A New Filter Approach Based on Effective Ranges for Classification of Gene Expression Data

Over the years, many studies have been carried out to reduce and eliminate the effects of diseases on human health. Gene expression data sets play a critical role in diagnosing and treating diseases. These data sets consist of thousands of genes and a small number of sample sizes. This situation creates the curse of dimensionality and it becomes problematic to analyze such data sets. One of the most effective strategies to solve this problem is feature selection methods. Feature selection is a preprocessing step to improve classification performance by selecting the most relevant and informative features while increasing the accuracy of classification. In this article, we propose a new statistically based filter method for the feature selection approach named Effective Range-based Feature Selection Algorithm (FSAER). As an extension of the previous Effective Range based Gene Selection (ERGS) and Improved Feature Selection based on Effective Range (IFSER) algorithms, our novel method includes the advantages of both methods while taking into account the disjoint area. To illustrate the efficacy of the proposed algorithm, the experiments have been conducted on six benchmark gene expression data sets. The results of the FSAER and the other filter methods have been compared in terms of classification accuracies to demonstrate the effectiveness of the proposed method. For classification methods, support vector machines, naive Bayes classifier, and k-nearest neighbor algorithms have been used.

Does the horizontal condylar angle have a relationship with temporomandibular joint osteoarthritis and condylar position? A cone-beam computed tomography study

BACKGROUND

To evaluate the relationship between the horizontal condylar angle (HCA), temporomandibular joint osteoarthritis (TMJ OA), and condylar position on cone-beam computed tomography (CBCT) images.

MATERIALS AND METHODS

Based on TMJ OA, joints were classified as affected and the unaffected. According to the OA condition of their joints, three groups of patients were formed: control group (n = 159, 41.1%), unilateral group (n = 121, 31.3%), and bilateral group (n = 107, 27.6%). In total, the HCAs of 774 TMJs of 387 patients were measured and their condylar positions were determined as concentric (n = 184, 23.8%), posterior (n = 338, 43.7%), and anterior (n = 252, 32.5%).

RESULTS

The mean HCA of the bilateral group (22.7° ± 7.6°) was greater than those in both the control (19.5° ± 6.4°) and the unilateral (20.5° ± 6.5°) groups (p < 0.05). However, the difference was not statistically significant between the control and unilateral group (p > 0.05). In total patients, unlike the unilateral group, the affected joints had a greater mean HCA than the unaffected joints (p < 0.05). The mean HCAs of the joints according to the condylar position were as concentric: 20.6° ± 6.7°, posterior: 21.1° ± 7.8°, and anterior: 20.2° ± 7.9° (p > 0.05).

CONCLUSIONS

While the HCA increased in the presence of TMJ OA, no relationship was found between HCA and three different condylar positions.

Idiopathic coronal resorption in impacted permanent teeth and its relationship with age: radiologic study

Purpose

The purpose of this study was to evaluate the relationship between idiopathic coronal resorption and age in adult patients.

Materials and methods

3405 digital panoramic radiographs present in the archive of the radiology department belonging to 1584 males and 1821 females aged 25 and over were assessed by two oral and maxillofacial radiologists. The patients' age, gender, number of impacted teeth, number and position of teeth with idiopathic coronal resorption and the extent of coronal resorption were recorded on standard forms.

Results

A thousand and nine impacted teeth were observed in 622 patients (304 males and 318 females) with a mean age of 36,92 (±10,85). Idiopathic coronal resorption was present in 26 of the 622 patients with a frequency of 4.2%. One patient had two teeth with idiopathic coronal resorption; resulting in as 27 teeth and a frequency of 2.7% according to tooth number. There were 13 (50%) females and 13 (50%) males having idiopathic coronal resorption. There was no significant difference between genders. The presence of idiopathic coronal resorption increased with advanced age (v: 0,193, p<0.05). There was no statistically significant difference between the extent of the coronal resorption and age.

Conclusion

The presence of idiopathic coronal resorption increases with advancing age. Idiopathic coronal resorption is detected incidentally during radiographic examination. Thus, dentists should consider this situation and should perform periodically radiographic examination of impacted teeth.

Evaluation of the frequency of third molar agenesis according to different age groups

PURPOSE

Third molars (M3s) are the most common congenitally missing teeth. The aim of this study was to compare the frequency of M3 agenesis in two different age groups.

