic review and meta-analysis

Purpose

This systematic review and meta-analysis assessed the diagnostic accuracy of imaging examinations for the detection of peri-implant bone defects and compared the diagnostic accuracy between titanium (Ti) and zirconium dioxide (ZrO₂) implants.

Materials and Methods

Six online databases were searched, and studies were selected based on eligibility criteria. The studies included in the systematic review underwent bias and applicability assessment using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool and a random-effect meta-analysis. Summary receiver operating characteristic (sROC) curves were constructed to compare the effect of methodological differences in relation to the variables of each group.

Results

The search strategy yielded 719 articles. Titles and abstracts were read and 61 studies were selected for full-text reading. Among them, 24 studies were included in this systematic review. Most included studies had a low risk of bias (QUADAS-2). Cone-beam computed tomography (CBCT) presented sufficient data for quantitative analysis in ZrO₂ and Ti implants. The meta-analysis revealed high levels of inconsistency in the latter group. Regarding sROC curves, the area under the curve (AUC) was larger for the overall Ti group (AUC=0.79) than for the overall ZrO₂ group (AUC=0.69), but without a statistically significant difference between them. In Ti implants, the AUCs for dehiscence defects (0.73) and fenestration defects (0.87) showed a statistically significant difference.

Conclusion

The diagnostic accuracy of CBCT imaging in the assessment of peri-implant bone defects was similar between Ti and ZrO₂ implants, and fenestration was more accurately diagnosed than dehiscence in Ti implants.

Measuring peri-implant bone lesions using low-dose cone-beam computed tomography

PURPOSE

High-definition cone-beam computed tomography (HD-CBCT) offers superior image quality at the cost of higher radiation dose compared to low-dose CBCT (LD-CBCT). The aim of this study was to investigate whether peri-implant bone lesions can be accurately quantified using LD-CBCT, even when including the influence of surrounding tissues.

METHODS

Twelve titanium implants restored with all-ceramic crowns were placed in bovine bone, and peri-implant lesions were prepared. Radiographic imaging was performed using IR (intraoral radiography), HD-CBCT and LD-CBCT. To simulate the in-vivo situation, the samples were placed inside a dry human mandible, and a second LD-CBCT imaging was performed (LD-CBCT*). The datasets were presented to four observers in random order. Maximum lesion depth and width were measured in a standardized mesiodistal slice in IR, HD-CBCT, LD-CBCT, and LD-CBCT*. Mean lesion depth and width measurements for each sample in HD-CBCT served as reference.

RESULTS

Interrater agreement was slight for depth and excellent for width in HD-CBCT and both LD modes. For all observers, measurement deviations from HD-CBCT were below 0.3 mm in the LD protocols (LD-CBCT depth: 0.22 ± 0.17 mm, width: 0.22 ± 0.13 mm; LD-CBCT* depth: 0.24 ± 0.23 mm, width: 0.25 ± 0.21 mm) and at 0.4 mm in IR.

CONCLUSIONS

Absolute differences between LD-CBCT and HD-CBCT are small, although surrounding tissues decrease LD-CBCT image quality. Within the limitations of an in-vitro trial, LD-CBCT may become an adequate imaging modality for monitoring peri-implant lesions at a substantially decreased radiation dose.

Internal hexagon versus conical implant-abutment connections: evaluation of 3-year postloading outcomes

Different types of internal implant-abutment connections, namely hexagon and conical, have been used for implant restoration. However, data regarding the benefits of these internal connections in terms of clinical outcomes are scarce. Accordingly, the aim of this study was to compare radiographic marginal bone loss (RMBL) and associated implant complications between implants with internal hexagon (IH) connections and those with internal conical (IC) connections. Forty-nine patients with 98 implants (two per patient) placed in the posterior mandible were recruited. All implants were inserted in pairs in solid D2 bone according to a randomized sequence; the first patient received an IH connection implant on the mesial side while the second patient received an IC connection implant on the mesial side. Each patient received one implant with an IH connection and one with an IC connection, placed side-by-side. Four months after placement, all implants were loaded with single screw-retained ceramic restorations with internal hexagon or conical connections. RMBL and complications, including implant/prosthesis failure, were recorded at the time of implant loading (baseline) and 6, 12, and 36 months after loading. The results revealed no significant between-group differences in RMBL (P = .74), gingival bleeding on probing (P = .29), and complications (P = .32). Thus, the type of internal implant-abutment connection did not affect clinical outcomes, including RMBL and implant/prosthesis failure. Future studies should additionally evaluate long-term prosthesis-related complications such as screw loosening and fracture between the two types of internal connections.

