Influence of cone beam computed tomography versus panoramic radiography on the surgical technique of third molar removal: a systematic review.

Panoramic radiography is the standard imaging method for preoperative assessment before lower third molar removal. However, oral surgeons have been using cone beam computed tomography (CBCT) as an additional tool to assess detailed preoperative data, as it provides cross-sectional images. The aim of this systematic review was to determine whether the use of CBCT and the additional information provided modifies the preoperative assessment of lower third molar removal when compared to panoramic radiography and consequently results in a different surgical approach. A search of the PubMed, Embase, Web of Science, Science Direct, and Scopus electronic databases was performed on 30 June 2018, which retrieved 196 records without duplicates. The grey literature was also searched to include any other paper that might meet the eligibility criteria, which resulted in an additional five records. Among these papers, five met all of the eligibility criteria. These five studies included a total of 289 individuals and a total sample of 311 teeth. The findings showed that three-dimensional imaging does not change the surgical approach when compared to panoramic radiography; however it is considered a useful imaging method to understand the relationship between the lower third molars and the mandibular canal.

Treatment of lower lip pits in Van der Woude syndrome: a systematic review.

The presence of lower lip pits in individuals with Van der Woude syndrome (VWS) may cause discomfort due to saliva secretion. Furthermore, one of the main complaints in relation to lip pits is poor aesthetics, which often affects quality of life. The aim of this systematic review was to identify the best technique for the surgical removal of lower lip pits in terms of aesthetic and functional characteristics. A search of the PubMed, Embase, Web of Science, Science Direct, and Scopus databases was performed on December 27, 2016, which retrieved 88 records without duplicates. Among these papers, three ultimately met all eligibility criteria. The three studies included a total of 61 individuals, with follow-up ranging from 6 months to 10 years and sample collection from 10 to 24 years. The findings demonstrated that the outcome of surgical removal of lower lip pits was better with the use of vertical wedge excision, inverted-T lip reduction, Mutaf-Goldstein technique and modified simple excision than with simple excision. Simple excision may result in postoperative complications, such as mucocele and pit recurrence.

CBCT location of the fusion between the buccal and lingual cortical in the mandibular ramus: importance to sagittal split osteotomy.

BACKGROUND: Mandibular Sagittal Split Osteotomy (MSSO) is a popular technique in orthognathic surgery used both to advance and to retreat the mandible. However, MSSO may incur in important complications, such as bad splits and sensorineural injuries. Knowing the location of the fusion between the buccal and lingual cortical (FBLC) in the mandibular ramus and the bone thickness in the region where osteotomies will be performed is determinant in MSSO planning to avoid complications. The aim of this study was to document and evaluate possible differences between sexes regarding the location of the FBLC in relation to the superior cortical of mandibular foramen (MF) and bone thickness in the region of interest for MSSO in a Brazilian population. MATERIAL AND METHODS: Eighty five cone-beam Computed Tomography (CBCT) scans were used to perform linear measurements to determine the location of the FBLC. Bone thickness from the mandibular canal (MC) to the cortical external surfaces and the diameter of the MC were measured at three different points: mandibular ramus (A), mandibular angle (B) and mesial of the second molar (C). RESULTS: The FBLC was located at a mean distance of 8.3 mm from the superior cortical of the MF in males and 8.1 mm in females. There was no difference between males and females regarding the mean bone thickness from the MC to the buccal external surface at all the points investigated (p>0.05). Bone thickness from the lingual external surface to the MC was bigger among females than males in regions B and C (p < 0.05). The diameter of the MC was bigger among males in regions B and C. CONCLUSION: Sexual dimorphism regarding mandibular bone thickness but not regarding the location of FBLC was present. This fundamental knowledge may assist to the panning of MSSO.

Optimization of dental CBCT exposures through mAs reduction.

OBJECTIVES: To investigate the effect of tube current-exposure time (mAs) reduction on clinical and technical image quality for different CBCT scanners, and to determine preliminary minimally acceptable values for the mAs and contrast-to-noise ratio (CNR) in CBCT. METHODS: A polymethyl methacrylate (PMMA) phantom and an anthropomorphic skull phantom, containing a human skeleton embedded in polyurethane, were scanned using four CBCT devices, including seven exposure protocols. For all protocols, the mAs was varied within the selectable range. Using the PMMA phantom, the CNRAIR was measured and corrected for voxel size. Eight axial slices and one coronal slice showing various anatomical landmarks were selected for each CBCT scan of the skull phantom. The slices were presented to six dentomaxillofacial radiologists, providing scores for various anatomical and diagnostic parameters. RESULTS: A hyperbolic relationship was seen between CNRAIR and mAs. Similarly, a gradual reduction in clinical image quality was seen at lower mAs values; however, for several protocols, image quality remained acceptable for a moderate or large mAs reduction compared with the standard exposure setting, depending on the clinical application. The relationship between mAs, CNRAIR and observer scores was different for each CBCT device. Minimally acceptable values for mAs were between 9 and 70, depending on the criterion and clinical application. CONCLUSIONS: Although noise increased at a lower mAs, clinical image quality often remained acceptable at exposure levels below the manufacturer's recommended setting, for certain patient groups. Currently, it is not possible to determine minimally acceptable values for image quality that are applicable to multiple CBCT models.

