DSR 3rd Issue

December, 2014

Issue

#03

DSR Switzerland, ISSN: 2296 - 1216

DENTAL STUDENTS’ RESEARCH JOURNAL

OFFICIAL RESEARCH PUBLICATION OF INTERNATIONAL ASSOCIATION OF DENTAL STUDENTS IN COLLABORATION WITH ASIA PACIFIC DENTAL STUDENTS’ ASSOCIATION

www.dsrjournal.org

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Scientific Content In vitro evaluation of dental enamel exposed to medicines used in pediatric cardiology

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Gokay Karapinar, Dr.Yegane Guven, Dr.Sule Batu, Dr.Ferda Dogan Istanbul University Turkey

Quality of Periapical Radiographs Taken

By Undergraduate Dental Students at Qassim University, Saudi Arabia Almogbel, Abdulmajeed Abdullah A (BDS) Dental Intern, College of Dentistry Qassim University, Alolayan, Abdulrahman Abdullah S (BDS) Dental Intern, College of Dentistry Qassim University Kingdom of Saudi Arabia

Mineral Composition of Enamel and Dentin of Intact Teeth in Patients with Thyroid Gland Pathology in Belgorod Region, Russia Peshkova Ella. Postgraduate student (BelSU) Federal State Autonomous Educational Institution of Higher Professional Education “Belgorod State National Research University” Russian Federation

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Publisher

from the editors

International Association of Dental Students

EDITORIAL Leadership Editor-in-chief - Pavel Scarlat (Italy/R. of Moldova) Scientific Associate Editor - Hossein Basir (USA/Iran) Communication Associate Editor - Esti Riyanda (Indonesia)

Dear Reader,

T

he year of 2014 comes to an end, and at the end of every year we should look behind to what was done but most importantly we should look in the future.

We have managed to publish two new issues of the journal, we have released our website and we continue to serve the research interests of the dental students at our best. The question is where the student research community worldwide heading, taking in consideration the difference of opportunities offered by the native Universities and the educational circumstances students find themselves.

Despite the scarse level of support towards student research in many educational environments in various places of the globe, the undergraduate/postgraduate student communities continue to grow and strive to rise towards their goals. We have noticed an increased tendency of participation at Lecture Research Contests, both internationally and on national levels, the number of such events growing as well. More and more student communities wake up and realise that they are strong enough in order to play an important role in the betterment of their own education, gathering together and holding such projects.

At the end of our thoughts, we would like to express our immense grattitude towards our colleague - Hossein Bassir, the Associate Scientific Editor of DSR. This Journal would have never been the same without his support and we owe him a lot for the very positive development of our publication. We wish him success in his career.

Thank you

Yours sincerely, Editorial Leadership

Cover Picture Credential: Dr. Pedram Pooryousefi, Netherlands

Advisory Honorary board Dr. Irina Dragan (USA) Dr. Jukka H. Meurman (Finland) Dr. Serena Sakoolnamarka (Thailand) Dr. Mauricio Gonzalez Balut (Mexico) Dr. Seow Liang Lin (Malaysia) Dr. Octavian Fagaras (Romania) Dr. Onur Kadioglu (USA) Dr. Latifa Berrezouga (Tunisia) Dr. Rudee Surarit (Thailand) Dr. Samuel Koo (USA) Dr. Joao Malta Barbosa (Portugal) Dr. Mohamed Salman (Saudi Arabia) Dr. Ionut Luchian (Romania) Dr. Derek Mahony (Australia) Dr. Hong Someth (Thailand) Dr. Latifa Berrezouga (Tunisia) Dr. Benny M. Soegiharto (Indonesia) Dr. Ansgar C. Cheng (Singapore) Dr. Alvin Wee (USA)

