Radiographic diagnosis of dental restoration misfit: a systematic review

Efficacy of a radiographic film holder adapter in generating radiographs of dental implants with improved geometric accuracy and sharpness

STATEMENT OF PROBLEM

Some radiographic film holders produce radiographs with geometric distortion that may interfere with diagnosis. However, whether the distortion can be corrected by adjusting the design of the radiographic film holder is unclear.

PURPOSE

The purpose of the study was to develop an adapter for a radiographic film holder model aiming to generate radiographs with greater sharpness and a more accurate geometric representation of dental implants.

MATERIAL AND METHODS

The 2-piece adapter was designed using the SketchUp software program and was 3-dimensionally (3D) printed. Implants with internal conical connections were installed in 19 maxillary prototypes in the central incisor region. Five dentists obtained 285 digital periapical radiographs with 3 different radiographic film holders: standard Cone Indicator, Rinn XCP, and adapted Cone Indicator. They then evaluated the radiographic sharpness of the implants threads and their dimensions using the ImageJ software program. The data were analyzed using the Friedman test with the Durbin-Conover post hoc test and MANOVA with the Tukey post hoc test (α=.05).

RESULTS

On the mesial surface of the implants, the threads were sharper for the adapted than for the standard Cone Indicator radiographic film holder (P<.05). The adapted Cone Indicator showed a smaller difference between the radiographic and actual implant diameters compared with the Rinn XCP and standard Cone Indicator radiographic film holders (P<.05).

CONCLUSIONS

The developed adapter provided radiographs of dental implants with improved sharpness and geometric accuracy.

Does enhancement filter application increase the diagnostic accuracy of misfit detection at the implant-prosthesis interface?

STATEMENT OF PROBLEM

Misfits at the implant-prosthesis interface may increase complications in dental implants and affect peri-implant tissue health. Periapical radiographs are the most used imaging examinations for detecting misfits at the implant-prosthesis interface, although digital systems have largely replaced film-based radiographs. Whether postprocessing tools such as enhancement filters assist diagnosis by highlighting misfits is unclear.

PURPOSE

The purpose of this in vitro study was to assess the influence of enhancement filter application in the diagnostic accuracy of misfit detection at the implant-prosthesis interface.

MATERIAL AND METHODS

A total of 32 dental implants were placed in dry human mandibles. A polyester strip was inserted at the implant-prosthesis interface to simulate a 50-μm misfit; prosthetic crowns installed directly on the implant platforms were used as controls. Standard paralleling periapical images were acquired by using a semidirect system (photostimulable phosphor plate) with the application of Highlight, Invert, and Colorization filters, as well as a direct system (metal oxide complementary semiconductor sensor) with filters Sharpness 3, Invert, and Pseudocolorization. Oral radiologists evaluated the images with and without the application of filters. The areas under the receiver operating characteristics curves (Az values), sensitivity, specificity, accuracy, positive predictive value, and negative predictive values were calculated. The Az values were compared with the receiver operating characteristic (ROC) curves comparison test of the Epidat 3.1 software (α=.05).

RESULTS

Although images without filter application presented descriptively higher diagnostic values than those with filter application, the Az values for images with and without filter application in both semidirect and direct systems showed no significant differences (P>.05).

CONCLUSIONS

Enhancement filter application did not significantly influence the diagnostic accuracy of misfit detection at the implant-prosthesis interface.

Influence of the Method of Calculating the Effective Atomic Number on the Estimate of Fluorescence Yield for Metal Alloys of Biomedical Interest

ABSTRACT

This study evaluates the influence of the method used to calculate the effective atomic number (Z eff ) on the estimate of secondary radiation yielded under kilovoltage x-ray beams by metal alloys with a wide range of biomedical applications. Two methods for calculating Z eff (referred to here as M 1 and M 2 ) are considered, and six metallic alloys are investigated: Ti-6Al-4 V, Co-Cr-Mo, Ni-Cr-Ti, Ni-Cr, Co-Cr-Mo-W, and Ag 3 Sn-Hg (amalgam). The results indicate significant differences in the estimates of fluorescence yield depending on the method used to estimate Z eff for each metallic alloy. Both the choice of the calculation method for Z eff and the energy ranges of the incident radiation are essential factors affecting the behavior of alloys in terms of fluorescence production. Our results may guide the selection of the best material for a biomedical application. The metallic alloys simulated here show equivalences and discrepancies that depend on the method used to estimate Z eff and the energy range of the incident photons. This finding allows for the creation of combinations of alloys and methods for calculating Z eff and the photon energy to maximize safety and minimize cost.

