Recurrence rate of odontogenic myxoma after different treatments: a systematic review.

Our aim was to establish the recurrence rate of odontogenic myxoma after different treatments. Our search covered papers from 1972-2017 from different sources. The papers were evaluated and critically appraised by two independent investigators. The recurrence rate and 95% CI were calculated in relation to each specific treatment, and the chi squared test was calculated to find out if there was any significant difference in the recurrence rate between conservative treatment and resection. The overall recurrence rate was 5 of 39 patients (13%) during a mean follow up period of 10 years. With conservative treatment the recurrence rate was 4/22 (19%) (mean follow up 11 years) and after resection it was 1/17 (6%) (mean follow up nine years). Maxillary lesions were more likely to recur than mandibular ones. Quality of life variables such as disfigurement and neural deficit were more common after resection than with conservative treatment. The frequency of recurrence was relatively low over 10 years' follow up, irrespective of whether resection or a more conservative approach was used, despite being slightly lower (as might be expected) after resection. Conservative treatment should be considered first to avoid resection-associated morbidity and the effect on the quality of life. Maxillary lesions have more room to spread before they are clinically evident, making them difficult to treat optimally and contributing to the recurrence rate.

Cone Beam Computed Tomographic imaging in orthodontics.

Over the last 15 years, cone beam computed tomographic (CBCT) imaging has emerged as an important supplemental radiographic technique for orthodontic diagnosis and treatment planning, especially in situations which require an understanding of the complex anatomic relationships and surrounding structures of the maxillofacial skeleton. CBCT imaging provides unique features and advantages to enhance orthodontic practice over conventional extraoral radiographic imaging. While it is the responsibility of each practitioner to make a decision, in tandem with the patient/family, consensus-derived, evidence-based clinical guidelines are available to assist the clinician in the decision-making process. Specific recommendations provide selection guidance based on variables such as phase of treatment, clinically-assessed treatment difficulty, the presence of dental and/or skeletal modifying conditions, and pathology. CBCT imaging in orthodontics should always be considered wisely as children have conservatively, on average, a three to five times greater radiation risk compared with adults for the same exposure. The purpose of this paper is to provide an understanding of the operation of CBCT equipment as it relates to image quality and dose, highlight the benefits of the technique in orthodontic practice, and provide guidance on appropriate clinical use with respect to radiation dose and relative risk, particularly for the paediatric patient.

Comparative diagnostic yield of cone beam CT reconstruction using various software programs on the detection of vertical root fractures.

OBJECTIVES: To evaluate the effect on diagnostic yield in the detection of experimentally induced vertical root fractures on cone beam CT images using four dental software program. METHODS: 190 single-rooted extracted human teeth were divided into three groups according to the pulp canal status: unrestored (UR), filled with gutta-percha (GP) and restored with a metallic custom post (Post). One-half of the sample of each group was artificially fractured and the segments repositioned. All teeth were scanned on a cone beam CT device at 0.2 mm nominal voxel resolution (i-CAT Platinum; Imaging Sciences International, Hatfield, PA). The data were exported as digital imaging and communications in medicine files and imported into Dolphin Imaging & Management Solutions, v. 11.5 (Patterson Dental Supply Inc., St Paul, MN), InVivoDental, v. 5.0 (Anatomage Inc., San Jose, CA) and Kodak Dental Imaging Software 3D module, v. 2.1.11 (Carestream Health Inc., Rochester, NY) software. Cross-sectional images in the acquisition (using Xoran CAT™, v. 3.0.34 software; Xoran Technologies, Ann Arbor, MI) and additional software were presented to three calibrated oral radiologists who rated the presence or absence of root fracture on a five-point scale. Receiver operating characteristic analysis was performed, and treatment comparisons compared by analysis of variance and pairwise comparisons were performed using Tukey's test at an a priori value of α < 0.05%. RESULTS: All dental software performed equally at detecting fractures. Fractures were significantly more difficult to detect when posts were present. CONCLUSIONS: The diagnosis of root fracture is software-independent. The presence of an intracanal metallic post significantly decreases the detection of artificially created root fractures.

Responsible use of cone beam computed tomography: minimising medico-legal risks.

This communication highlights some of the ethical and possible legal responsibilities which pertain to the taking, reading, reporting, and communication of findings from cone-beam computed tomography (CBCT) scans. The importance of knowledge of head and neck anatomy and pathology to reduce the likelihood of incorrect interpretation is emphasised. Failure to detect critical findings in any diagnostic image can potentially result in medico-legal consequences. CBCT is no exception to this rule. Dental schools are advised to include CBCT imaging as a diagnostic tool in their under- and postgraduate curricula thereby equipping graduates to use 3D imaging in general and CBCT in particular. Existing dental practitioners are advised to seek continuing education on 3D imaging as part of their required lifelong learning.

