Radiopacity of Posterior Restorative Materials: A Comparative In Vitro Study.

BACKGROUND: The objective was to investigate the radiopacity of 11 commercial posterior restorative materials by establishing their mean gray values (MGVs) and comparing them with dental hard tissues. METHODS AND MATERIALS: Five-disc specimens were prepared for each of the following materials: Cerasmart 270 CAD/CAM block A3LT (CS), Amalgam (A), Ketac Molar A3 (KM), Cention-N A2 (CN), G-aenial Universal Flo AO2 (GO2) and A2 (G2), Ever-X Flow Dentine (EXD) and Bulk (EXB) shades, Equia Forte HT Fil A2 (EF2) and A3 (EF3), and Equia Fil A3 (E3). Freshly extracted maxillary premolar teeth were used as a control. The MGVs of specimens and a 10-step aluminum stepwedge (Al) were measured with Adobe Photoshop. ANOVA and Dunnett T3 tests were used to assess the significance of the differences (α=0.05). RESULTS: Statistically significant differences were revealed between some of the groups. Amalgam had the highest radiopacity. The radiopacity of dentin and CS were close to that of 1 mm Al. G2, KM, GO2, EXB, and EXD showed higher mean radiopacity than dentin. Enamel had a radiopacity equivalent to 2 mm Al. CN, EF2, and E3 had higher mean radiopacity than enamel. CONCLUSIONS: All materials met the ISO requirements. Alkasite and reinforced glass ionomer restoratives demonstrated higher mean radiopacity than the posterior flowable composites. Material shades did not affect the radiopacity.

Improving Oral Cancer Outcomes with Imaging and Artificial Intelligence.

Early diagnosis is the most important determinant of oral and oropharyngeal squamous cell carcinoma (OPSCC) outcomes, yet most of these cancers are detected late, when outcomes are poor. Typically, nonspecialists such as dentists screen for oral cancer risk, and then they refer high-risk patients to specialists for biopsy-based diagnosis. Because the clinical appearance of oral mucosal lesions is not an adequate indicator of their diagnosis, status, or risk level, this initial triage process is inaccurate, with poor sensitivity and specificity. The objective of this study is to provide an overview of emerging optical imaging modalities and novel artificial intelligence-based approaches, as well as to evaluate their individual and combined utility and implications for improving oral cancer detection and outcomes. The principles of image-based approaches to detecting oral cancer are placed within the context of clinical needs and parameters. A brief overview of artificial intelligence approaches and algorithms is presented, and studies that use these 2 approaches singly and together are cited and evaluated. In recent years, a range of novel imaging modalities has been investigated for their applicability to improving oral cancer outcomes, yet none of them have found widespread adoption or significantly affected clinical practice or outcomes. Artificial intelligence approaches are beginning to have considerable impact in improving diagnostic accuracy in some fields of medicine, but to date, only limited studies apply to oral cancer. These studies demonstrate that artificial intelligence approaches combined with imaging can have considerable impact on oral cancer outcomes, with applications ranging from low-cost screening with smartphone-based probes to algorithm-guided detection of oral lesion heterogeneity and margins using optical coherence tomography. Combined imaging and artificial intelligence approaches can improve oral cancer outcomes through improved detection and diagnosis.

Regenerative Endodontic Therapy with Platelet Rich Fibrin: Case Series.

Regenerative endodontic therapy (RET) provides a novel treatment modality for the immature teeth with pulp necrosis. The aim of this case series was to evaluate RET of immature permanent teeth using platelet rich fibrin (PRF) at 36-month follow-up periods. In the present case series, three immature maxillary incisors diagnosed with pulp necrosis and apical periodontitis were treated with RET. The root canals were irrigated with 1.5% sodium hypochlorite (NaOCl) and medicated with triple antibiotic paste(TAP). At the second visit, TAP was removed and root canals were conditioned with 17% EDTA. PRF was used as a scaffold. MTA was placed over PRF and the teeth were restored with composite resin. Periapical radiographs and cone beam computerized tomography(CBCT) were used to evaluate the healing. At the end of the 36-month follow-up periods, there was no response to pulp sensibility tests with cold and electric pulp tester, but all teeth showed decreased periapical lesions or evidence of healing.

Treatment of immature teeth with nonvital pulps in adults: a prospective comparative clinical study comparing MTA with Ca(OH)2.