METHODS

This study examined the panoramic radiographic images of 1036 patients. Two groups, each consisting of 518 patients, were arranged based on age ranges. The patients aged 12 to 19 years were in the first group and those 20 years and older were in the second group. The frequency of M3 agenesis was examined in both age groups. The distribution of M3 agenesis by sex and jaw was also recorded, along with the number of M3s affected by agenesis. Chi-square tests were used to examine the relationships between categorical variables.

RESULTS

M3 agenesis was observed in 29.3% and 20.5% in the first and second groups, respectively; the difference was statistically significant (P < .01). It was more common in female (27.3%) than in male patients (21.4%), and in the maxilla (11.2%) than in the mandible (5.8%), and the differences were statistically significant (P < .05). It was mostly observed forthemaxilla right M3 (18) (30.9%) and in the single quadrant of the jaws (9.7%).

CONCLUSIONS

The frequency of M3 agenesis was more common in patients aged 12 to 19 years than in those aged 20 years and older. Additionally, M3 agenesis was more common in females and in the maxilla.

Turkish adaptation and implementation of the modified infection control questionnaire in intraoral digital imaging

Purpose

There are very few studies evaluating the knowledge of dentists about infection precautions in oral radiology. The aim of this study was to assess the psychometric properties of the Turkish version of the modified form of a developed questionnaire and to apply this questionnaire to Turkish dentists.

Materials and methods

The questionnaire was applied to a sample of 250 dentists for the scale development [200 for confirmatory factor analysis (CFA) and 50 for control] and 173 dentists for the implementation of the scale. The scale was applied to 200 dentists and construct validity was examined with CFA. For model fit; chi square to df ratio, RMSEA (Root Mean Square Error of Approximation), TLI (Tucker-Lewis Index), CFI (Comparative Fit Index), GFI (goodness of fit index), AGFI (adjusted goodness of fit index) and NFI (normed fit index) were obtained. Also, reliability analysis was applied and itemtotal correlations and Cronbach's alpha values were given. Adapted scale scores using a different sample of 173 dentists were compared according to demographic characteristics.

Results

CFA showed good fit statistics (X2/df=1.511, RMSEA=0.057, TLI=0.942, CFI=0.953, GFI=0.926, AGFI=0.900, NFI=0.928) for the scale. Item-total correlations were over 0.30 and Cronbach's alpha was calculated as 0.877. In addition, experienced dentists had higher scores in the dimension of personal hygiene (p<0.05).

Conclusion

The Turkish version of the modified infection control questionnaire in oral radiology showed adequate psychometric properties. This indicated that it could be a valid and reliable tool for the assessment of infection control in oral radiology among Turkish dentists.

Knowledge, behavior, and awareness of neonatologists and anesthesiologists about oral complications of intubation and protection methods

OBJECTIVES

This study aimed to assess awareness of anesthesiologists and neonatologists about oral complications occurring during and after the orotracheal intubation (OTI) in premature infants and their knowledge and behavior regarding protection methods from these complications in clinical practice.

METHODS

This study included 94 neonatologists and 137 anesthesiologist. The final version of the questionnaire included 15 items in three main parts: (i) personal information; (ii) awareness about oral complications occurring during and after the OTI in premature infants; (iii) knowledge and behavior regarding protection methods from these complications in clinical practice.

RESULTS

A total of 95.7% of neonatologists and 83.2% of anesthesiologists were aware of oral complications related to OTI. The most common complications the anesthesiologists encountered were oral, laryngeal, or pharyngeal region injuries (60.7%) and palatal groove (52.2%) for the neonatologists. The most preferred method for stabilization of the orotracheal intubation tube (OTT) was bonding to the perioral region with an adhesive tape (98.3%). The primary determining factor in the choice of OTT stabilization method was the ease of use (28.2%). A total of 23.8% of the participants were aware of the palatal stabilization device (PSD), whereas only 1.3% used it in their routine and 57.1% of them believed it can prevent complications.

CONCLUSIONS

The results showed that neonatologists were more aware of the OTI-related oral complications than anesthesiologists. The knowledge of the participants regarding prevention of these complications is insufficient. Study participants believe in the efficacy of PSD but do not use it in clinical practice for a number of reasons.

The Differences Between Preterm and Term Birth Affecting Initiation and Completion of Toilet Training Among Children: A Retrospective Case-Control Study

PURPOSE

This study seeks to investigate the possibility the existence of a difference in terms of start and end dates of toilet training between term and preterm children as well as the possible determining factors.