Maxillofacial cone beam computed tomography: essence, elements and steps to interpretation.

Maxillofacial cone beam computed tomography (CBCT) is one of the most significant advances in dental imaging since rotational panoramic radiography. While the acquisition of CBCT data is technically simple, numerous parameters should be considered so that CBCT imaging is performed appropriately and 'task specific'. This involves an understanding of not only exposure (e.g. geometric and software parameters to minimize patient dose, while sustaining diagnostic image quality) but also image formatting options to maximize image display. CBCT images contain far more detailed information of the maxillofacial region than do panoramic or other 2-D images and necessitate a thorough knowledge of the 3-D anatomy of the region and considerations of variability in the range of the anatomically normal. These principles, procedures and protocols, together with the interpretation of CBCT images form the basis of best practices in maxillofacial CBCT imaging. This communication aims to provide: (1) an overview of the fundamental principles of operation of maxillofacial CBCT technology; (2) an understanding of 'task specific' equipment, image selection and image display modes; and (3) a systematic methodology for sequencing interpretation of CBCT images.

Guidelines for the safe use of dental and maxillofacial CBCT: a review with recommendations for South Africa.

The aim of this manuscript is to provide the South African dental profession with guidelines and recommendations on the safe and responsible clinical use of cone beam computed tomography (CBCT) equipment. Dental practitioners who prescribe and refer patients for CBCT examinations as well as those who operate CBCT systems and interpret the images, share responsibility for the use of CBCT systems. Applicable information pertaining to the current status of the use of CBCT was reviewed, and the Directorate of Radiation Control of the Department of Health, South Africa, was invited to participate in the development of evidence-based guidelines on the safe use of cone beam computed tomography in dentistry. These guidelines establish a basis for discussions that are likely to lead to legislation.

Time and motion study: a comparison of two photostimulable phosphor imaging systems used in dentistry.

OBJECTIVES: To compare two photostimulable phosphor (PSP) dental radiographic systems in terms of time efficiency in making full mouth intraoral X-ray surveys (FMS). METHODS: PSP systems compared were (1) DenOptix) (Kavo/Gendex, Des Plaines, IL) and (2) ScanX) (Air Techniques, Hicksville, NY). Twenty one FMS of a DXTRR) Manikin (Dentsply, Des Plaines, IL) were made with each of the systems. Time for each procedural step was determined using a stopwatch. Steps studied were: (1) plate erasure; (2) packaging; (3) positioning/exposure; (4) unpacking, loading processor, scanning; and (5) image transfer to virtual FMS mount. The first six test runs for each system were excluded to eliminate the learning curve period influencing results. An independent groups t-test was employed for statistical analysis. The a priori was set at P< or =0.05. RESULTS: The total time involved in producing a FMS was not proven to be statistically significant comparing DenOptix) and ScanX). The mean procedure time for DenOptix) was 31.2 min; for ScanX) it was 27.1 min. While the processing time with ScanX) (mean time: 3.9 min) was shorter than for DenOptix) (mean time =7.8 min), the opposite was true for the image transfer to FMS format with the time much shorter with DenOptix) using VixWin) software (mean time =2.0 min) compared with ScanX) using Vipersoft) (mean time =3.9 min). The differences between the systems for these two steps did prove to be statistically significant (P< or =0.05). CONCLUSIONS: Although the mean time to make a FMS was slightly shorter on average with ScanX) than DenOptix), this difference was not proven to be statistically significant (P>0.05) in terms of time efficiency in producing a FMS.

Antibiotic use for irreversible pulpitis.