Intra- and inter-observer agreements in detecting peri-implant bone defects between periapical radiography and cone beam computed tomography: A clinical study

Background/purpose

Information regarding agreements between periapical radiograph (PA) and cone beam computed tomography (CBCT) in detecting peri-implant defect is still scarce. The aim of this clinical study was to compare agreements between PA and CBCT in detecting peri-implant bone defect.

Materials and methods

This retrospective clinical study enrolled 32 patients with both PA and CBCT filmed right after implant placement. Four modalities were used for film reading: PA1 (original), PA2 (enhanced brightness/contrast), CBCT1 (selected axial and mesial-distal direction images) and CBCT2 (all data with software). 2 experienced and 2 inexperienced observers scored all films. Intra- and inter-observer agreements were estimated with Cohen's kappa coefficient. Categorized agreements were compared and differences among four modalities were calculated.

Results

Agreements of PA were better than CBCT when detecting peri-implant bone defects in inter-observer agreements (median kappa 0.471 vs. 0.192; p = 0.016). Moreover, agreements in experienced observers were better than inexperienced observers (median kappa 0.883 vs. 0.567; p < 0.001). There was significant difference among four modalities except for experienced observer 2 (p = 0.218).

Conclusion

Agreements of PA are better than CBCT when detecting peri-implant bone defects, especially for inter-observer agreements. Experienced observers are more consistent in assessment than inexperienced ones.

Comparison of the different voxel sizes in the estimation of peri-implant fenestration defects using cone beam computed tomography: an ex vivo study

Background

To examine the influence of voxel sizes to detect of peri-implant fenestration defects on cone beam computed tomography (CBCT) images.

Materials and methods

This study performed with three sheep heads both maxilla and mandible and two types of dental implant type 1 zirconium implant (Zr⁴⁰) (n = 6) and type 2 titanium implant (Ti²²) (n = 10). A total of 14 peri-implant fenestrations (8 buccal surfaces, 6 palatal/lingual surface) were created while 18 surfaces (8 buccal, 10 palatal/lingual) were free of fenestrations. Three observers have evaluated the images of fenestration at each site. Images obtained with 0.75 mm³, 0.100 mm³, 0.150 mm³, 0.200 mm³, and 0.400 mm³ voxel sizes. For intra- and inter-observer agreements for each voxel size, Kappa coefficients were calculated.

Results

Intra- and inter-observer kappa values were the highest for 0.150 mm³, and the lowest in 0.75 mm³ and 0.400 mm³ voxel sizes for all types of implants. The highest area under the curve (AUC) values were found higher for the scan mode of 0.150 mm³, whereas lower AUC values were found for the voxel size for 0.400 mm³. Titanium implants had higher AUC values than zirconium with the statistical significance for all voxel sizes (p ≤ 0.05).

Conclusion

A voxel size of 0.150 mm³ can be used to detect peri-implant fenestration bone defects. CBCT is the most reliable diagnostic tool for peri-implant fenestration bone defects.

Accuracy of cone-beam computed tomography is limited at implant sites with a thin buccal bone: A laboratory study

BACKGROUND

To evaluate whether buccal bone thickness (BBT), implant diameter, and abutment/crown material influence the accuracy of cone-beam computed tomography (CBCT) to determine the buccal bone level at titanium implants.