AIM: To evaluate and compare the influence of various predictors on outcomes of apexification using either mineral trioxide aggregate (MTA) or calcium hydroxide (CH) in permanent immature anterior teeth with necrotic pulps and periapical lesions of adults. METHODOLOGY: Ninety immature teeth with necrotic pulps and periapical lesions on adult patients (aged 18-40 years) were treated with MTA (45 teeth) or CH (45 teeth) between 2015 and 2018. Patients of both groups were recalled for follow-up examinations after the first intervention at 1,3,6 and 12 months for the first year, every 6 months for the second year and every year thereafter until the end of the study (median 32.3 months). The treatment outcome based on clinical and radiographic criteria was assessed by calibrated examiners and dichotomized as 'healed+healing' or 'not healed'. The age, gender, stage of root development, preoperative signs and symptoms of apical periodontitis and size of periapical lesion were recorded. The cumulative success proportion and mean time were analysed with the Kaplan-Meier test. The generalized logrank statistic was used to describe prognostic clinical variables. Fisher's exact test was applied for the evaluation of the healing rates. RESULTS: Thirty-nine of the 45 teeth treated with MTA were available for recall. Of these, 29 teeth (74%) revealed calcific apical barrier formation with complete resolution of periapical lesions, 7 teeth (18%) were healing, and 3 teeth (8%) had persistent disease. Thirty-four of the 45 teeth in the CH group were available for recall. Of these, 27 teeth (79%) had complete healing of periapical lesions and had calcific barrier formation, 4 teeth (12%) were healing, and the remaining 3 teeth (9%) had not healed. The survival rate of teeth treated with MTA was similar to the survival rates observed in teeth treated with CH (90% and 91%, respectively, P > 0.05). The generalized logrank statistic revealed that the cumulative success rate of both materials was not significantly different (P > 0.05). None of the tested predictors had an influence on the treatment outcomes of teeth in both groups (P > 0.05). CONCLUSIONS: Apexification with both MTA and CH was associated with similar treatment outcomes. MTA may be proposed as a material for apexification treatment in immature teeth of adult patients due to the shorter treatment time associated with its use.

Regenerative endodontic treatment of perforated internal root resorption: a case report.

AIM: To present the regenerative endodontic treatment procedure of a perforated internal root resorption case and its clinical and radiographic findings after 2 years. SUMMARY: A 14-year-old female patient was referred complaining of moderate pain associated with her maxillary left lateral incisor. After radiographic examination, a perforated internal resorption lesion in the middle third of tooth 22 was detected. Under local anaesthesia and rubber dam isolation, an access cavity was prepared and the root canal was shaped using K-files under copious irrigation with 1% NaOCl, 17% EDTA and distilled water. At the end of the first and second appointments, calcium hydroxide (CH) paste was placed in the root canal using a lentulo. After 3 months, the CH paste was removed using 1% NaOCl and 17% EDTA solutions and bleeding in the root canal was achieved by placing a size 20 K-file into the periapical tissues. Mineral trioxide aggregate was then placed over the blood clot. The access cavity was restored using glass-ionomer cement and resin composite. After 2 years, the tooth was asymptomatic and radiographic examination revealed hard tissue formation in the perforated resorption area and remodelling of the root surface. KEY LEARNING POINTS: Regenerative endodontic treatment procedures are an alternative approach to treat perforated internal root resorption lesions. Calcium hydroxide was effective as an intracanal medicament in regenerative endodontic treatment procedures.

Obstructive sleep apnoea and the need for its introduction into dental curricula.

Obstructive sleep apnoea (OSA) is a major health problem which causes blood oxygen desaturation that may initiate a cascade of events via inflammatory cytokines and adrenocorticotrophic hormone that may have impact upon quality of life and lead to potential life-threatening events. Even though OSA affects an increasing number of individuals, the role of dental practitioners in recognition, screening and management has not developed accordingly. The goal of this article was to provide updated information to dental practitioners on pathophysiology, consequences and treatment options of OSA with a focused discussion on oral appliance (OA) therapy, as this topic is not routinely included in current dental curricula of many dental schools. Additionally, we present a template dental curriculum for predoctoral and/or postdoctoral students in education regarding sleep disordered breathing.

Efficiency and apical extrusion of debris: a comparative ex vivo study of four retreatment techniques in severely curved root canals.