BACKGROUND: Irreversible pulpitis, which is characterised by acute and intense pain, is one of the most frequent reasons that patients attend for emergency dental care. Apart from removal of the tooth the customary way of relieving the pain of irreversible pulpitis is by drilling into the tooth, removing the inflamed pulp (nerve) and cleaning the root canal. However, a significant minority of dentists continue to prescribe antibiotics to stop the pain of irreversible pulpitis. OBJECTIVES: The objective of this review was to provide reliable evidence regarding the effectiveness of prescribing systemic antibiotics for irreversible pulpitis by comparing clinical outcomes expressed as pain relief. SEARCH STRATEGY: We searched the following databases: Cochrane Oral Health Group Trials Register and Pain, Palliative Care and Supportive (PaPaS) Care Group Trials Register to 6th September 2004; the Cochrane Central Register of Controlled Trials (CENTRAL) The Cochrane Library Issue 3 2004; MEDLINE (1966 to 6th September 2004); EMBASE (1980 to week 36 2004). SELECTION CRITERIA: This review includes one randomised controlled trial which compared pain relief with systemic antibiotics and analgesics, against placebo and analgesics in the acute preoperative phase of irreversible pulpitis. DATA COLLECTION AND ANALYSIS: Only one trial is included in this review, therefore pooling of data from studies was not possible and a descriptive summary is presented. MAIN RESULTS: One trial involving 40 participants was included in this review. There was a close parallel distribution of the pain ratings in both the intervention and placebo groups over the 7 day study period. The between-group differences in sum pain intensity differences (SPID) for the penicillin group were (6.0+/-10.5), and for placebo (6.0+/-9.5) P = 0.776. The sum pain percussion intensity differences (SPPID) for the penicillin group were (3.5+/-7.5) and placebo (2.0+/-7.0) P = 0.290, with differences as assessed by the Mann-Whitney-Wilcoxon test considered to be statistically significant at P < 0.05. There was no significant difference in the mean total number of ibuprofen tablets (P = 0.839) and Tylenol tablets (P = 0.325), in either group over the study period. The administration of penicillin over placebo did not appear to significantly reduce the quantity of analgesic medication taken (P > 0.05) for irreversible pulpitis. AUTHORS' CONCLUSIONS: This review which was based on one methodologically sound but low powered small sample trial provided some evidence that there is no significant difference in pain relief for patients with untreated irreversible pulpitis who did or did not receive antibiotics in addition to analgesics.

Impact of ambient lighting intensity and duration on the signal-to-noise ratio of images from photostimulable phosphor plates processed using DenOptix and ScanX systems.

OBJECTIVES: To evaluate the impact on photostimulable phosphor (PSP) image signal-to-noise ratio (SNR) of pre-scanning ambient lighting exposures. METHOD: PSP imaging plates (IPs) were exposed to different radiation exposures to achieve flat field images. The exposed IPs were subjected variously to visible light of different intensities (300, 150 or 20 lux) for durations ranging from < 10 s to 120 s. They were processed using laser scanners from two systems for further comparison (DenOptix versus ScanX). Histogram analysis was performed in each case and mean pixel value and its standard deviation were used as surrogates to assess SNR. Statistical methods applied included analysis of variance with Tukey honestly significant difference test for pair wise comparisons. The a priori alpha was set at P < or = 0.05. RESULTS: SNR decreased with increased duration and intensity of pre-scanning light exposure. Lower X-ray exposures resulted in decreased signal resulting in reduced SNR, and increased the need to reduce ambient lighting. No statistically significant differences were found comparing ScanX and DenOptix digital imaging systems in terms of SNR. CONCLUSION: Reduced ambient lighting is preferred for handling IPs prior to processing in the laser scanner.

Effect of beam energy and filtration on the signal-to-noise ratio of the Dexis intraoral X-ray detector.

OBJECTIVE: To evaluate the signal-to-noise ratio (SNR) of the Dexis charge-coupled device (CCD) intraoral X-ray detector, with special reference to the influence of beam energy and filtration. MATERIAL AND METHODS: Digital radiographic images were made of a nine-step dental aluminium step wedge using a Dexis intraoral detector. The X-ray generator was a GE 1000 operating at 10 mA with 2.7 mm aluminium filtration. The peak tube voltage settings applied were 50 kVp, 60 kVp, 70 kVp, 80 kVp and 90 kVp. Various exposure times were used at each beam energy and the exposures (in micro C kg(-1)) were determined in each case using a 3 cl beryllium-windowed ionization chamber. SNR was defined using the surrogate measure of mean pixel value (surrogate for signal) divided by the standard deviation of the pixel value (surrogate for noise). SNRs were measured at separate regions of interest (ROIs) at the centre and at both sides of the detector for each aluminium step as well as without the step. RESULTS: For beam energies of 50 kVp and 60 kVp, the estimated SNR improved both with increased exposure and with increased filtration (thickness of the aluminium step), and image saturation did not occur within the exposure time range permitted by the Dexis software. At 70 kVp and above, the SNR was optimized in the middle of the exposure range: 4 micro C kg(-1) with 290:1 at the ninth step (13.5 mm Al) for 70 kVp; 3.5 micro C kg(-1) with 240:1 at the ninth step (13.5 mm Al) for 80 kVp; 3.5 micro C kg(-1) with 160:1 at the ninth step (13.5 mm Al) for 90 kVp. Saturation did occur at these beam energies within the exposure time range permitted by the Dexis software. CONCLUSION: For the Dexis intraoral radiographic imaging system, estimated SNR improved both with higher filtration and with lower kVp. The Dexis detector was capable of generating acceptable images of the step wedge at a wide range of kVp settings.