Editorial Board Jessica Zachar (Australia) Dinesh Rokaya (Thailand) Swapnil Bumb (India) Anka Koskova (Slovakia) Diana Buturca(Romania) Nicolas Cohn (Chile) Ahmed El- Sayed (United Arab Emirates) Victor Vega Morales (Puerto Rico/USA) Eva Sinic (Slovenia) Fairuz Atig (Tunisia) Flavia Joarza (Romania) Giacomo Armani (Romania/Italy) Davina Peh (Malaysia) Gorkem Sengun (Turkey) Jana Nakladova (Czech Republic) Karin Pokoma(Czech Republic) Jana Nakladova(Czech Republic) Magdalena Wiczak (Poland) Victor Palumbo (Italy) Monica Ferran (Slovenia) Murad Alrsheedi (Saudi Arabia) Petra Horakova (Czech Republic) Petronela Buiga (Romania) Pradeep Sharma (India) Ricardo Fillipe Mendes (Portugal) Rifqi Aulia Destiansyah (Indonesia) Sajjad Ashnagar (Iran) Sara Ehsani (Iran) Tarek Omran (United Arab Emirates) Andrei Baltaev (Russian Federation) Tigran Gyokchyan (Armenia) Juan Guttierez Quintero (Columbia) Veronika Piskova (Czech Republic) Wika Ardianti Putri (Indonesia) Yana Sadykova (Kazakhstan) Zen Feng Chong (Malaysia) Ahmad Salah (Sudan) Kiki Saputri (Indonesia) Tsai, Chi - Hasuan (Republic of China Taiwan) Patrick Bannerman-Agbesi (Ghana) Taher Elkowiery (Egypt) Augusto Elias (Puerto Rico/USA) Abdulla A Alajmi (Sudan) Mustafa Gurkan (Turkey) Resat Batuhan Cetiner (Turkey) Busra Zengin (Turkey) Nur Oztoprak (Turkey) Ferdiye KÜÇÜK (North Cyprus) Melike Atalar (Turkey) Omar Al Bairat (Morocco) Faniran Felix (Nigeria) Sina Saygili (Turkey)

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In vitro evaluation of dental enamel exposed to medicines used in pediatric cardiology Gokay Karapinar1; Dr.Yegane Guven2; Dr.Sule Batu2; Dr.Ferda Dogan3 1 Istanbul University, Faculty of Dentistry, Department of Oral and Maxillofacial Surgery, PhD Student 2 Istanbul University, Faculty of Dentistry, Department of Biochemistry; 3 Istanbul University, Faculty of Dentistry, Department of Public Oral Health Authors declare no conflict of interest.

Corresponding Author: Gokay Karapinar E-mail: gokaykarapinar@gmail.com Address: Istanbul Universitesi, Dis Hekimligi Fakultesi, Agiz Dis Cene Cerrahisi Anabilim Dali, Capa/Istanbul

Abstract: Purpose: The purpose of the present study was evaluations of dental enamel exposed to acidic medications such as acetylsalicylic acid, furosemide, captopril, and propranolol in vitro.

propranolol and furosemide had an erosive effect on dental enamel. Considering the long term and regular usage of these medications, this study demonstrated erosive potential of these medicines.

Methods: Tablets were crushed in a mortar and dissolved in 10 ml distilled water. Bovine teeth which were divided into 37 enamel blocks were used in the experiments. Enamel blocks were randomly distributed into the following 6 groups: Group I: acetylsalicylic acid, Group II: furosemide , Group III: captopril ,Group IV: propranolol , Group V: 10 mM citric acid(control) , Group VI: distilled water In order to immerse in the medicine solutions, 7,065 mm2 windows were opened on every enamel block.

Two windows were opened on one of the blocks which enable to observe the difference between medicine exposed block and the one with clean surface in SEM (Scanning Electron Microscope). Each tooth was put into the chambers which contain 500 μl medicine solution and than kept in the chambers for thirty minutes. Afterwards, dissolved phosphate was determined spectrophotometrically.

KEYWORDS: dental erosion, acidic medicines, pediatric cardiology

Results: The pH values varied between 2.96 and 5.1.

Acetylsalicylic acid (75 mg) tablet water solution showed the lowest pH. The highest dissolved phosphate obtained for Captopril (25 mg) tablet solution (0,3192μg) and for acetylsalicylic acid (75 mg) tablet water solution (0,2977 μg), respectively. Scanning electron microscopy analysis showed prominent erosive patterns.

Conclusion:

Acetylsalicylic

acid,

captopril,

Introduction In the last decade, tooth erosion has drawn an increasing attention as a risk factor for tooth damage.

