Comparison of the influence of FOV sizes and different voxel resolutions for the assessment of periodontal defects

Radiographic diagnosis of periodontal diseases - Current evidence versus innovations

Accurate diagnosis of periodontal and peri-implant diseases relies significantly on radiographic examination, especially for assessing alveolar bone levels, bone defect morphology, and bone quality. This narrative review aimed to comprehensively outline the current state-of-the-art in radiographic diagnosis of alveolar bone diseases, covering both two-dimensional (2D) and three-dimensional (3D) modalities. Additionally, this review explores recent technological advances in periodontal imaging diagnosis, focusing on their potential integration into clinical practice. Clinical probing and intraoral radiography, while crucial, encounter limitations in effectively assessing complex periodontal bone defects. Recognizing these challenges, 3D imaging modalities, such as cone beam computed tomography (CBCT), have been explored for a more comprehensive understanding of periodontal structures. The significance of the radiographic assessment approach is evidenced by its ability to offer an objective and standardized means of evaluating hard tissues, reducing variability associated with manual clinical measurements and contributing to a more precise diagnosis of periodontal health. However, clinicians should be aware of challenges related to CBCT imaging assessment, including beam-hardening artifacts generated by the high-density materials present in the field of view, which might affect image quality. Integration of digital technologies, such as artificial intelligence-based tools in intraoral radiography software, the enhances the diagnostic process. The overarching recommendation is a judicious combination of CBCT and digital intraoral radiography for enhanced periodontal bone assessment. Therefore, it is crucial for clinicians to weigh the benefits against the risks associated with higher radiation exposure on a case-by-case basis, prioritizing patient safety and treatment outcomes.

Effect of a metal artifact reduction algorithm on dehiscence and fenestration detection around zirconia implants with cone beam computed tomography

OBJECTIVE

To assess the efficacy of the metal artifact reduction algorithm (MARA) of the Cranex 3D cone beam computed tomography (CBCT) device in the detection of peri-implant dehiscence and fenestration around zirconia implants.

STUDY DESIGN

In total, 60 implants were placed in bovine ribs. Dehiscence and fenestration defects were created around the implants, after which 60 CBCT images were obtained with and 60 without activation of MARA. Three radiologists examined the images for the presence of defects. The area under the curve (AUC) from receiver operating characteristic analysis, sensitivity, and specificity were calculated to assess the ability to discriminate the presence vs absence of bone defects. One-way analysis of variance was employed to analyze outcome measures. The significance level was established at 5% (α = 0.05).

RESULTS

AUC values indicated excellent discrimination of dehiscence on images with MARA activation and an excellent to outstanding range of discrimination with MARA deactivation. For fenestration, MARA activation and deactivation both led to outstanding discrimination. Sensitivity and specificity values revealed that activation of MARA was helpful in distinguishing the presence vs. absence of dehiscence, while both MARA conditions were helpful for fenestration. However, there were no statistically significant differences between MARA activation and deactivation for any outcome measure (P >.05).

CONCLUSION

CBCT is suitable for detecting peri-implant defects, but MARA application does not significantly affect peri-implant dehiscence and fenestration detection.

Evaluation of the accuracy of cone-beam computed tomography image segmentation of isolated tooth roots based on the dynamic threshold method

OBJECTIVE

Accurate quantification of the root surface area (RSA) plays a decisive role in the advancement of periodontal, orthodontic, and restorative treatment modalities. In this study, we aimed to develop a dynamic threshold-based computer-aided system for segmentation and calculation of the RSA of isolated teeth on cone-beam computed tomography (CBCT) and to assess the accuracy of the measured data.

METHOD

We selected 24 teeth to be extracted, including single-rooted and multi-rooted teeth, from 22 patients who required tooth extraction. In the experimental group, we scanned 24 isolated teeth using CBCT with a voxel size of 0.3 mm. We designed a computer-aided system based on a personalized dynamic threshold algorithm to automatically segment the roots of 24 isolated teeth in CBCT images and calculate the RSA. In the control group, we employed digital intraoral scanner devices to perform optical scanning on 24 isolated teeth and subsequently manually segmented the roots using 3-matic software to calculate the RSA. We used the paired t-test (P < 0.05) and Bland-Altman plots to analyze the consistency of the two measurement methods.