Array geometry for assessment of mandibular implant position using tuned aperture computed tomography (TACT).

OBJECTIVE: To evaluate observer faciolingual depth and vertical depth reading errors when using various X-ray beam array geometries to make basis images for tomosynthetic reconstruction using tuned aperture computed tomography (TACT). MATERIALS AND METHODS: Tissue-equivalent models were constructed to replicate the position of dental implants in relation to simulated mandibular canals. X-ray beam geometries used to acquire the basis images for TACT(TM) integration included horizontal linear, vertical linear, and symmetric and asymmetric conical arrays. Twenty-one dentists trained in the use of TACT acted independently as observers. Tasks included: (1) determination of the relative position of the implant in relation to the simulated canal; and (2) measurement of the vertical depth and faciolingual (lateral) depth dimensions between these two structures. As the study did not involve repeated measures (only one measure was obtained from each observer on each of the two dependent variables), data for faciolingual depth and vertical depth reading errors were analysed using a one-way analysis of variance (ANOVA) with Tukey's honestly significant different (HSD) procedure. RESULTS: Errors in determining the relative position of the implant to the simulated canal were most frequent when the linear horizontal projection geometry was employed for producing basis images (57% error for model #2 where the implant was lingually placed). The mean measurement errors for TACT images constructed using the various different projection arrays depended both on the structural relationship of anatomic features and the employed beam array geometry. CONCLUSION: Conical beam arrays are preferred over linear beam arrays for constructing basis images used with TACT for the purpose of correlating the position of a mandibular dental implant in relation to the mandibular canal. They more consistently allowed the observers to establish a measurement of the faciolingual relationship of the implant to the canal. For vertical depth measurement of the relationship of a mandibular dental implant to the mandibular canal, TACT does not appear to have any advantage over individual simple transmission radiographic images.

Fundamentals of image acquisition and processing in the digital era.

OBJECTIVES: To review the historic context for digital imaging in dentistry and to outline the fundamental issues related to digital imaging modalities. CONTEXT: Digital dental X-ray images can be achieved by scanning analog film radiographs (secondary capture), with photostimulable phosphors, or using solid-state detectors (e.g. charge-coupled device and complementary metal oxide semiconductor). There are four characteristics that are basic to all digital image detectors; namely, size of active area, signal-to-noise ratio, contrast resolution and the spatial resolution. To perceive structure in a radiographic image, there needs to be sufficient difference between contrasting densities. This primarily depends on the differences in the attenuation of the X-ray beam by adjacent tissues. It is also depends on the signal received; therefore, contrast tends to increase with increased exposure. Given adequate signal and sufficient differences in radiodensity, contrast will be sufficient to differentiate between adjacent structures, irrespective of the recording modality and processing used. Where contrast is not sufficient, digital images can sometimes be post-processed to disclose details that would otherwise go undetected. For example, cephalogram isodensity mapping can improve soft tissue detail. CONCLUSIONS: It is concluded that it could be a further decade or two before three-dimensional digital imaging systems entirely replace two-dimensional analog films. Such systems need not only to produce prettier images, but also to provide a demonstrable evidence-based higher standard of care at a cost that is not economically prohibitive for the practitioner or society, and which allows efficient and effective workflow within the business of dental practice.

Image file interoperability for data protection, communication and trans-system connectivity.

DICOM (Digital Imaging and Communication in Medicine) is a set of international imaging standards developed for medicine and extended to incorporate other professions. These standards encompass primary digital and secondary capture images made for dental diagnostic procedures. The standards provide a basis of interoperability for digital system outputs, providing portability and reducing the danger of obsolescence that would render valuable diagnostic information impossible to display. The American Dental Association, through the activities of its Working Group 12.1, is promoting interoperability within DICOM as the industry standard for digital imaging in dentistry.

Outcomes of digital X-ray mini-panel examinations for patients having mental retardation and developmental disability.