Dental erosion is defined as “loss of dental hard tissue by a chemical process that does not involve the influence of bacteria” (1), or “the result of a pathologic, chronic, localized loss of dental hard tissue that is chemically etched away from the tooth surface by acid and⁄ or chelation without bacterial involvement ”(2). It occurs as a result of acidic attacks during simultaneous unsaturation of both hydroxyl- and fluorapatite in saliva, causing loss of dental hard tissue, layer by layer.

The etiology of dental erosion is often complex and multi-factorial (3). There are extrinsic and intrinsic factors that are causing dental erosion. Extrinsic factors are factors like acidic foods, beverages and medications which we put into our mouth.

Intrinsic factors may be diseases and consequences of diseases where acidic contents of the stomach reach the oral cavity and thereby pose a threat to the oral health. Some intrinsic causes of dental erosion include recurrent vomiting in psychological disorders such as anorexia and bulimia and regurgitation of gastric contents due to gastrointestinal problems (4).

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Erosion results in the softening of enamel and dentine which, in combination with mechanical factors such as abrasion and attrition, results in accelerated and pathological wear of the teeth (1). In vitro studies have shown that acidic medicines can reduce enamel hardness of primary teeth, influence enamel roughness, and cause morphological enamel alteration; however, little is known about the effect of oral medicines on tooth surface under erosive conditions (5).

Studies investigating the physicochemical parameters of pharmaceutical products have provided valuable information on their cariogenic and erosive potential by determining hydrogen potential (pH), titratable acidity, soluble solids content and total sugars (6).

In this study, we focus on the potential erosive effects of the medicines that are given regularly and long term to children in pediatric cardiology clinics. In Istanbul University, Istanbul Faculty of Medicine, Pediatric Cardiology Clinics, patients are given medicines after crushing and mixing it with a water solution as a clinical protocol. As a result of this, tooth surfaces are being exposed to medications directly. Therefore, the aim of this project is to evaluate dental enamel exposed to some acidic medicines.

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A. Preparation of Bovine Teeth: Crowns were sectioned from the roots. Tooth blocks obtained from every crown using micromotor (Kavo).

Thirty seven teeth blocks were prepared from twelve bovine incisors stored in wet gauze at 4oC (Figure 1).

Before immersing in the medicine solutions, 7,065 mm2 stickers were pasted on every enamel block (Figure 2 and 3). Two stickers were pasted on one of the blocks which enable to observe the difference between medicine exposed block and the one with clean surface in Scanning Electron Microscope (SEM). Every block was coated with a acid resistant nail varnish and kept until it becomes dry (Figure 4 and 5). The tooth blocks were kept in a 1 mM calcium phosphate + 1mM Fluoride solution overnight in order to standardize the teeth prior to measurements (7). Afterwards, blocks were randomly distributed in six groups for placing into different solutions.

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Figure 1,2, 3 - Preparation of Teeth

phosphate was determined spectrophotometrically (Shimadzu UV-1601 UV visible spectrophotometer). b) SEM analysis: One window was opened from the two sticker pasted block and immersed in Captopril (25 mg) water solution. Then, other window was opened so that we can examine the difference in SEM(FEI Quanta Feg 450) with an acceleration voltage of 10 Kv (5). After coating with gold (Figure 9), the block was mounted on an aluminum stub to place in SEM. SEM micrographs were taken at 150, 1000 and 5000 magnification (Figure 10).

B. Preparation of Medications: Four pharmaceutical preparations commonly used in pediatric cardiology were selected (Table 1). The experimental groups were as follow: Group I: acetylsalicylic acid; group II: furosemide; group III: captopril; group IV: propranolol; GroupV: citric acid (positive control); and Group VI: distilled water (negative control) The selected pharmaceutical preparations were solid tablets. Tablets were crushed in a mortar and dissolved in 10 ml distilled water. (Figure 6) The pH of the solutions of tablets were measured twice using the pH meter.