RESULTS

The results of the paired t-test showed that there was no significant difference in the RSAs obtained using the dynamic threshold method and the optical scanning image reconstruction (t = 1.005, P = 0.325 > 0.05). As per the Bland-Altman plot, the results were evenly distributed within the region of ± 1.96 standard deviations of the mean, with no increasing or decreasing trends and good consistency.

CONCLUSION

In this study, we designed a computer-aided root segmentation system based on a personalized dynamic threshold algorithm to automatically segment the roots of isolated teeth in CBCT images with a voxel size of 0.3 mm. We found that the RSA calculated using this approach was highly accurate, and a voxel of 0.3 mm in size could accurately display the surface area data in CBCT images. Overall, our findings in this study provide a foundation for future work on accurate automatic segmentation of tooth roots in full-mouth CBCT images and the computation of RSA.

Understanding root fenestration: A systematic scoping review of prevalence and clinical factors

The aim of this systematic scoping review is to explore the literature on root fenestration prevalence and its possible etiologic, aggravating and predisposing clinical factors. A systematic search was conducted in 5 electronic databases, by two independent reviewers, without any language and date restrictions. Forty-six full-text records were included in the study, out of which 27 were used for prevalence analysis and 42 for clinical factor analysis. The results suggest that the literature is heterogenous, with major differences in the study protocols and results' presentation, providing limited information regarding root fenestration prevalence and possible racial distribution patterns. Further documentation is also required regarding clinical parameters that may affect root fenestration's presence and severity. Despite their few limitations, retrospective cone beam computed tomography studies with high-resolution protocols, as well as open flap studies for direct observation of possible root fenestration sites, seem the most reliable methods to better comprehend its presence and possible distribution patterns.

Reliability of an indirect bone-probing method for diagnosis of labial bone crest level of the mandibular anterior teeth

OBJECTIVES

To evaluate the null hypothesis that there would be no difference between the labial bone crest level of the mandibular anterior teeth evaluated with an indirect bone-probing method (IBP) and cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Twenty-nine adult patients with a mean age of 32.15 ± 8.75 years were enrolled. An IBP based on indirect tactile perception was used to determine the labial bone crest level of the mandibular anterior teeth clinically. Bone crest perception degree, gingival thickness, and patient discomfort during IBP were also recorded. CBCT scans were used to evaluate the level and thickness of the labial bone crest. IBP and CBCT methods were compared statistically. The significance level was set at 5%.

RESULTS

There was a significant difference between the labial bone crest level diagnosed by IBP and CBCT. However, the difference was not clinically significant. IBP and CBCT measurements were significantly and strongly correlated (R = 0.74). Thinner gingival tissue was associated with a higher perception of bone crest. Only two patients reported mild to moderate discomfort during IBP.

CONCLUSIONS

IBP allowed the labial bone crest level to be determined with acceptable clinical accuracy, especially in patients with thinner gingival tissue.

Frequency of root fenestration in a Greek subpopulation: A cone beam computed tomography clinical study

This cone beam computed tomography (CBCT) study aimed to assess the root fenestration (RF) frequency in healthy, intact teeth and analyse their features in a Greek subpopulation. 432 CBCT scans were examined. 5486 teeth were evaluated for RF prevalence. RF prevalence and distribution were recorded for each jaw, tooth group, as well as patient age and sex. RF symmetry, distribution to the affected root surface and the effects of age and sex were evaluated. The prevalence of RF ranged from 0.57% (central incisors) to 7.18% (first premolars) and from 0.48% (second premolars) to 10.79% (lateral incisors) for the maxilla and the mandible, respectively. No symmetrical occurrence of RF was detected. Most RF patients presented one or two defects in both jaws. Types I and IV were the most prevalent in the maxilla, while Types III, II and V were the most prevalent in the mandible. No statistical difference was detected between different sexes and age groups (P > 0.05).

Evaluation of a metal artifact reduction algorithm and an adaptive image noise optimization filter in the estimation of peri-implant fenestration defects using cone beam computed tomography: an in-vitro study

OBJECTIVE

The aim of this study is to assess the effects of metal artifact reduction (MAR) and adaptive image noise enhancer (AINO) in CBCT imaging on the detection accuracy of artificially created fenestration defects in proximity to titanium and zirconium implants in sheep jaw.