AIM: To compare the amount of apically extruded debris and of remaining filling material during the removal of root canal filling material using three rotary NiTi retreatment instruments or Hedström files. METHODOLOGY: Ninety-six severely curved human molars of both jaws were selected. The root canals were prepared to size X2 (tip size 25, .06 taper) using the ProTaper Next system (Dentsply Sirona, Ballaigues, Switzerland), filled with gutta-percha and AH Plus sealer (Dentsply De Trey, Konstanz, Germany) and then randomly divided into four experimental groups (n = 24 each) with two subgroups of maxillary and mandibular teeth each. An experimental model was used as a phantom head to simulate the upper and lower jaws. The root filling materials were removed with one of the following files using a crown-down preparation technique: I. Hedström files (H-files) (VDW, Munich, Germany), II. R-Endo (Micro-Mega, Besançon, France), III. Reciproc (VDW) and IV. ProTaper Universal Retreatment system (PTU-R) (Dentsply Maillefer). Apically extruded material was collected in vials, which were weighed with a microbalance (10-5  g) before and after the retreatment. The area of residual filling material in the coronal, middle and apical root level was assessed using digital analysis. These data were analysed statistically using ANOVA and the Kruskal-Wallis test. RESULTS: Reciproc was associated with significantly less extruded debris than the H-files (P = 0.009). No significant differences were detected amongst the four retreatment techniques concerning residual filling material (P = 0.082). The amount of extruded debris and areas of remaining filling material were not correlated (P = 0.901). Location of teeth in the maxilla or mandible had no impact on the amount of extruded debris within each instrument group (P = 0.609). However, when teeth were evaluated in general irrespective of the instruments, significantly more debris was extruded in the mandibular location (P < 0.001). CONCLUSIONS: All retreatment systems were associated with apical extrusion of debris, but H-files extruded significantly more material than Reciproc. Remnants of filling material were observed in all samples with no significant differences between the four techniques.

Marginal bone loss of two implant systems with three different superstructure materials: a randomised clinical trial.

Marginal bone level is a criterion for implant success. The aetiological factors of bone loss have not been clarified. The aim of this study was to evaluate the influence of implant systems and prosthetic materials on the marginal bone loss. Twenty-three patients participated; two implant systems and three superstructure materials were used in this study. Twenty-two of the implants were restored with porcelain fused to base metal alloy (BMA), 25 with porcelain fused to noble metal alloy (NMA) and 20 with zirconium oxide-based ceramics. Radiographs were taken at baseline and 3, 6 and 12 months after loading. Crestal bone-level changes were assessed with digital subtraction radiographs. The effects of superstructure materials and implants were evaluated with one-way anova and independent samples t-test, respectively (α = 0·05). The mean crestal bone loss was found 0·483 mm in 3 months, 0·622 mm in 6 months and 0·816 mm in 12 months. Prosthetic materials were found to have greater effect (ß = 0·575, P = 0·015) on crestal bone loss than implant systems (P > 0·05). The porcelain fused to BMA restorations showed higher crestal bone loss than NMA-based restorations (P = 0·003) at 3 months, (P = 0·038), at 6 months and (P = 0·00) at 12 months; however, crestal bone loss differences between NMA and zirconia were not significant (P = 0·629) at 3 months, (P = 0·974) at 6 months and (P = 1) at 12 months. Within the limitations of this study, our results revealed that rather than the implant systems, prosthetic materials seemed to have an effective role on crestal bone.

Efficacy of topical benzydamine hydrochloride gel on oral mucosal ulcers: an in vivo animal study.

The aim of this study was to investigate the effect of benzydamine hydrochloride bioadhesive gel on healing of oral mucosal ulceration in an animal model. For in vivo determination of the effects of the bioadhesive gel, 36 rabbits were separated into three groups: the first group was treated with the gel formulation without active agent, the second group with the gel formulation containing benzydamine, and the third group received no treatment. Clinical healing was established by measuring the area of the ulcer in each test group on days 3, 6, 9 and 12. Histological healing was determined on the same days. Benzydamine containing gel applications resulted in a decrease in the ulcer area in 12 days (p=0.000). Histological evaluation showed that the benzydamine group had a higher mean histological score than the base and the control groups during the whole test period, and the difference between the benzydamine group and the control group was significant (p=0.04). The bioadhesive gel formulation of benzydamine hydrochloride showed a statistically significant increased rate of mucosal repair in this experimental standard mucosal wound animal study. It is a candidate for the topical treatment of oral mucosal ulcerative lesions.

The utility of toluidine blue staining and brush cytology as adjuncts in clinical examination of suspicious oral mucosal lesions.