Unusual bilateral dentigerous cysts in a nonsyndromic patient assessed by cone beam computed tomography.

In the absence of syndromes, bilateral dentigerous cysts (DC) located on the jaws are unusual. In English based language literature review, we only found eight reports of nonsyndromic bilateral dentigerous cyst associated with mandibular third molars. Therefore, we report the unusual occurrence of sizable nonsyndromic bilateral DC associated with mandibular impacted third molars in a 42-year-old Caucasian woman. The lesions were assessed by cone beam computed tomography (CBCT) the right lesion showed approximately 23.64 mm and the left one, 16.57 mm diameter, both located intimately next to the mandibular canal. Bilateral surgical enucleation, related teeth excision of both third molars and plate for fixation placement on the right and bigger lesion, under general anesthesia was the final treatment choice. Clinical, radiographic and histopathological features confirmed diagnose of bilateral dentigerous cyst. Now-a-days, the patient is on 18 months radiograph follow-up with favorable osseous formation with no evidence of recurrence of the cysts.

A comparative evaluation of cone beam CT and micro-CT on trabecular bone structures in the human mandible.

OBJECTIVES: The main purpose of this study was to determine the accuracy of cone beam CT (CBCT) in measuring the trabecular bone microstructure, in comparison with micro-CT. The subobjective was to examine to what extent bone quality assessment is influenced by X-ray tube current and voltage settings as well as soft tissue surrounding the bone. METHODS: Eight human mandibular bone samples were scanned using three different clinical exposure protocol within water (W1-3) and without water (NW1-3) by a high-resolution (80 µm) CBCT machine (3D Accuitomo 170(®); Morita, Kyoto, Japan). Subsequently, the samples underwent micro-CT scanning (SkyScan 1174®; SkyScan, Antwerp, Belgium). After image acquisition, similar volumes of interest of the trabecular structures captured with CBCT and micro-CT were aligned with each other. Segmentation was then performed, and the morphometric parameters were quantified within the volumes of interest by CTAn software (CTAnalyser(®); SkyScan, Antwerp, Belgium). Descriptive statistical analyses and multiple comparisons between all protocols were applied in R software. RESULTS: High positive Pearson's correlation coefficients were observed between CBCT and micro-CT protocols for all tested morphometric indices except for trabecular thickness. No significant differences were observed between all exposure protocols except for trabecular separation. When examining the soft-tissue effect on trabecular bone structures, no significant differences between NW (1-3) and W (1-3) protocols were observed for all variables. CONCLUSIONS: The present study demonstrated the potential of high-resolution CBCT imaging for in vivo applications of quantitative bone morphometry and bone quality assessment. However, the overestimation of morphometric parameters and acquisition settings in CBCT must be taken into account.

An in vitro comparison of subjective image quality of panoramic views acquired via 2D or 3D imaging.

OBJECTIVES: The objective of this study is to compare subjective image quality and diagnostic validity of cone-beam CT (CBCT) panoramic reformatting with digital panoramic radiographs. MATERIALS AND METHODS: Four dry human skulls and two formalin-fixed human heads were scanned using nine different CBCTs, one multi-slice CT (MSCT) and one standard digital panoramic device. Panoramic views were generated from CBCTs in four slice thicknesses. Seven observers scored image quality and visibility of 14 anatomical structures. Four observers repeated the observation after 4 weeks. RESULTS: Digital panoramic radiographs showed significantly better visualization of anatomical structures except for the condyle. Statistical analysis of image quality showed that the 3D imaging modalities (CBCTs and MSCT) were 7.3 times more likely to receive poor scores than the 2D modality. Yet, image quality from NewTom VGi® and 3D Accuitomo 170® was almost equivalent to that of digital panoramic radiographs with respective odds ratio estimates of 1.2 and 1.6 at 95% Wald confidence limits. A substantial overall agreement amongst observers was found. Intra-observer agreement was moderate to substantial. CONCLUSIONS: While 2D-panoramic images are significantly better for subjective diagnosis, 2/3 of the 3D-reformatted panoramic images are moderate or good for diagnostic purposes. CLINICAL RELEVANCE: Panoramic reformattings from particular CBCTs are comparable to digital panoramic images concerning the overall image quality and visualization of anatomical structures. This clinically implies that a 3D-derived panoramic view can be generated for diagnosis with a recommended 20-mm slice thickness, if CBCT data is a priori available for other purposes.

How to assess tonsilloliths and styloid chain ossifications on cone beam computed tomography images.