METHODS

Six zirconium and 10 titanium implants were planted on mandibular jaws of three sheep, and artificial defects were created. All images were obtained with a standard voxel size (0.150 mm³) and with 4 scan modes: (1) without MAR/without AINO; (2) with MAR/without AINO; (3) without MAR/with AINO; and (4) with MAR/with AINO during CBCT scanning. A total of 60 CBCT scans were produced.

RESULTS

For all types of implants, intra- and inter-observer kappa values were the highest for MAR filter. The scan mode of with MAR filter was found to have the highest area under the curve (AUC), whereas the scan mode of without both MAR and AINO filters was found to have the lowest AUC values with statistical significance (p ≤ 0.05). Titanium implants were found to have higher AUC values than zirconium (p ≤ 0.05).

CONCLUSION

Both MAR module and AINO filters enhance the accuracy of the detection of peri-implant fenestrations; however, the use of MAR filter solely can be recommended for detection of peri-implant fenestrations.

Effect of voxel size on detection of fenestration, dehiscence and furcation defects using cone-beam computed tomography

OBJECTIVES

This study aimed to assess the effect of voxel size on detection of fenestration, dehiscence, and furcation defects using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

This in vitro, experimental study evaluated 4 sheep skulls with both the maxilla and mandible accompanied by the surrounding soft tissue. Fenestration (n = 30), dehiscence (n = 65), and furcation defects (n = 46; 18 grade I, 25 grade II, and 3 grade III) were randomly created by round and needle burs in both jaws, and 40 areas served as control sites. CBCT scans were obtained with 0.300 and 0.150 mm³ voxel sizes and 8 × 11cm² field of view (FOV), and were randomly observed by four observers (two oral and maxillofacial radiologists and two periodontists). The kappa values, sensitivity and specificity were calculated for each voxel size and compared using paired t test.

RESULTS

By an increase in image resolution, diagnostic sensitivity increased while specificity decreased. The kappa values for fenestration (0.602-0.623), and grade III furcation defects (0.903-1.00) were optimal (> 0.6), and almost similar for both voxel sizes. The kappa values for dehiscence, and grades I and II furcation defects were unfavorable (< 0.6) and almost similar for both voxel sizes, except for grade I furcation defects, which had a significant difference in kappa values between the two voxel sizes (0.014 and 0.34).

CONCLUSION

Smaller voxel size had higher sensitivity and lower specificity for detection of all defects except for grade I furcation defects, for which the smaller voxel size had higher sensitivity and higher specificity.

Influence of voxel size on cone beam computed tomography artifacts arising from the exomass

OBJECTIVES

The objective of this study was to evaluate the influence of voxel size on artifacts arising from the exomass in cone beam computed tomography (CBCT).

STUDY DESIGN

An imaging phantom was scanned using 2 CBCT units, each adjusted to 2 voxel sizes: 0.2 and 0.3 mm. From 1 to 3 metal inserts of titanium, cobalt-chromium, or amalgam were placed in the exomass and additional CBCT scans were acquired. Mean voxel gray values were obtained from 16 homogeneous areas of the phantom and averaged, and the standard deviation was calculated to obtain voxel gray value variability. The data were analyzed using 2-way analysis of variance, Tukey, and Dunnett tests (α =.05).

RESULTS

Overall, mean voxel gray values and voxel gray value variability did not differ significantly between CBCT scans obtained with voxel sizes of 0.2 and 0.3 mm for either CBCT model tested (P > .05). Despite some exceptions in which significant differences were observed between the 2 voxel sizes (P < .05), the mean voxel gray values and voxel gray value variability resulting from different metal compositions and, in most situations, for different numbers of metal inserts in the exomass were not affected.

CONCLUSION

Voxel size has little influence on exomass-related CBCT artifacts.

Tomographic evaluation of buccal bone in different skeletal patterns and incisors inclination

OBJECTIVE

The aim of this study was to correlate the absence of BB with skeletal patterns and incisor inclination using cone-beam computed tomography (CBCT).