C. Experimental Phase a) Phosphate determination and measurement of pH: Firstly, baseline phosphate determination of each medicine solution was performed. The stickers that were pasted on teeth were removed carefully. 7,065 mm2 windows were opened on every tooth block. (Figure 7) Every tooth block was put into the chambers which contain 500 μl medicine solution and than kept in the chambers for thirty minutes (Figure 8) (7). Afterwards, dissolved

D. Statistical Analysis: SPSS program was used for statistical calculations; furthermore, correlation factors, Tukey’s test, T-test were utilized to compare the groups.

Results The pH values varied between 2.96 and 5.1.

Acetylsalicylic acid (75 mg) tablet water solution showed the lowest pH. The highest dissolved phoshate obtained for 25 mg Captopril tablet solution (0.3192μg) and for 75 mg acetylsalicylic acid tablet water solution (0.2977 μg), respectively.

According to One-way ANOVA, there was statistically significance among groups in terms of pH and phosphate dissolution (p < 0.001). Citric acid caused the highest phosphate dissolution among the groups.

There is statistically significance between citric acid and the other groups (p < 0.001). Comparing the groups among each other, there is statistically significance in terms of dissolved phosphate related to pH (p < 0.001).

SEM analysis showed prominent erosive patterns (Figure 11-12)

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Figure 4

Figure 6

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Figure 5

Figure 7

Discussion The present study was performed in order to increase the knowledge of possible effects on dental hard tissues caused by pharmaceutical preparations used regularly and on a long-term basis in children with severe heart disease.

Various long-term medications which are given orally in different dose forms were selected for the present study.

In this study, especially acetylsalicylic acid, captopril, propranolol and less in amount furosemide pointed out an erosive effect on dental enamel. Considering the long term and regular usage, this study demonstrated erosive potential of these medicines.

The pH values varied between 2.96 and 5.1. 75 mg Acetylsalicylic acid tablet water solution showed the lowest pH. The highest dissolved phoshate obtained for 25 mg Captopril tablet solution (0.3192μg) and for 75 mg acetylsalicylic acid tablet water solution (0.2977 μg), respectively. Also, it is showed on the SEM analyses that captopril caused dental erosion on the surface enamel.

In another study, which was published by Rosen et al (8), the lowest pH was recorded for the captopril water

solution. In addition, the highest dissolved phosphate was obtained for 12.5 mg captopril tablet water solution.

Moreover, 0.7 mM phosphate were dissolved from 75 mg acetylsalicylic acid tablet water solution (8).

In vitro studies have shown that an acid medication may reduce enamel hardness and influence the enamel roughness (9). Furthermore, an in vivo investigation observed that frequent medications’ intake might constitute possible etiological or aggravating factors for severe dental erosion (10).

As the composition of teeth is variable due to genetic influences and environmental conditions, such differences may lead to large variations in their response under acidic conditions (7). The present study has its own limitations where it was done on bovine teeth and all the parameters were measured in vitro. However, researches have shown no significant difference between human teeth and bovine teeth (11). The exact contribution of various acidic properties of medicines to erosive potential is unclear, especially when the in vivo situation is considered (2). Further studies should be conducted to include the effect salivary buffering has on the acidic potential of these medications.

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Figure 8

Figure 9

Figure 10

Figure 11

Conclusion The present study showed that there is a significant risk of the erosion of dental hard tissues by medications commonly uses in pediatric cardiology clinics. This study provides information on the erosive potential of various pediatric medicines. It also provides a perspective on risk factors for children with chronic disease on longterm medication. It also aims to raise awareness among pediatric practitioners about potential risk of tooth surface loss of children from their medication. It is important that children with medical conditions who need long-term oral medication be targeted for prevention of dental disease.

References 1. ten Cate JM, Imfeld T. Dental erosion, summary. Eur J Oral Sci 1996; 104: 241–244 2. Arora R1, Mukherjee U, Arora V. Erosive Potential of Sugar Free and Sugar Containing Pediatric Medicines Given Regularly and Long Term to Children. Indian J Pediatr. 2012 Jun;79(6):759-63.

3. Lussi A1, Jaeggi T. Erosion--diagnosis and risk factors.

Clin Oral Investig. 2008 Mar;12 Suppl 1:S5-13.

4. Linnett V, Seow WK. Dental erosion in children: a literature review. Pediatr Dent. 2001;23(1):37-43.

5. Valinoti AC, Pierro VS, Da Silva EM, Maia LC. In vitro alterations in dental enamel exposed to acidic. Int J Paediatr Dent. 2011;21(2):141-50.