OBJECTIVES: Severely and profoundly mentally retarded and developmentally disabled (MR/DD) patients are unable to communicate disease symptoms, and radiographic examinations are often difficult to perform on non-sedated patients. This clinical trial evaluated the impact on dental treatment planning of radiographic mini-panels for MR/DD patients. METHODS: With Institutional Review Board approval and informed consent of the legal guardian of each patient, a digital series of six periapical radiographs was achieved without sedation on 72 MR/DD inpatients (the survey was attempted on 74 patients). RESULTS: The average number of teeth included in each mini-panel was 20.4 compared with 22.2 teeth found clinically and 22.7 teeth determined combining both clinical and radiographic findings. Individual mini-panel images were judged technically excellent in 65% of cases, diagnostically satisfactory in 26% of cases and suboptimal in 9%. The radiographic panels were judged to affect treatment planning for more than 60% of the patients included in the trial. In 32% the detected condition was one or more periapical radiolucency. Several radiographic findings indicated potentially painful conditions that perhaps explained patient actions previously attributed to behavioural problems. Potential sources of dental pain and sepsis were treated by endodontic therapy or dental extractions on a case-by-case basis with or without general anesthesia. The trial also demonstrated a need that has translated into increased state allocations for dental treatment of MR/DD patients resident in the Commonwealth of Kentucky. CONCLUSIONS: Dental inspections of MR/DD patients are incomplete if radiographs are excluded. Whilst the mini-panel approach could be considered incomplete, it is better than no radiographs at all. 91% of images were excellent to satisfactory in diagnostic quality and a majority of patients' treatments were modified because of the radiographic information.

Comparison of complementary metal oxide semiconductor and charge-coupled device intraoral X-ray detectors using subjective image quality.

OBJECTIVE: To compare the subjective image quality of the newer generation Schick CDR detector employing complementary metal oxide semiconductor (CMOS) technology with images using the earlier generation charge-coupled device (CCD) Schick CDR detector. METHODS: All radiographic images were made using the same formalin-fixed adult cadaver maxilla with surrounding natural soft tissues in place. The X-ray generator used was a Villa Sistemi Medicali Diamatic srl AP/Explor X operated at 70 kVp and 8 mA. The source-to-detector distance was set at 38 cm and an optical bench was used to ensure reproducible beam geometry. A range of exposures was applied for both detectors. A panel of nine dentists independently observed and evaluated images made at each exposure. For both detectors, the three images ranked highest were randomized for re-evaluation in panels of six images. Each image was repeated randomly a total of 10 times. Features chosen as observation points were: (1) proximal dental caries; (2) gingival soft tissues; (3) cortical bone; (4) root canal space; (5) root apices; (6) periodontal ligament space; and (7) endodontic instrument tip clarity. Comparisons were made by use of odds ratio analysis applying a 95% confidence level. Interrater and intrarater reliabilities were computed to assess consistency in observer ratings. RESULTS: The CMOS sensor was rated as outperforming its CCD predecessor for depiction of cortical bone and root apices; the CCD detector was only rated superior for depiction of root canal space. No significant difference was found between the two detectors in perceived depiction of proximal dental caries, gingival soft tissues, periodontal ligament space or endodontic instruments. Combining rating scores from each of the tasks, CMOS and CCD detectors had a similar proportion of image ratings of excellent, acceptable and poor. CONCLUSIONS: Regarding subjective image quality, the Schick CMOS and CCD detectors were perceived to produce radiographic images of similar overall quality.

A sequential approach to radiological interpretation.

A case of large glandular odontogenic cyst of the mandible is presented in which the panoramic radiograph also demonstrated a soft tissue lesion consistent with carotid aneurysm. CT confirmed the bucco-lingual extent of the mandibular lesion and the presence of a soft tissue lesion consistent with an aneurysm of the internal carotid artery. CT angiography, MR angiography and US were used to rule out a carotid artery aneurysm prior to surgery of the mandibular lesion.

A comparison of image characteristics and convenience in panoramic radiography using charge-coupled device, storage phosphor, and film receptors.

This study compared the image layer characteristics, dose requirements, and convenience in use of panoramic radiography using each of four different image receptors including traditional indirect exposure x-ray film, a storage phosphor system, and two solid-state sensors. The OP 100 D (Instrumentarium Imaging, Tuusula, Finland) charge-coupled device (CCD) sensor provided an instant image with a wide focal trough, making patient positioning error unlikely, but at the same time required a patient dose higher than that used with film. While the DigiPan (Trex/Trophy, Marne-la-Vallée, France) CCD significantly reduced the patient dose to radiation and also provided an instant image, the focal trough was narrower making patient positioning error more likely. The storage phosphor system provided high resolution and a reasonable focal trough width, but the procedure took longer than traditional film radiography and did not provide a dose saving.