METHODS

The sample comprised CBCT images of 45 patients undergoing orthodontic treatment. BB was classified in each third of the anterior teeth as critical, slender, regular, and thick. The skeletal pattern was determined by the ANB (A point, nasion, B point) angle and the incisor inclination using the 1.NA and 1.NB measurements and the interincisal angle (1:1).

RESULTS

In both analyses, the skeletal pattern of class II revealed better BB in the cervical and middle thirds than classes I and III. A higher proportion of critical BB was found in the middle thirds, and the apical third presented the best regular and thick BB conditions, mainly class I. Less BB was observed in middle and apical thirds in the upper incisors and in cervical thirds in lower incisors, mostly when they were more upright.

CONCLUSIONS

Knowledge of alveolar bone height and thickness can alter the treatment plan in orthodontics. During orthodontic treatment, more attention should be paid to the lower incisors and vertical teeth because of poor BB conditions, especially in class III skeletal patterns.

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.

Cone beam computed tomography (CBCT) in periodontal diseases: a Systematic review based on the efficacy model

Background

Periodontal diseases are prevalent among adult populations. Its diagnosis depends mainly on clinical findings supported by radiographic examinations. In previous decades, cone beam computed tomography has been introduced to the dental field. The aim of this study was to address the diagnostic efficacy of cone-beam computed tomographic (CBCT) imaging in periodontics based on a systematic search and analysis of the literature using the hierarchical efficacy model.

Methods

A systematic search of electronic databases such as PubMed, Scopus, Web of Science, and Cochrane was conducted in February 2019 to identify studies addressing the efficacy of CBCT imaging in Periodontics. The identified studies were subjected to pre-identified inclusion criteria followed by an analysis using a hierarchical model of efficacy (model) designed for an appraisal of the literature on diagnostic imaging modality. Four examiners performed the eligibility and quality assessment of relevant studies and consensus was reached in cases where disagreement occurred.

Results

The search resulted in 64 studies. Of these, 34 publications were allocated to the relevant level of efficacy and quality assessments wherever applicable. The overall diagnostic accuracy of the included studies showed a low or moderate risk of bias and applicability concerns in the use of CBCT. In addition, CBCT is accurate in identifying periodontal defects when compared to other modalities. The studies on the level of patient outcomes agreed that CBCT is a reliable tool for the assessment of outcomes after the treatment of periodontal defects.

Conclusion

CBCT was found to be beneficial and accurate in cases of infra-bony defects and furcation involvements.

Comparison between different cone-beam computed tomography devices in the detection of mechanically simulated peri-implant bone defects

Purpose

This study compared 2 cone-beam computed tomography (CBCT) systems in the detection of mechanically simulated peri-implant buccal bone defects in dry human mandibles.

Materials and Methods

Twenty-four implants were placed in 7 dry human mandibles. Peri-implant bone defects were created in the buccal plates of 16 implants using spherical burs. All mandibles were scanned using 2 CBCT systems with their commonly used acquisition protocols: i-CAT Gendex CB-500 (Imaging Sciences, Hatfield, PA, USA; field of view [FOV], 8 cm×8 cm; voxel size, 0.125 mm; 120 kVp; 5 mA; 23 s) and Orthopantomograph OP300 (Intrumentarium, Tuusula, Finland; FOV, 6 cm×8 cm; voxel size, 0.085 mm; 90 kVp; 6.3 mA; 13 s). Two oral and maxillofacial radiologists assessed the CBCT images for the presence of a defect and measured the depth of the bone defects. Diagnostic performance was compared in terms of the area under the curve (AUC), accuracy, sensitivity, specificity, and intraclass correlation coefficient.

Results

High intraobserver and interobserver agreement was found (P<0.05). The OP300 showed slightly better diagnostic performance and higher detection rates than the CB-500 (AUC, 0.56±0.03), with a mean accuracy of 75.0%, sensitivity of 81.2%, and specificity of 62.5%. Higher contrast was observed with the CB-500, whereas the OP300 formed more artifacts.

Conclusion

Within the limitations of this study, the present results suggest that the choice of CBCT systems with their respective commonly used acquisition protocols does not significantly affect diagnostic performance in detecting and measuring buccal peri-implant bone loss.