The objective of this study was to investigate the utility of toluidine blue and brush cytology in patients with clinically detected oral mucosal lesions. Clinical examination of 35 patients was completed before toluidine blue application, oral brush cytology and scalpel biopsy. Lesions were photographed before and after stain application; followed by brush cytology. All findings were compared with histopathologic results. Severe dysplasia and carcinoma-in-situ were determined as 'positive'; no dysplasia and mild to moderate dysplasia were defined as 'negative'. The sensitivity, specificity, positive and negative predictive values of clinical examination and toluidine blue were the same: 0.923, 0.433, 0.414, and 0.929, respectively. Those of brush cytology were 0.923, 0.517, 0.462, and 0.938. The concordance of all methods was 30% for benign and 61% for malignant lesions. Adjuncts identified 92% of carcinoma-in-situ and squamous cell carcinoma as confirmed by histopathology, in contrast to clinical findings alone in which 62% of these lesions were identified (p=0.046). In conclusion, adjunct diagnostic methods decreased the level of uncertainty for the diagnosis of oral malignancies and lichenoid dysplasias when applied as adjuncts to clinical examination.

Application of fractal analysis in hyperparathyroidism.

OBJECTIVES: Primary hyperparathyroidism (HPT) is a condition caused by an overproduction of parathormone, in excess of the amount required by the body. Its most common cause is a parathyroid gland adenoma and parathyroidectomy is currently the only curative treatment for primary HPT. We present a case history of a 65-year-old patient who was diagnosed with primary HPT after the recognition of dental problems. METHODS: Dental complaints of the patient alerted the dentists, and the patient was referred for further medical evaluation. In addition to his current medical status, his medical records including the biochemical parameters of bone metabolism recorded between 2001 and 2006 were reviewed. The panoramic films of the patient obtained between 1997 and 2008 were also assessed with the fractal analysis method. RESULTS: After consideration of the radiographical, biochemical and clinical evaluations of the patient, the final diagnosis was made as hyperparathyroid adenoma and surgical removal was scheduled. Soon after surgery, alkaline phosphatase, calcium and intact parathormone levels returned to normal. The fractal analysis value of the mandibular alveolar bone also increased. CONCLUSIONS: Dentoalveolar changes observed in HPT include alveolar bone demineralization. The fractal dimension (FD) analysis of the bone tissue has been introduced as an alternative method to investigate the quality of the alveolar bone. FD values of the patient showed osteoporotic bone characteristics between 1997 and 2006 until the date of parathyroidectomy. Mandibular bone FD analyses revealed a prominent development, which was also observed in dual energy X-ray absorptiometry values.

How many times can we use a phosphor plate? A preliminary study.

OBJECTIVES: Digital radiography has become a useful tool in daily dental practice due to the advances in imaging technologies. Charge coupled devices (CCDs) and photostimulable phosphor plates (PSPs) are currently in use for dental imaging; however, the longevity of PSPs in dental practice is not yet established. The aim of this study was to determine the service life of PSPs in a clinical setting. METHODS: Five unused PSPs were exposed with a conventional X-ray device and converted into digital images with Digora Optime (Soredex, Milwaukee, WI). These were recorded as the baseline images. Subsequent digital images of the plates were obtained after 20, 40, 60, 80, 100, 120, 140, 160, 180 and 200 exposures. All radiographic images were subtracted from the first digital image (baseline) and the mean grey values (MGVs) of the subtracted images were established using software. The data were grouped in 3 classes according to the number of exposures (20-80; 100-140; 160-200), and were analysed using variance analysis and chi(2) tests. RESULTS: The MGVs of the subtracted images varied between 126.25 and 127.59, and the difference was not significant among the groups (P = 0.11). However, the differences between the MGVs of the plates on each exposure settings were significantly different than those of the baseline image (P < 0.05). CONCLUSIONS: The findings of this study revealed that even though a slight deterioration occurred after the first exposure, each plate can be used up to 200 times. Further studies are required to reach a more concrete conclusion.

Turkish dentists' knowledge of head and neck cancer therapy-related complications: implications for the future.