MATERIALS AND METHODS

This study was conducted as a 5-year retrospective case (children born preterm-(32 to <37 weeks) - and control (children born at term (>37 weeks + 1 day)) study. The data were collected with a form consisted of questions about demographic data (12 questions) and toilet traning features (10 questions) through face-to-face interviews with the mothers. A chi-square test and logistic regression analysis were conducted to examine the data. Odds ratio was used as a measure of the relation between levels of the dependent variable. p< .01 and p< .05 values were assumed to be statistically significant.

RESULTS

The study examined a total of 133 children including 59 preterm children and 74 children born at term including 60 (45.1%) boys and 73 (54.9%) girls. The possibility of starting toilet training at or before 24 months was found to be 6.4 times greater in full-term children than preterm children (OR=6.493). The logistic regression analysis, which aimed at identifying any variables that might affect end date of toilet training, found that despite the tendency to consider preterm   birth as a factor prolonging the duration of toilet training, the difference was not found to be statistically significant (p= .07).

CONCLUSION

This study compared full-term and preterm children in terms of start and end dates of toilet training and found that preterm children start toilet training later than full-term children. Based on the results of the study, it is possible to say that preterm birth, gender and birth order affect start date of toilet training. However there is no difference between term and preterm babies on the end date of toilet training.

A pilot study of the effects of a vacuum sealing barrier method for photostimulable phosphor plates regarding plate damage and prevention of microbiologic cross-contamination

OBJECTIVE

The aim of this study was to evaluate the effectiveness of a new sealing method for preventing cross-contamination of photostimulable phosphor (PSP) plates.

STUDY DESIGN

Twelve new PSP plates were divided into 3 groups (PSP-a, PSP-b, and PSP- c) and placed in 3 different barriers (2 different brands of envelopes and a vacuum sealing method). All plates were exposed to X-rays with an aluminum step wedge, and the images were evaluated for the presence of any artifacts. After radiography, the PSP plates were removed from the barriers. The barriers and the PSP plates were disinfected and culture performed to assess any microorganism burden. Subsequently, the PSP plates were coated again with all barriers. The barriers were then contaminated and microbiologic specimens were collected. Subsequently, the barriers were wiped with alcohol. The PSP plates were removed, and microbiologic specimens were obtained.

RESULTS

No artifacts were recorded on the radiographic images on the sensors in any group. Microorganisms were detected on the PSP plates placed in envelopes. No colonization of microorganisms was detected on the vacuum sealed PSP plates.

CONCLUSIONS

The new vacuum-sealing method may be useful in preventing cross-contamination of PSP plates during radiographic procedures.

DIAGNOSTIC ACCURACY OF CONE-BEAM COMPUTED TOMOGRAPHY IN DETECTING SECONDARY CARIES UNDER COMPOSITE FILLINGS: AN IN VITRO STUDY

Purpose:

The aim of this in vitro study was to assess the diagnostic performance of cone-beam computed tomography (CBCT) in the detection of secondary carious lesions under composite resin fillings applied to different types of cavities.

Materials and Methods:

Occlusal cavities (O) (n=18), occlusal cavities with mesial or distal component (MO/DO) (n=30), and mesial–occlusal–distal cavities (MOD) (n=30) were prepared in seventy eight extracted human posterior teeth. In half of the cavities in each group, artificial secondary caries lesions were simulated. All cavities were restored by using composite resin. All specimens were embedded in silicone and they were positioned to have approximal contacts. CBCT imaging was done and data were evaluated two times with two week interval by two observers, using a five-point confidence scale. Intra- and inter-observer agreements were calculated with Kappa statistics (κ). The area under (Az) the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic accuracy.

Results:

Intra- (κ =0.89) and inter-observer (κ = 0.79) agreements were found to be excellent. Az values were highest for the O restorations which is followed by the MOD and DO/MO restorations. Az values for MOD and DO/MO restorations were very low and no statistically significant difference was found. Sensitivity for DO/MO restorations and specificity for MOD restorations were found to be the lowest values.

Conclusion:

Diagnostic performance of CBCT was higher in O composite restorations than MOD and DO/MO restorations for secondary caries detection. The use of alternative imaging methods rather than CBCT may be useful for evaluating secondary caries under composite MOD and DO/MO restorations.

The comparison of subjective image quality in conventional and digital panoramic radiography

OBJECTIVE

The purpose of this study was to compare the subjective image quality of (1) regular intensifying screens with medium intensifying screens, (2) regular intensifying screens with digital radiography, and (3) medium intensifying screens with digital radiography for panoramic radiographs.