Evaluation of a metal artifact reduction algorithm and an optimization filter in the estimation of peri-implant dehiscence defects by using cone beam computed tomography: an in-vitro study

OBJECTIVES

The aim of this study was to assess the effect of a metal artifact reduction (MAR) algorithm and the adaptive image noise optimizer (AINO) optimization filter in the detection of peri-implant dehiscences with cone beam computed tomography (CBCT).

STUDY DESIGN

Nine implants (3 zirconium, 3 titanium, and 3 zirconium-titanium) were placed in 3 sheep heads. Dehiscences were created on the buccal and lingual/palatal surfaces. A total of 9 defects and 9 controls with no defects were evaluated by 3 observers. Each sheep head was scanned 5 times with 4 scan modes; (1) without MAR/without AINO; (2) with MAR/without AINO; (3) without MAR/with AINO; and (4) with MAR/with AINO. Receiver operating characteristic analysis and weighted kappa coefficients were used to calculate diagnostic efficacy and intra- and interobserver agreements for each implant type and scan mode.

RESULTS

For all implant types, dehiscences were most accurately detected when both MAR and AINO were applied (P ≤ .045). Detection of dehiscences was more accurate with titanium implants (P ≤ .040). There were no significant differences in agreement among and between the observers.

CONCLUSIONS

The use of both MAR and AINO enhanced the detection accuracy of artificially created dehiscences in proximity to implants. Their combined use is recommended for detecting peri-implant dehiscences.

Comparison of in situ cone beam computed tomography scan data with ex vivo optical scan data in the measurement of root surface area

OBJECTIVE

The aim of this study was to compare root surface area (RSA) measurements of single-root teeth in a sheep mandible based on cone beam computed tomography (CBCT) with measurements made with an optical scanner.

STUDY DESIGN

Eight anterior teeth of a sheep cadaver mandible were scanned in situ by using CBCT with 3 different exposure parameters, followed by treatment with smoothing software. The teeth were then extracted and scanned individually with an optical scanner. Three-dimensional digital models of the teeth were reconstructed on the basis of CBCT and optical scanner data. RSA data were calculated, and an equivalence test was used to statistically compare the measurements with significance of difference established at α = 0.05.

RESULTS

The means of the differences between RSA measurements from CBCT and optical scanning ranged from 0.33% to 3.01%. There were no statistically significant differences between the 2 methods. The smoothing parameters for good fitness of the linear regression were determined to be 0.8 for the smooth factor, 8 for iterations, and 0 for compensate shrinkage.

CONCLUSIONS

The proposed CBCT technique to measure RSA is feasible. RSA data obtained from CBCT in situ are as accurate as optical scanner measurements ex vivo.

Accuracy of two different voxel sizes for presurgical evaluation of mandibular osteotomy

The aim of this study was to compare the accuracy of two different voxel resolutions for the preoperative assessment of mandibular osteotomies. The study was conducted on 37 dry adult human mandibles. To obtain measurement standardization, heated gutta-percha cones were placed on the dry mandibles to mark 20 anatomical points. These cones were used for all measurement groups. Cone beam computerized tomography (CBCT) scans of the mandibles were made using 0.200mm³ and 0.400mm³ voxel sizes (Planmeca Promex-3D Helsinki, Finland). The results obtained from these two groups were compared with physical measurements obtained using a digital calliper, in order to analyze their predictive value. In the study, one voxel size did not have supremacy over the other in terms of accuracy. For mandibular osteotomies, 0.400mm³ voxel size can be preferred because of lower radiation dose.

The efficacy of metal artifact reduction (MAR) algorithm in cone-beam computed tomography on the diagnostic accuracy of fenestration and dehiscence around dental implants

BACKGROUND

The aim of the present study was to investigate the impact of metal artifact reduction (MAR) algorithm of cone-beam computed tomography (CBCT) on the diagnostic accuracy of fenestration and dehiscence around dental implants.

METHODS

Twenty-three dental implants were placed adjacent to the dehiscence and 23 adjacent to the fenestration defects on bovine bone blocks. The blocks were scanned with CBCT unit in two modes, with and without MAR algorithm. The area under the receiver operator characteristic (ROC) curves (Az value), specificity, sensitivity, positive predictive value, negative predictive value, and accuracy were determined for all modes.

RESULTS

For both defects, the Az values were higher in off MAR condition. The values of sensitivity, positive predictive value, negative predictive value, and accuracy, were higher in off MAR condition for both defects. However, the specificity in both defects in the two modes was equal.