Detection of misfits at the abutment-prosthesis interface in the esthetic zone: Implications of the radiographic technique and the magnitude of the misfit

STATEMENT OF PROBLEM

Misfits in the abutment-prosthesis interface represent a setback for implant-supported prostheses. Periapical radiographs have been used as an auxiliary method in the evaluation of prosthesis fit to the abutments; however, the evidence supporting the use of this method is still restricted to studies of low to moderate quality. Furthermore, studies on the diagnostic accuracy of different periapical techniques used to detect misfits in the abutment-prosthesis interface, especially in the esthetic zone, are lacking.

PURPOSE

The purpose of this in vitro study was to assess the discrimination power of 3 periapical radiographic techniques in detecting misfits at the abutment-prosthesis interface in the esthetic zone and evaluate whether the magnitude of the misfit influenced the diagnosis.

MATERIAL AND METHODS

A total of 15 implants with an internal conical connection were installed in the central incisor region in polyamide jaws. Custom ceramic copings for cemented crowns were made by using a computer-aided design and computer-aided manufacturing (CAD-CAM) system. Misfits of 50, 100, and 150 µm were simulated by interposing 1, 2, or 3 50-μm-thick polyester strips at the abutment-prosthesis interface; the absence of the strip represented the control group. Digital radiographs were obtained by using film holders for the following periapical techniques: bisecting angle (PBA), standard paralleling (PSP), and modified paralleling (PMP). Two radiologists and 1 prosthodontist evaluated a total of 180 radiographs. The values of the area under the receiver operating characteristic curve (Az) were regarded as a measure of diagnostic accuracy and subjected to the Friedman test with post hoc Durbin-Conover (α=.05).

RESULTS

The PSP (Az=0.873) had higher Az values than the PBA (Az=0.753) for the 50-μm misfits (P<.05). Larger misfits resulted in greater accuracy than smaller misfits (P<.05). Interactions between the factors radiographic technique and misfit magnitude resulted in statistically significant differences for all comparisons (P<.05), except between the PSP for the 100-μm misfits (Az=0.976) and the PMP for the 150-μm misfits (Az=0.998).

CONCLUSIONS

The PSP was more accurate than the PBA in detecting the 50-µm misfits at the abutment-prosthesis interface; larger misfits resulted in more accurate diagnoses, regardless of the technique used.

Misfit of Implant-Supported Zirconia (Y-TZP) CAD-CAM Framework Compared to Non-Zirconia Frameworks: A Systematic Review

Objective: The aim of the study was to systematically review the overall outcomes of studies comparing the misfit of yttria-stabilized zirconia (Y-TZP) CAD-CAM implant-supported frameworks with frameworks fabricated with other materials and techniques. Methods: An electronic literature search of English literature was performed using Google Scholar, Scopus, Web of Science, MEDLINE (OVID), EMBASE, and PubMed, using predetermined inclusion criteria. Specific terms were utilized in conducting a search from the inception of the respective database up to May 2022. After the search strategy was applied, the data were extracted and the results were analyzed. The focused question was: Is the misfit of the implant-supported zirconia CAD-CAM framework lower than that of non-Y-TZP implant-supported fixed restorations? Results: Eleven articles were included for qualitative assessment and critical appraisal in this review. In the included studies, Y-TZP CAD-CAM implant-supported frameworks were compared to Titanium (Ti), Ni-Cr, Co-Cr, PEEK and high-density polymer, and cast and CAD-CAM frameworks. The studies used scanning electron microscopy, one-screw tests, digital or optical microscopy, 3D virtual assessment, and replica techniques for analyzing the misfit of frameworks. Six studies showed comparable misfits among the Y-TZP CAD-CAM frameworks and the controls. Three studies showed higher misfits for the Y-TZP CAD-CAM frameworks, whereas two studies reported lower misfits for Y-TZP CAD-CAM implant frameworks compared to controls. Conclusion: Y-TZP CAD-CAM implant-supported frameworks have comparable misfits to other implant-supported frameworks. However, due to heterogeneity in the methodologies of the included studies, the overall numerical misfit of the frameworks assessed in the reviewed studies is debatable.

Misfit detection in implant-supported prostheses of different compositions by periapical radiography and cone beam computed tomography: An in vitro study

STATEMENT OF PROBLEM

Misfits at the implant-abutment joint (IAJ) can cause the biological and mechanical failure of implant therapy. Standard parallel periapical radiography (PERI) is the method of choice for assessing the fitting of implant-supported prostheses. Although current guidelines do not support the use of cone beam computed tomography (CBCT) solely for misfit detection, CBCT scans can also register misfits as imaging findings. Whether the material used for prostheses manufacturing influences misfit appearance in PERI and CBCT images is unknown.

PURPOSE

The purpose of this in vitro study was to assess the influence of the type of prosthesis material on misfit detection at the IAJ by using PERI and CBCT.