6. Xavier AF1, Moura EF, Azevedo WF, Vieira FF, Abreu MH, Cavalcanti AL. Erosive and cariogenicity potential of pediatric drugs: study of physicochemical parameters. BMC Oral Health. 2013;13:71 7. Rosén L, Rydberg A, Sjöström I, Lundgren T, StecksénBlicks C. Acidity and in vitro effects on dental hard tissues of pharmaceutical preparations used in paediatric cardiology Submitted to: BMC pediatrics.

8. Rosén L. Dental caries and background factors in children with heart disease. (2011).

9. Costa CC, Almeida ICS, Costa Filho LC. Erosive effect of an antihistamine- containing syrup on primary enamel and its reduction by fluoride dentifrice. Int J Paediatr Dent.

2006;16:174–80

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Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

10. Peres KG, Oliveira CT, Peres MA, Raymundo MS, Fett R. Sugar content in liquid oral medicines for children. Rev Saúde Pública. 2005;39:486–9.

11. Yassen GH1, Platt JA, Hara AT. Bovine teeth as substitute for human teeth in dental research:a review of literature. J Oral Sci. 2011;53(3):273-82.

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Quality of Periapical Radiographs Taken By Undergraduate Dental Students at Qassim University Almogbel, Abdulmajeed Abdullah A. (BDS) 1, Alolayan, Abdulrahman Abdullah S. (BDS) (2) 1. Demonstrator at Qassim University College of Dentistry, Department of Orthodontics and Pediatric Dentistry.

2., General Dentist at Prince Sultan Military Medical City, Dental and Oral maxillofacial Department.

“No conflict of interest”

Abstract: Purpose: The periapical radiographs are the most common type of dental radiograph used.

The purpose of this study was to evaluate the quality of periapical radiographs (the bisecting angle technique) taken by undergraduate dental students at Qassim University (QU) and the types of errors in different anatomical location.

Methods: A total of 272 periapical radiographs were collected from dental clinic at QU. The radiographs were taken by undergraduate dental student at QU. The radiographs were evaluated by two radiologists.

Results:The most frequent errors were processing errors (23.5%), cone cut (20.2%), and incorrect vertical angulation (15.1%).

Conclusion: Dental clinicians must be fully aware about a variety of technical skills and the basic knowledge of radiology..

KEYWORDS: x-ray, errors, undergraduate dental students.

Introduction The use of x-rays is an integral part of clinical dentistry, and radiographic examination is necessary on the majority of patients. As a result, radiographs are often referred to as the clinician’s main diagnostic aid (1). Periapical radiographs become extremely important in diagnosing the majority of pathologic condition as well as assisting in endodontic treatment.

However, the correct radiographic interpretation relies on the availability of basic knowledge, quality images, and absence of technical and processing errors. Studies have reported the types and frequency of errors incurred when radiographs are taken and processed by dental students (2-4) and professionals (5, 6). Regardless of the technique employed (bisecting or paralleling), the most commonly found errors are: film and/or radiation beam positioning, image contrast (light or dark), vertical and horizontal angulations, processing, inadequate fixation, and presence of stains and streaks (2-4).

Previous studies have shown that many factors, such as radiographic technique, use of film holder and anatomical location of the teeth, affected radiographic errors (7-9). A recent study revealed that incorrect film placement, incorrect angulation and cone cutting were the most frequently types of errors (10). In addition, the most frequent regions for errors were the maxillary molar, maxillary premolar and mandibular molar regions, respectively (10). The purpose of this study was to evaluate the quality of periapical radiographs (the bisecting angle technique) taken by undergraduate dental students at Qassim University (QU) and the types of errors in different anatomical location.

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Materials and Methods A total of 272 periapical radiographs were collected from dental clinic at Qassim University (QU). An informed consent from the director of the clinic was given. The radiographs were taken by undergraduate fourth (males N =104 radiographs, females N = 49) and fifth year (males N = 119 radiographs) dental student at QU. This study was based on evaluation of a randomly gathered periapical radiographs taken using the bisecting angle technique and processed with manual film processor. The evaluation was done by two radiologists (Assistant professor at College of Dentistry QU, Radiology Department) relied on the following errors:

incorrect vertical and horizontal angulations , cone cut , low and high density, processing errors and film positioning.