CONCLUSION

The MAR algorithm in CBCT unit may not be helpful in increasing the diagnostic accuracy of fenestration and dehiscence around dental implants.

The impact of different voxels and exposure parameters of CBCT for the assessment of external root resorptions: A phantom study

This study aimed to compare the effectiveness of the different voxel sizes and imaging parameters of cone beam computed tomography (CBCT) on the determination of external root resorption (ERR). ERRs were created in coronal, middle and apical regions. Depths (0.62-0.73 mm) and diameters (0.68-0.81 mm) of ERRs were measured using a digital calliper. Images were obtained in 0.125, 0.2, 0.25, 0.3 and 0.4 mm³ voxel sizes and at different currents. Data were analysed using Friedman and Wilcoxon signed-rank tests at a level of P < 0.05. There was a difference between the parameters in determining the size of the ERR in coronal and middle regions (P < 0.05), but there was no difference in the apical region (P > 0.05). The change in current and exposure time did not make a difference in determining the dimensions of the ERRs (P > 0.05). Some voxel dimensions were more reliable in determining the depth and diameter of ERR in the coronal and middle region.

Comparison of cone-beam computed tomography with bitewing radiography for detection of periodontal bone loss and assessment of effects of different voxel resolutions: an in vitro study

OBJECTIVE

The aim of the study was to compare intraoral radiographs and CBCT images for detection of horizontal periodontal bone loss, and to investigate the diagnostic effect of different voxel resolutions in CBCT imaging.

METHODS

A total of 240 sites with horizontal bone loss were measured on the buccal, lingual, mesial, and distal surfaces of 60 posterior teeth in four maxillary and six mandibular bones obtained from cadavers (dry skulls). Direct measurements on the dry skulls were accepted as the gold standard values. Measurements on CBCT images at two different voxel resolutions (0.250 and 0.160 mm³) and intraoral bitewing radiographs were compared with one another and with the gold standard values.

RESULTS

The measurements on the CBCT images at two voxel resolutions and bitewing radiographs did not differ significantly (p > 0.05) from the direct measurements on the dry skulls. No significant difference was found between the bitewing radiographs and CBCT images for measurements in the mesial and distal regions (p > 0.05). There was no significant difference between the measurements on the buccal and lingual surfaces at the two different voxel resolutions (p > 0.05).

CONCLUSIONS

CBCT scans are recommended for evaluation of buccal and lingual bone loss to avoid intraoral radiographs that exceed routine examination of interproximal alveolar bone loss. Furthermore, instead of basing the voxel size on the required CBCT scans, it is recommended to select the smallest possible field of view to reduce the dose of radiation.

CBCT assessment of gubernacular canals in relation to eruption disturbance and pathologic condition associated with impacted/unerupted teeth

OBJECTIVES

The aim of this study was to demonstrate the imaging characteristics of gubernacular canals (GCs) in impacted/unerupted permanent teeth and to determine whether these characteristics differ as a result of the presence of eruption disturbances or pathologic conditions associated with impacted/unerupted teeth.

STUDY DESIGN

GCs were retrospectively analyzed by using cone beam computed tomography in 250 patients with 753 impacted/unerupted permanent teeth (105 males, 145 females; mean age, 21.09 ± 14.45 years; range 6-70 years).

RESULTS

The rate of detection of GCs was significantly lower in cases with eruption disturbances than in those without eruption disturbances. An inverse correlation was observed between age and detection of GCs. Similarly, root resorption of adjacent teeth and resorption of impacted/unerupted teeth were associated with lower rates of detection of GCs. However, no association was found for widening of the follicular space. Regression analysis determined disturbed eruption pattern as the most important factor for the absence of GCs.

CONCLUSIONS

The absence of GC may indicate a disturbed eruption pattern of the tooth and may increase the risk of complications related to impaction resulting in a tooth that is more likely to remain unerupted.

Comparison of the burr and chemically induced periodontal defects using different field-of-view sizes and voxel resolutions

OBJECTIVE

This study assessed the use of different voxel resolutions in a cone beam computed tomography (CBCT) unit for the detection of artificially induced periodontal bone defects created using burr, burr and chemicals, and only chemicals.

