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Biomedical subjects

G Lomçali

Publications and source records attributed to G Lomçali.

7 recordsLinked to original sources
PubMed2005

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.

Absorptiometry, Photon↗
PubMed1998

Densitometric evaluation of four radiographic processing solutions.

OBJECTIVE: To determine the performance of different processing solutions using an automatic processor for dental radiography. STUDY DESIGN: One brand of dental X-ray film (Minimax, Chicago, IL, USA) was developed in an automatic processor using four different brands of processing solution: Megasan (MGS, Megasan, Ankara, Turkey), (HAC, Ankara, Turkey), Fuji (Fuji Medical, Hacettepe Cedex, France) and RP X-Omat (Eastman Kodak, Rochester, NY, USA) at a range of temperatures. Performance was evaluated with respect to base plug fog density, relative speed and contrast. RESULTS: All solutions produced acceptable base plus fog values. MGS produced significantly greater densities (P < 0.05) than the other three solutions. Contrast obtained with Kodak and Fuji solutions was less than with MGS and HAC. Developing temperature recommended by the manufacturer of the processor were found to be higher than that needed to achieve a clinically acceptable film. CONCLUSIONS: Depending on the processor and processing solutions used, exposure time and processing temperature can be modified while maintaining image quality. The cheapest processing solution (MGS) gave the same results as the more expensive.

Absorptiometry, Photon↗
PubMed1996

Scanning electron microscopic observations of apical root surfaces of teeth with apical periodontitis.

The aim of this study was to observe apical root surfaces of teeth with chronic periapical lesions. Five premolars and three molars with radiographically demonstrable periapical lesions were extracted and fixed in 2.5% phosphate-buffered glutaraldehyde solution for 9 days. The apical 3-mm portion of 17 roots was removed and prepared for scanning electron microscope. Lacunar resorption zones were frequently observed on the root surfaces. Bacteria and yeast cells were detected in some of the lacunae. Periapical bacterial plaque with a smooth structure was present mostly around the main apical foramen. Cementum-like tissue deposits indicative of repair were seen adjacent to some resorption areas. Clastic cells tightly attached to crater-like depressions with finger-like projections were observed laterally on the specimens. Current research should be focused on new procedures to eliminate extraradicular microrganisms and periapical bacterial plaque in persistent periapical infections.

Chronic Disease↗
PubMed1994

Talon cusp: report of five cases.

Talon cusp is a rare phenomenon found on the lingual surfaces of anterior teeth. Five cases of talon cusp that were observed during routine clinical examination are described.

Adolescent↗