The anatomical distribution of the samples was divided into eight segments and each segment has particular code number (Table 1).

The study results were expressed by mean values and standard deviations (SD). P-values less than 0.05 were considered statistically significant.The data were analyzed using an SPSS (version17) statistical program package.

Blurred and reverse image, dot artifact, apices cut off , crown not shown , area of interest not shown , distortion ,

Figure 1 - High density image

Figure 2 - Cone Cut Image

Figure 3 - High density image

Figure 4 - Cut Image (Apices not shown)

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Results A total of 272 periapical radiographs were evaluated.

Table 2 shows proportion of error types. The most frequent error was processing errors (23.5%), cone cut (20.2%) and, incorrect vertical angulation (15.1%), respectively.

However, no the blurred or reversed image was observed.

locations where the samples have been taken were maxillary molars, mandibular molars, maxillary premolars, and maxillary canine, respectively. The less frequent anatomical locations were mandibular canine and mandibular anterior, respectively.

Table 3 shows a comparison between 4th and 5th year male students regarding the periapical radiographic errors. The comparison between 4th and 5th year male students showed no statistically significant difference except in processing errors and crown not shown. The processing errors were found 9.6% in 4th year and 43.7% in 5th year (p < 0.001), and the crown not shown was found 0.8% in 5th year while 14.4% in 4th year (p <0.001).

In the processing errors, the most errors were found in mandibular premolars (31.5%), maxillary premolars (27.3%), and maxillary anterior (25.0%) with no statistically significant difference (p = 0.248). The cone cuts were mostly found in maxillary molars (32.4%) and mandibular molars (27.4%), while none were found in the maxillary anterior, mandibular anterior and canine area (p = 0.001).

Incorrect vertical angulations were mostly detected in maxillary anterior (35.7 %) followed by mandibular premolar (27.8%) and maxillary canine (25.8%) (p = 0.003). A statistically significant difference was found for apices cut off error (p = 0.033. Apices cut off error had not found in maxillary and mandibular anterior and canines, but it was found mostly in mandibular molars (17.8%) and mandibular premolars (16.7%). No statistically significant differences were found for the other errors.

Table 4 presents a comparison between periapical radiographic errors of 4th year male and female students. The only statistically significant difference between 4th year males and females was in incorrect vertical angulations which was 6.1% in 4th year females and 20.2% in 4th year males (p = 0.026).

Table 5 presents the distribution of errors according to the anatomical location. The most frequent anatomical

Table 1. The anatomical distribution of the samples

Table 2. Distribution of error types

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Picture 5 - Apices cut off and incorrect vertical angulation

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Although there was no statistically significant difference between 4th and 5th year male students in most of the radiographic errors, processing errors and crown not shown demonstrated a statistically significant difference.

Contrary to expectations, the processing errors revealed 9.6% in 4th year and 43.7% in 5th year. A possible explanation for this might be a lack of adequate knowledge about the basic of processing. In addition, the 5th year students have a lot of clinical requirements to be finished.

Therefore, they might attempt to finish the processing in hurry. On the other hand, crown not shown was found 0.8% in 5th year while 14.4% in 4th year. Therefore, it seems possible that these results are due to the 4th year students have less experience in radiographic practice.

Discussion The errors in periapical radiographs can be categorized into to the followings: the x-ray equipment, the image receptor (film or film/screen combination), processing, the patient, the operator, and the radiographic technique (11). Errors related to the x-ray equipment and the image receptor has been minimized as the result of developments in the film industry (10).

The present study focused primarily on the periapical radiographic technique errors, including blurred and reverse image, dot artifact, apices cut off, crown not shown, area of interest not shown, distortion, incorrect vertical and horizontal angulations, cone cut, low and high density, processing errors, and film positioning.

In this study, the most frequent errors were processing errors (23.5%), cone cut (20.2%) and incorrect vertical angulation (15.1%). However, the incorrect angulation was the most frequent error reported in other conducted study (10). Those findings can be in agreement with the present study if the incorrect angulation would be considered as one error (horizontal and vertical)(24.3%).