STUDY DESIGN

Seven dry skulls were used in this study. In total, 65 dehiscence defects, 43 fenestration defects, and 76 control sites with no periodontal defects were examined. Images were obtained from a CBCT unit (3 D Accuitomo; J Morita Mfg. Corp., Kyoto, Japan), using 3 field-of-view (FOV) sizes (4 × 4 cm; 6 × 6 cm; and 8 × 8 cm) and 4 scan modes (standard, high-definition, high-fidelity, and low-dose).

RESULTS

Overall, κ coefficients for interobserver agreement on burr-induced periodontal defects ranged from 0.336 to 0.795, with the lowest κ value (indicating a fair degree of agreement) obtained for images acquired in standard mode with a voxel size of 0.160 mm³. κ coefficients for the detection of periodontal defects were highest (indicating moderate to high degrees of interobserver agreement) for smaller voxel sizes and high-resolution images. Statistical comparison among groups (burr, burr + chemicals, and chemicals only) was performed using 1-way analysis of variance with post hoc tests.

CONCLUSIONS

The CBCT scan mode may affect the diagnosis of periodontal defects. The technique used to create periodontal defects also affected diagnosis. For this kind of experiment, burr-induced or burr + chemical-induced defects should be used, rather than those induced solely using a chemical technique.

Three-dimensional analysis of bone remodeling following ridge augmentation of compromised extraction sockets in periodontitis patients: A randomized controlled study

OBJECTIVES

The aim of this study was to analyze linear and volumetric hard tissue changes in severely resorbed alveolar sockets after ridge augmentation procedure and to compare them with spontaneous healing using three-dimensional cone beam computed tomography (CBCT).

MATERIAL AND METHODS

Thirty patients (mean age 53.2 ± 6.3 years) requiring tooth extraction for advanced periodontitis were randomly allocated to test and control groups. The test sites were grafted using a collagenated bovine-derived bone (DBBM-C) covered with a collagen membrane, while control sites had spontaneous healing. Both groups healed by secondary intention. Linear and volumetric measurements were taken on superimposed CBCT images obtained after tooth extraction and 12 months later.

RESULTS

Greater horizontal shrinkage, localized mainly in the crestal zone, was observed in the control group (4.92 ± 2.45 mm) compared to the test group (2.60 ± 1.24 mm). While both groups presented a rebuilding of the buccal wall, it was most pronounced in the grafted sockets (2.50 ± 2.12 mm vs. 0.51 ± 1.02 mm). A significant difference was also registered in the percentage of volume loss between grafted and non-grafted sites (9.14% vs. 35.16%, p-value <.0001).

CONCLUSION

Alveolar sockets with extensive buccal bone deficiencies undergo significant three-dimensional volumetric alterations following natural healing. The immediate application of a slow-resorbing xenograft with a covering collagen membrane seems to be effective in improving alveolar ridge shape and dimensions, thus potentially reducing the need for adjunctive regenerative procedures at the time of implant placement.

Engineered scaffolds and cell-based therapy for periodontal regeneration

BACKGROUND

The main objective of regenerative periodontal therapy is to completely restore the periodontal tissues lost. This review summarizes the most recent evidence in support of scaffold- and cell-based tissue engineering, which are expected to play a relevant role in next-generation periodontal regenerative therapy.

METHODS

A literature search (PubMed database) was performed to analyze more recently updated articles regarding periodontal regeneration, scaffolds and cell-based technologies.

RESULTS

Evidence supports the importance of scaffold physical cues to promote periodontal regeneration, including scaffold multicompartmentalization and micropatterning. The in situ delivery of biological mediators and/or cell populations, both stem cells and already differentiated cells, has shown promising in vivo efficacy.

CONCLUSIONS

Porous scaffolds are pivotal for clot stabilization, wound compartmentalization, cell homing and cell nutrients delivery. Given the revolutionary introduction of rapid prototyping technique and cell-based therapies, the fabrication of custom-made scaffolds is not far from being achieved.

Influence of acquisition parameters on the evaluation of mandibular third molars through cone beam computed tomography

OBJECTIVES

The aim of the study was to assess the influence of cone beam computed tomography (CBCT) acquisition parameters on the evaluation of mandibular third molars and their relationship to the mandibular canal.