UNLABELLED: The objective was to determine the level of knowledge about the orodental complications and their prevention/management in head and neck cancer therapy. MATERIALS AND METHODS: A 15-item questionnaire which was obtained from National Institute of Dental and Craniofacial Research that contained information about the orodental complications of the cancer therapy and the dentists' role to provide their treatment protocols. The pollsters visited 380 respondents, and the replies were analysed with stratified and logistic data analyses. Overall correct replies ranged from 14.71% to 99.5%. The participants knew the basic knowledge of the complications of cancer therapy; however, they failed to answer to the questions about the required clinical practices. The gender (P = 0.967), age (P = 0.977) and the duration of practice (P = 0.99) were not significant factors in providing correct replies. The rate of correct replies were not different among the test groups (P = 0.953). As a conclusion, rectification of dental curricula, organization of postgraduation courses, foundation of national councils for stimulation of the healthcare providers to incorporate knowledge into practice, to monitor the continuity of those programmes, and to award the dental practitioners who keep up the recent literature and optimal clinical practice are vital to improve the life quality of cancer patients.

Efficacy of a new software in eliminating the angulation errors in digital subtraction radiography.

OBJECTIVES: To evaluate the efficacy of a new software developed for digital subtraction radiography at tolerating the vertical and horizontal angulation changes between the X-ray source and object. METHODS: The right first molar of a preserved dry mandible was imaged with 0 degrees vertical and 0 degrees horizontal tube angulation. Then, the vertical angle was changed to +10 degrees, -10 degrees, +15 degrees and -15 degrees, and the same tooth was radiographed in each condition, accordingly. The same procedure was performed with 5 degrees horizontal angular modifications in both mesial and distal directions. All radiographs were automatically developed and were digitized with 600 dots per inch (dpi) spatial resolution. New software and Emago were used to subtract the images with angulation alterations from the original image, and a total of 20 subtracted images were obtained. Ten experienced specialists evaluated the images and rated the efficacy of the programs. Data were analysed statistically and alpha was accepted as 0.05. RESULTS: The total score of the new software was 190 and that of Emago was 117 for vertical angular alterations, whereas the scores were 51 and 21, respectively, for horizontal angular alterations. The differences between the overall scores of the softwares were statistically significant (P<0.05). Overall evaluation revealed that the new software was rated with higher scores for subtracted images obtained with both vertical and horizontal angular alterations. CONCLUSIONS: Both programs managed to tolerate vertical angulation alterations up to 10 degrees and horizontal angulation changes up to 5 degrees ; however, the new program performed better than Emago.

Facial subcutaneous calcinosis and mandibular resorption in systemic sclerosis: a case report.

Systemic sclerosis (SSc) is an autoimmune disease characterized by widespread fibrosis of subcutaneous connective tissue, causing serious complications with the involvement of other systems. Tight, firm skin is the main characteristic of SSc, causing extrinsic pressure and the obliteration of the vessels. This then leads to ischaemia and destruction of the underlying bone. This mechanism may also lead to bone resorption of the mandibular body as it affects other bones of the skeleton. To date, only two cases of reported calcinosis in the facial area have been observed. In this report, a rare case of SSc with both subcutaneous calcinosis and mandibular bone resorption is presented. The role of dental practitioners in the diagnosis of the disease with respect to the orofacial symptoms is also discussed.

Digital analysis of mouthrinses' staining characteristics on provisional acrylic resins.

Provisional restorations are expected to be both aestethically and physically durable during the preparation of permanent restorations. In this study, the staining properties of mouthrinses containing chlorhexidine gluconate, benzydamine hydrochloride and a hybrid mouthrinse were investigated on light and dark shades of a provisional acrylic resin. Totally 80 specimens were prepared and were photographed digitally to obtain the baseline L*, a*, b* values. Each sample was immersed in test solutions for 12 h which was equivalent time to 1 year of mouthrinse use, and the post-treatment images of the test materials were acquired. All L*, a*, b* values were analysed by a graphic software, and the total colour change (DeltaE*) of each specimen was calculated. Also the same colour analyses were performed on all test solutions to establish their colour parameters. Analysis of variance and Tukey's tests were used for statistical analyses and alpha was 0.05. All test solutions produced perceptible staining on the provisional material, with DeltaE values over 3.7. In both shades, hybrid rinse caused the highest staining (DeltaE=5.705), and was followed by chlorhexidine gluconate rinse, with DeltaE value of 4.120. The third highest staining was observed with benzydamine hydrochloride rinse (DeltaE=3.959), whereas the control caused the least staining (DeltaE=3.095). The lighter shade provisional material resulted with clinically observable staining even when immersed in distilled water; however, the dark shades showed clinically perceptible staining solely with the hybrid mouthrinse. In this study, the shade of the acrylic material was the determinator of the staining process.

Clinical efficacy of a new software developed for dental digital subtraction radiography.