In a previous study, the rates of error types were 32.74%, 32.33%, 19.86% for incorrect angulation, incorrect film placement and cone cutting, respectively (10). The present findings corroborate their result regarding to the incorrect angulation and cone cut error. In contrast, the incorrect film placement (4.4%) and processing errors (23.5%) were observed in this study distinct to several studies (10,16,17). This could be attributed to the fact that a manual film processor was used in the present study unlike the other studies which used an automatic film processor.

Table 3- Distribution of errors for male 4th and 5th year students

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The results of this study showed the only statistically significant difference between 4th year males and females was in incorrect vertical angulations which was 6.1% in 4th year females and 20.2% in 4th year males. This might be because the fact that patientsâ&#x20AC;&#x2122; flow at female clinics is lesser than male clinics. Therefore, the samples that have been collected from the female were smaller in number.

The cone cuts were mostly found in maxillary molars (32.4%), mandibular molars (27.4%), and maxillary premolars (21.2%). This result was similar to that of previous studies (2,3,10).. Previous study suggested that the maxillary molar region may be a particular problem area because of tongue movements and gag reflex for some patients and vertical angulation may seem to be relatively indistinct for clinicians.10 Aydin et al reveled incorrect angulation was most frequent in the maxillary molar region followed by the maxillary premolar, maxillary anterior and maxillary canine regions (15).

However, in current study the Incorrect vertical angulations were mostly detected in maxillary anterior (35.7 %) followed by mandibular premolar (27.8%) and maxillary canine (25.8%). The possible explanation for the high percentage at maxillary anterior is the anatomical angulation of the jaw.

The apices cut off error was not found in maxillary and mandibular anterior and canines, but it was mostly present for mandibular molars (17.8%). This higher prevalence could be due to the fact that the floor of the tongue pushes the periapical radiographic film upward. Therefore, for some patients, it is not comfortable to place the film in the correct position because they tend to elevate the film from the intended area.

Conclusion Dental radiography has an essential role in dentistry which allows dentists to diagnose cavities, lesions and other conditions that they otherwise would not be able to detect during a regular clinical examination. This study was set out to see the quality of taking radiographs of undergraduate dental students in QU. The result has shown that most frequent error was processing errors cone cut and incorrect vertical angulation. In addition, maxillary molars, mandibular molars, maxillary premolars, and maxillary canine were found as the most frequent locations where the radiographs were taken from.

The dental clinician must master a variety of technical skills in addition to understanding background scientific knowledge related to the radiology to minimize the needs for radiographic retake during training periods for undergraduate dental students, and consequently decrease the exposure to patient, clinician, radiology staff and environment.

Table 4- Distribution of errors for male and female 4th year students

Acknowledgment The authors would like to send a special thankfulness, appreciations and grateful to Dr. waleed samir assistant professor at College of Dentistry QU, Radiology Department, for his supervision and great support. Dr. Abdel Aleem Santawy assistant professor at College of Dentistry QU, Radiology Department for helping us. Dr.Ramy Elmoazen lecturer at Community Department of Qassim University for his help in statistical analysis. Dr.Ahmed Al-hujaylan lecturer at English Language department of Qassim University for revising the grammar of the article and to all our colleagues whom participating and supporting us.

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Table 5 - Anatomical Distribution of Errors

Continue Table 5

References 1.Whaites, Eric. Essentials of Dental Radiography and Radiology. Edinburgh: Churchill Livingstone, 3rd Edition, 2003.

2.Mourshed F. A study of intraoral radiographic errors made by dental students.

Oral Surg Oral Med Oral Pathol.

1971 Nov;32(5):824-8.

3.Patel JR. Intraoral radiographic errors. Oral Surg Oral Med Oral Pathol. 1979 Nov;48(5):479-83.

4. Patel JR, Greer DF. Evaluating student progress through error reduction in intraoral radiographic technique.

Oral Surg Oral Med Oral Pathol. 1986 Oct;62(4):471-4.