MATERIAL AND METHODS

Thirty-two implants with an external hexagon connection were placed in dried human mandibles. Implant-supported crowns were manufactured with different materials and allocated to 3 experimental groups: metal-ceramic (MC), titanium abutment veneered with acrylic resin (TIT), and zirconia abutment veneered with glass-ceramic (ZIR). All crowns were installed both with and without a simulated 200-μm-thick gap at the IAJ (n=64) and were assessed by PERI and CBCT scans. Four dentists evaluated the images for the presence or absence of misfit. Statistical analysis included the Kappa test and areas under the receiver operating characteristics curve (Az values) comparisons (α=.05).

RESULTS

Kappa values indicated almost perfect intraevaluator and interevaluator reproducibility for PERI and ranged from fair to almost perfect for CBCT. For PERI, Az values were not significantly different among the MC (0.995), TIT (0.997), and ZIR groups (1.000) (P>.05). Regarding CBCT, the Az values found for TIT (0.941) and MC (0.890) were significantly higher than for ZIR (0.762) (P<.05). Az values for PERI were significantly higher than for CBCT (P<.05).

CONCLUSIONS

The type of prosthesis material did not influence misfit detection at the IAJ with PERI; however, ZIR had lower diagnostic accuracy than TIT and MC implant-supported crowns with CBCT.

Accuracy of various imaging methods for detecting misfit at the tooth-restoration interface in posterior teeth

Purpose

The present study aimed to evaluate which of the following imaging methods best assessed misfit at the tooth-restoration interface: (1) bitewing radiographs, both conventional and digital, performed using a photostimulable phosphor plate (PSP) and a charge-coupled device (CCD) system; (2) panoramic radiographs, both conventional and digital; and (3) cone-beam computed tomography (CBCT).

Materials and Methods

Forty healthy human molars with class I cavities were selected and divided into 4 groups according to the restoration that was applied: composite resin, composite resin with liner material to simulate misfit, dental amalgam, and dental amalgam with liner material to simulate misfit. Radiography and tomography were performed using the various imaging methods, and the resulting images were analyzed by 2 calibrated radiologists. The true presence or absence of misfit corresponding to an area of radiolucency in regions subjacent to the esthetic and metal restorations was validated with microscopy. The data were analyzed using a receiver operating characteristic (ROC) curve, and the scores were compared using the Cohen kappa coefficient.

Results

For bitewing images, the digital systems (CCD and PSP) showed a higher area under the ROC curve (AUROC) for the evaluation of resin restorations, while the conventional images exhibited a larger AUROC for the evaluation of amalgam restorations. Conventional and digital panoramic radiographs did not yield good results for the evaluation of resin and amalgam restorations (P<.05). CBCT images exhibited good results for resin restorations (P>.05), but showed no discriminatory ability for amalgam restorations (P<.05).

Conclusion

Bitewing radiographs (conventional or digital) should be the method of choice when assessing dental restoration misfit.

Diagnostic accuracy of 4 intraoral radiographic techniques for misfit detection at the implant abutment joint

STATEMENT OF PROBLEM

A misfit or gap at the implant-abutment joint (IAJ) requires detection as it may compromise the health of the peri-implant tissue. However, which radiographic technique provides the most orthogonal relationship between the central beam and the implant/image receptor is unclear.

PURPOSE

The purpose of this in vitro study was to evaluate the diagnostic accuracy of 4 intraoral radiographic techniques on misfit detection at the IAJ.

MATERIAL AND METHODS

Twenty implants were placed in polyamide jaws, and customized dental implant abutments with a metal collar were installed. Different gaps were simulated by placing one or three 50-μm-thick polyester strips at the IAJ; the absence of the strip represented the control group (no gap). The 4 radiographic techniques were evaluated by using different film holders: a periapical with bisecting angle (PBA), a bitewing interproximal (BI), a periapical with standard paralleling (PSP), and a periapical with modified paralleling (PMP) holder (with a custom-made paralleling index). A total of 240 digital radiographs were evaluated by 4 clinicians experienced with dental implants. Differences were evaluated by using receiver operating characteristic (ROC) curves (Az) and Fisher tests (α=.05). Diagnostic values (sensitivity, specificity, accuracy, and positive and negative predictive values) were also obtained. The Kappa test was used to assess intra- and interevaluator reproducibility, which ranged from moderate to almost perfect.

RESULTS

All diagnostic values, except specificity, were lower for the PBA technique for both the 50- and 150-μm gaps. Az values for the PBA technique were significantly lower than those obtained for the other 3 techniques (P<.05), which did not differ from each other. The 150-μm gaps were more easily detected than the 50-μm gaps only for PBA (P<.05).

CONCLUSIONS

The BI, PSP, and PMP techniques detected misfits at the IAJ most accurately. The PBA technique is not recommended for this purpose.