OBJECTIVE: The aim of this study was to establish an anatomical guideline in cone beam computed tomography (CBCT) images to discriminate soft-tissue calcifications, specifically, tonsilloliths, and styloid chain ossification (SCO) in the multiplanar reconstruction screen of the i-CAT Vision. MATERIALS AND METHODS: We analyzed 100 pairs of CBCT images and panoramic digital radiographies regarding the presence or absence of tonsilloliths and SCO. The intraobserver agreement varied from excellent to good. The statistical analyses included Mann-Whitney test, chi-square test, Spearman test, Student's t-test, and Wilcoxon test. The analyses were repeated without the guideline to verify its effectiveness. RESULTS: A total of 25 tonsilloliths were found in panoramic images while CBCT images revealed 60. Panoramic and CBCT images showed 42% and 63% of patients positive to SCO, respectively. We found a statistically significant difference when comparing the presence of tonsilloliths and SCO between panoramic and CBCT images (Wilcoxon test P < 0.05). The analyses without the guideline showed that the observer tended to diagnoses more false-positive SCO. CONCLUSION: Based on the results, we can suggest that CBCT images are more suitable to differentiate tonsilloliths and SCO than panoramic images. The guideline was more important to diagnosis SCO than tonsilloliths. SCO was misclassified in 34% without the guideline.

Evaluation of proximal caries in images resulting from different modes of radiographic digitalization.

OBJECTIVE: The aim of this study was to evaluate the performances of observers in diagnosing proximal caries in digital images obtained from digital bitewing radiographs using two scanners and four digital cameras in Joint Photographic Experts Group (JPEG) and tagged image file format (TIFF) files, and comparing them with the original conventional radiographs. METHOD: In total, 56 extracted teeth were radiographed with Kodak Insight film (Eastman Kodak, Rochester, NY) in a Kaycor Yoshida X-ray device (Kaycor X-707; Yoshida Dental Manufacturing Co., Tokyo, Japan) operating at 70 kV and 7 mA with an exposure time of 0.40 s. The radiographs were obtained and scanned by CanonScan D646U (Canon USA Inc., Newport News, VA) and Genius ColorPage HR7X (KYE Systems Corp. America, Doral, FL) scanners, and by Canon Powershot G2 (Canon USA Inc.), Canon RebelXT (Canon USA Inc.), Nikon Coolpix 8700 (Nikon Inc., Melville, NY), and Nikon D70s (Nikon Inc.) digital cameras in JPEG and TIFF formats. Three observers evaluated the images. The teeth were then observed under the microscope in polarized light for the verification of the presence and depth of the carious lesions. RESULTS: The probability of no diagnosis ranged from 1.34% (Insight film) to 52.83% (CanonScan/JPEG). The sensitivity ranged from 0.24 (Canon RebelXT/JPEG) to 0.53 (Insight film), the specificity ranged from 0.93 (Nikon Coolpix/JPEG, Canon Powershot/TIFF, Canon RebelXT/JPEG and TIFF) to 0.97 (CanonScan/TIFF and JPEG) and the accuracy ranged from 0.82 (Canon RebelXT/JPEG) to 0.91 (CanonScan/JPEG). CONCLUSION: The carious lesion diagnosis did not change in either of the file formats (JPEG and TIFF) in which the images were saved for any of the equipment used. Only the CanonScan scanner did not have adequate performance in radiography digitalization for caries diagnosis and it is not recommended for this purpose.

High prevalence of oral human papillomavirus infection in Fanconi's anemia patients.

BACKGROUND: Fanconi's anemia (FA) is a rare recessive genetic disorder characterized by bone marrow failure, developmental and congenital abnormalities, which frequently evolves to aplastic anemia and neoplasias, primarily acute leukemia and head-neck carcinomas. Risk of malignancies increases after hematopoietic stem cell transplantation (HSCT), and the role of human papillomavirus (HPV) in FA carcinogenesis have been proposed. OBJECTIVE: To investigate prevalence of oral HPV in FA patients without oral malignant lesions. MATERIALS AND METHODS: After oral examination, 76 subjects without detectable oral malignant lesions were included and classified in four groups: 20 FA submitted to HSCT (I), 22 FA not submitted to HSCT (II), 18 severe aplastic anemia (SAA) submitted to HSCT (III) and 16 healthy subjects (IV). Liquid-based cytology sampling, HPV screening by polymerase chain reaction and genotyping by reverse hybridization were performed. RESULTS: The HPV detection rates were: group I 35%, group II 27.3%, group III 38% and group IV 6.25%. Prevalence of high risk HPV types, mainly HPV16, was detected. Compared with control group, suggestions for increased likelihood of being HPV infected in SAA (OR = 9.55, 95% CI: 1.01-125.41) and FA patients submitted to HSCT (OR = 8.08, 0.83-72.29) emerged. CONCLUSION: Patients without oral malignant lesions submitted to HSCT, have high prevalence of oral HPV. HPV screening and close follow up should be considered in these patients.