METHODS

Two implant beds (i.e., narrow and standard diameter) were prepared in each of 36 porcine bone blocks. The implant beds were positioned at a variable distance from the buccal bone surface; thus, resulting in three BBT groups (i.e., >0.5 to 1.0; >1.0 to 1.5; >1.5 to 2.0 mm). In half of the blocks, a buccal bone dehiscence of random extent ("depth") was created and implants were mounted with different abutment/crown material (i.e., titanium abutments with a metal-ceramic crown and zirconia abutments with an all-ceramic zirconia crown). The distance from the implant shoulder to the buccal bone crest was measured on cross-sectional CBCT images and compared with the direct measurements at the bone blocks.

RESULTS

While abutment/crown material and implant diameter had no effect on the detection accuracy of the buccal bone level at dental implants in CBCT scans, BBT had a significant effect. Specifically, when BBT was ≤1.0 mm, a dehiscence was often diagnosed although not present, that is, the sensitivity was high (95.8%), but the specificity (12.5%) and the detection accuracy (54.2%) were low. Further, the average measurement error of the distance from the implant shoulder to the buccal bone crest was 1.6 mm.

CONCLUSIONS

Based on the present laboratory study, BBT has a major impact on the correct diagnosis of the buccal bone level at dental titanium implants in CBCT images; in cases where the buccal bone is ≤1 mm thick, detection of the buccal bone level is largely inaccurate.

Cone beam computed tomography artefacts around dental implants with different materials influencing the detection of peri-implant bone defects

OBJECTIVES

To investigate the diagnostic accuracy of cone beam computed tomography (CBCT) for the diagnosis of peri-implant bone defects of titanium (Ti), zirconium dioxide (ZrO₂ ) or titanium-zirconium (Ti-Zr) alloy implants.

MATERIALS AND METHODS

Ti, Ti-Zr or ZrO₂ implants with two diameters (3.3 mm, 4.1 mm) and one length (10 mm) were inserted in the angle of the mandible of six fresh defrosted pig jaws. Out of the 12 implants inserted, 6 served in the test group with standardized buccal peri-implant bone defects, whereas 6 served as control without bone defects. CBCTs were performed with three acquisition protocols (standard, high and low dose) using two devices. Four observers analysed CBCTs as follows: (a) presence of a peri-implant defect; (b) presence of peri-implant artefacts and impact on defect diagnosis; and (c) linear measurements of buccal peri-implant defect including height and width (in mm).

RESULTS

CBCT device, CBCT settings, implant material, implant diameter and observer background did not significantly influence diagnostic accuracy. The sensitivity and specificity values were high for defect detection. ZrO₂ led to a lower than average diagnostic accuracy (0.781). The linear measurements of peri-implant defect were underestimated by <1 mm on average. The subjective impact of artefacts on defect diagnosis was significantly affected by implant material and observer background.

CONCLUSIONS

CBCT showed high diagnostic accuracy for peri-implant bone defect detection regardless of the device, imaging setting or implant material used. If CBCT is indicated to assess peri-implant bone disease, low dose protocols could be a promising imaging modality.

Does the metal artifact reduction algorithm activation mode influence the magnitude of artifacts in CBCT images?

Purpose

This study was conducted to assess the effectiveness of a metal artifact reduction (MAR) algorithm activated at different times during cone-beam computed tomography (CBCT) acquisition on the magnitude of artifacts generated by a zirconium implant.

Materials and Methods

Volumes were obtained with and without a zirconium implant in a human mandible, using the OP300 Maxio unit. Three modes were tested: without MAR, with MAR activated after acquisition, and with MAR activated before acquisition. Artifacts were assessed in terms of the standard deviation (SD) of gray values and the contrast-to-noise ratio (CNR) in 6 regions of interest with different distances (10 to 35 mm, from the nearest to the farthest) and angulations (70° to 135°) from the implant region.

Results

In the acquisitions without MAR, the regions closer to the implant (10 and 15 mm) had a higher SD and lower CNR than the farther regions. When MAR was activated (before or after), SD values did not differ among the regions (P>0.05). The region closest to the implant presented a significantly lower CNR in the acquisitions without MAR than when MAR was activated after the acquisition; however, activating MAR before the acquisition did not yield significant differences from either of the other conditions.

Conclusion

Both modes of MAR activation were effective in decreasing the magnitude of CBCT artifacts, especially when the effects of the artifacts were more noticeable.