STUDY DESIGN

Eight dry human mandibles with 13 mandibular third molars were scanned with one CBCT unit. Voxel size (0.2 and 0.3 mm), field of view (FOV) size (12 × 8.5 cm and 5 × 5 cm), and number of basis images (450 and 720) were the variables studied. Two examiners evaluated the images, and the resulting data were compared through McNemar, McNemar-Bowker, and Student t tests. Additionally, dosimetry was determined for all protocols tested, and radiation doses were compared through analysis of variance.

RESULTS

The variables did not influence evaluation of mandibular third molars, except for voxel size, when assessing contact between the tooth and the mandibular canal (P = .021). Although FOV and number of basis images affected radiation dose, voxel size did not.

CONCLUSIONS

FOV size and number of basis images did not influence the evaluation of mandibular third molars and their relationship to the mandibular canal in the CBCT unit used. Conversely, smaller voxel size affected the assessment of contact between the tooth and the mandibular canal. In units in which voxel size does not influence radiation dose, the most appropriate CBCT protocol is the one using a smaller voxel size and delivering the lowest radiation dose to the patient.

Detection of simulated periodontal defects using cone-beam CT and digital intraoral radiography

OBJECTIVES:

This study sought to assess the diagnostic value of CBCT and digital intraoral radiography for the detection of periodontal defects in the sheep mandible.

METHODS:

In this in vitro study, 80 periodontal defects including Grades I, II and III furcation involvements, one-, two-, three-wall and trough-like infrabony defects, fenestration and dehiscence were artificially created in the sheep mandible by burr. Intraoral digital radiographs using photostimulable phosphor plates and CBCT scans were obtained. Three periodontists evaluated the images for the presence and type of defects. The results were compared with the gold standard (photographs of the created defects).

RESULTS:

CBCT scans were significantly superior to digital radiographs for the detection of Grade I furcation involvements, three-wall defects, fenestrations and dehiscence (p < 0.05). No significant difference was noted between CBCT and digital radiography for the detection of Grades II and III furcation involvements, one-wall, two-wall and trough-like defects (p-value > 0.05).

CONCLUSIONS:

CBCT was superior to digital intraoral radiography for the detection of Grade I furcation involvements, three-wall defects, dehiscence and fenestrations.

Effect of Cone-Beam Computed Tomography Field of View and Acquisition Frame on the Detection of Chemically Simulated Peri-Implant Bone Loss In Vitro

BACKGROUND

The aim of this study is to determine the influence of field of view (FOV) and number of acquisition projection images (frames) on the detection of chemically simulated peri-implant defects by cone-beam computed tomography (CBCT) using an in vitro bovine rib bone model.

METHODS

Eighty implants were placed in bovine ribs in which small and large bone defects were created using 70% perchloric acid. CBCT images were acquired at three acquisition protocols: protocol 1 (FOV 4 × 4 cm, 0.08-mm voxel size, 1,009 frames [high fidelity]; protocol 2 (same as protocol 1 except 512 frames [standard]); and protocol 3 (FOV 14 × 5 cm, 0.25-mm voxel size; high fidelity). Two oral and maxillofacial radiologists (OMRs) and two oral and maxillofacial surgeons (OMSs) rated the presence or absence of bone defects on a five-point scale. κ and area under the curve (AUC) were calculated and compared using analysis of variance with post hoc Tukey test at P ≤ 0.05.

RESULTS

Intra- and interobserver agreement for OMRs ranged from moderate to good and from slight to moderate for OMSs. For the detection of small lesions, protocol 1 (AUC 0.813 ± 0.045) provided higher detection rates than protocol 2 (AUC 0.703 ± 0.02) and protocol 3 (AUC 0.773 ± 0.55) [F(2,9) = 1.6377]. For larger defects, the trends were similar, with protocol 1 (AUC 0.852 ± 0.108) providing higher detection rates than protocol 2 (AUC 0.730 ± 0.045) and protocol 3 (AUC 0.783 ± 0.058) [F(2,9) = 1.9576].

CONCLUSION

Within the limits of this study, optimal detection of chemically simulated pericircumferential implant crestal bone defects is achieved at the least radiation detriment using the smallest FOV, the highest number of acquisition frames, and the smallest voxel.