MATERIALS AND METHODS

Forty-five patients participated and a total of 90 radiographs were obtained in the study. The patients were divided into three groups (regular-medium intensifying screen, regular intensifying screen-digital radiography, and medium intensifying screen-digital radiography) that consisted of 15 people each. All radiographs were assessed by three oral radiologists independently. The observers evaluated the images using a 3-point scale (1=well visible, 0=partly visible, -1=not or hardly visible) for anatomical structures and pathological findings that are commonly found on panoramic radiographs. Subjective image quality of the groups and comparison of the observers were assessed by using non parametric Kruskal Wallis and Mann-Whitney U tests.

RESULTS

For all groups and observers, no statistically significant difference (p>0.05) was found for both anatomical structures and pathologies and between anatomical structures and pathologies according to the Mann Whitney U test. In comparison with observers, no statistically significant difference (p>0.05) was found for both anatomical structures and pathologies and between anatomical structures and pathologies for all groups according to the Kruskal Wallis test.

CONCLUSION

The subjective image quality of medium and regular intensifying screens and conventional and digital panoramic radiographs were found statistically equal in this study.

Clinical evaluation of dose reduction on image quality of panoramic radiographs

AIM

The purpose of this study was to evaluate the effect of tube current reduction on image quality using medium and regular intensifying screens as well as a digital system for panoramic radiography.

METHODS AND MATERIALS

A total of 150 panoramic images of 75 patients were obtained in the study. The initial images were taken at standard exposure settings, and secondary images were exposed with the tube current reduced at different rates.

RESULTS

There was no statistically significant difference (p>0.05) between the two exposures for Group 3 (the rate of dose reduction 25%) while a statistically significant difference (p<0.05) was found in Group 4 (the rate of dose reduction 50%) using medium intensifying screens for all observers. No statistically significant difference was found between the two exposures on digital panoramic images.

CONCLUSION

According to the results of this study a dose reduction of 25% was achieved for medium intensifying screens and for digital panoramic images without any loss of image quality.

CLINICAL SIGNIFICANCE

A substantial reduction in radiation exposure can be achieved in conventional panoramic radiography using a medium intensifying screen and in digital panoramic radiography without any loss of image quality needed for radiological evaluation of anatomical structures and pathological conditions.

Film tomography compared with film and digital bitewing radiography for proximal caries detection

OBJECTIVES

The purpose of this study was to evaluate the efficiency of conventional tomography for proximal caries detection compared with conventional bitewing and digital intraoral radiography.

METHODS

In this study, 48 extracted human posterior permanent teeth were used. Conventional bitewing radiographs, digital intraoral radiographs and conventional tomograms were obtained of the teeth. The presence or absence of caries was scored according to a five-point scale by two oral and maxillofacial radiologists. True caries depth was determined by histological examination. The diagnostic accuracy of each radiographic system was assessed by means of receiver operating characteristic (ROC) curve analysis. The mean of areas under the ROC curve (A(z)) was analysed by pairwise comparison of ROC curve. The interobserver agreement was evaluated using a t-test.

RESULTS

The statistical analysis of A(z) scores has shown no significant difference for three imaging modalities (P>0.05). There was no statistically significant difference between interobserver agreement (P>0.05).

CONCLUSIONS

This study has demonstrated that the diagnostic accuracy of conventional tomograms is comparable to that of conventional bitewing and digital intraoral radiographs for proximal caries detection.

In vitro comparison of four different dental X-ray films and direct digital radiography for proximal caries detection

This study investigated the efficiency of different speeds of conventional intraoral films and a direct digital system for proximal caries detection. In this study, 48 extracted human posterior permanent teeth were used. Conventional bitewing radiographs and direct digital radiographs were obtained from the teeth. Three observers independently assessed 96 proximal surfaces, each observer had 10 years of experience. The presence or absence of caries was scored according to a five-point scale. True caries depth was determined by histological examination. The diagnostic accuracy of each radiographic system was assessed by means of a receiver operating characteristic (ROC) curve analysis. The mean of areas under the ROC curve (Az) was analyzed by pairwise comparison of ROC curve. The interobserver agreement was evaluated by using ANOVA analysis. The statistical analysis of Az scores exhibited no significant difference for the five imaging modalities (p > 0.05). There was no statistically significant difference between interobserver agreements (p > 0.05). The results of this study showed that the diagnostic performance of E- and F-speed films and direct digital radiography are similar for proximal caries detection.