OBJECTIVES: The aim of this study was to test and compare the efficacy of software developed recently for digital subtraction radiography (DSR) in vivo. METHODS: An algorithm performing both manual and automated image reconstructions and contrast correction was developed for the manipulation of radiographic images. Pre- and post-operative radiographic images of ten patients were obtained and the automated subtraction analyses were performed using four different softwares (new software, Emago, Photoshop 8.0 and Paintshop Pro 9). Ten experienced dental specialists evaluated the clinical efficacy of each program and scored the softwares by using visual analogue scales (VAS). The results were statistically analysed and alpha was set as 0.05. RESULTS: The newly developed algorithm received higher scores than the others (new software =67.89, Emago = 64.26, Paintshop Pro 9 = 33.41 and Photoshop 8.0 = 27.24, respectively). The clinical efficacies of the new software and Emago were not significantly different (P = 0.720); likewise, Photoshop 8.0 and Paintshop Pro 9 performed comparably (P = 0.295). CONCLUSIONS: Considering this study, the new software and Emago would be suggested for DSR in dental practice.

Comparison of digital and spectrophotometric measurements of colour shade guides.

Colour determination may be precisely performed with spectrophotometers, however this technique is time consuming and requires special devices. The aim of this study was to determine the correlation between the colour measurements performed on three shade guides of the same manufacturer, obtained with digital and spectrophotometric analyses. Sixty shade tabs of three shade guides were analysed to determine the L*, a*, b* values with a spectrophotometer. The same shade tabs were also imaged with a digital camera, and same colour parameters were determined on the digital images with the software. Three measurements for each shade tab were made with both methods. Statistical differences between the results of two methods were determined using anova (alpha = 0.05). Additionally, presence of any correlation between two methods within each guide was investigated by using correlation analysis. It was observed that the a* and b* values obtained by digital method were correlated with those of the spectrophotometer. Spectrophotometric analysis revealed no disparities among the L* measurements of the shade tabs of three shade guides (P > 0.05), but significant differences were observed between the L* values of the shade tabs with digital analysis method (P = 0.000). The digital method formed more subgroups than the spectrophotometer. For a* and b* values, both methods revealed significant differences among the shade tabs (P < 0.05). Additionally, both analyses revealed that colour characteristics of the first shade guide was different than the other two. The results obtained by digital method were correlated with those of the spectrophotometer, especially for a* and b* values.

The effects of incremental brightness and contrast adjustments on radiographic data: a quantitative study.

OBJECTIVES: To determine the border level of brightness and contrast changes in order to prevent the loss of originality of the quantitative data on digital dental radiographs. METHODS: After measuring the baseline mean grey values (MGVs) of a fixed region of interest on the alveolar bone and an aluminium step wedge, incremental brightness and contrast adjustments were performed on a digital periapical radiograph. The distribution of the data was analysed to investigate the significance of the changes on radiodensitometric data after incremental increase of brightness and contrast. RESULTS: The original MGVs were easily retrieved after brightness adjustments; however, the contrast increase led to more complicated density changes. The originality of the data was saved up to 50 units of contrast increase, but further than this limit, significant radiodensitometric changes occurred. CONCLUSIONS: Contrast adjustments should be performed cautiously when making quantitative analyses on the digital radiographs.

Application of a digital technique in evaluating the reliability of shade guides.

There appears to be a need for a reliable method for quantification of tooth colour and analysis of shade. Therefore, the primary objective of this study was to show the applicability of graphic software in colour analysis and secondly to investigate the reliability of commercial shade guides produced by the same manufacturer, using this digital technique. After confirming the reliability and reproducibility of the digital method by using self-assessed coloured images, three shade guides of the same manufacturer were photographed in daylight and in studio environments with a digital camera and saved in tagged image file format (TIFF) format. Colour analysis of each photograph was performed using the Adobe Photoshop 4.0 graphic program. Luminosity, and red, green, blue (L and RGB) values of each shade tab of each shade guide were measured and the data were subjected to statistical analysis using the repeated measure Anova test. The L and RGB values of the images taken in daylight differed significantly from those of the images taken in studio environment (P < 0.05). In both environments, the luminosity and red values of the shade tabs were significantly different from each other (P < 0.05). It was concluded that, when the environmental conditions were kept constant, the Adobe Photoshop 4.0 colour analysis program could be used to analyse the colour of images. On the other hand, the results revealed that the accuracy of shade tabs widely being used in colour matching should be readdressed.