5. Eliasson S, Lavstedt S, Wouters F, Östlin L. Quality of intraoral radiographs sent by private dental practitioners for therapy evaluation by the Social Insurance Office. Swed Dent J. 1990 May/ Apr;14(2):81-8.

6. Svenson B, Eriksson T, Kronström M, Palmqvist S. Image quality of intraoral radiographs used by general practitioners in prosthodontic treatment planning. Dentomaxillofac Radiol. 1994 Feb;23(1):46-8.

7. Petrikowski CG, ElBadrawy H, Boehlau EE, Grace MGA. Interobserver variability in pediatric radiographic quality assessment. J Can Dent Assoc. 1998 Jan;64(1):36-41.

8. Bean L. Comparison of bisecting angle and paralleling methods of intraoral radiography. J Dent Educ 1969;33:441.

9. Tamse A, Kaffe I, Fishel D. Zygomatic arch interference with correct radiographic diagnosis in maxillary molar endodontics. Oral Surg Oral Med Oral Pathol 1980;50:563.

10. Ilkay Peker, Meryem Toraman Alkurt. Evaluation of Radiographic Errors Made by Undergraduate Dental Students in Periapical Radiography. nysdj • august/september 2009.

11. Whaites E. Essentials of Dental Radiography and Radiology 3rd Ed. London: Mosby, 2002;177.

12. Mourshed F.A study of intraoral radiographic errors made by dental students.Oral Surg Oral Med Oral Pathol 1971;32:824.

13.

Patel JR,Greer DF.Evaluating student progress through error reduction in intraoral radiographic technique.

Oral Surg 1986;62:471.

14. Paksoy CS, Cebeci AI. The errors on intraoral radiographs. J Ankara Uni Fac Dent 1992;19:49.

15. Aydin Ü, Alasya D, Erdem M. Radiographic errors made by dental students. J Gazi Uni Fac Dent 2004;21:107.

16. Karakurumer K, Özden T, Par S, Dogan N. The investigation of the errors on the radiographies taken by bisecting angle technique. JAnkara Uni Fac Dent 1990;17:191.

17. Svenson B, Eriksson T, Kronstrom M, Palmqvist S. Image quality of intraoral radiographs used by general practitioners in prosthodontic treatment planning.

Dentomaxillofac Radiol 1994;23:46.

18. Langland OE, Langlais RP, Preece JW. Principles of Dental Imaging 2nd Ed. USA: Lippincott Williams & Wilkins, 2002;155.

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Mineral Composition of Enamel and Dentin of Intact Teeth in Patients with Thyroid Gland Pathology in Belgorod Region, Russian Federation Peshkova Ella. Postgraduate student (BelSU) Federal State Autonomous Educational Institution of Higher Professional Education “Belgorod State National Research University” E-mail: ep17@students.uwf.edu Author declares no conflict of interest

Abstract: Purpose: The purpose of the present study was to investigate the effects of thyroid gland pathology on macro and trace elements of teeth.

Methods: We examined two groups of patients: healthy patients and patients with thyroid disorders.

The sample was comprised of 32 extracted teeth for orthodontic and periodontal indications from patients 18 to 50 years old. The changes in macro and micro trace elements (dietary minerals) composition of dental hard tissues in healthy subjects and patients with thyroid disorders were investigated using scanning electron microscopy (FEI Quanta 200 3D, Eindhoven, Netherland).

Results:Major changes were found in the calcium and phosphorus levels. Comparative analysis of the contents of magnesium and sulfur in the enamel and dentin showed that their contents increased in the teeth of patients with thyroid disorders.

Conclusion: We described some visual characteristics of teeth in patients with thyroid gland pathology. These data may be used in diagnostic, treatment, and prophylactic of caries lesion in patients with thyroid gland disorder.

KEYWORDS: thyroid gland pathology, hypothyroidism, teeth, enamel, dietary minerals, scanning electron microscopy

Introduction Endocrine pathology has a high prevalence in human society. According to WHO (2007), the level of iodine is below the normal range in 2 billion people (34% of the world population) (1).

According to the American Association of Thyroid

Problems about 20 million Americans have thyroid disease, which about 60% are not diagnosed.

The study of Shalu C. et al. (2011) found some changes in the morphology of the teeth in children such as delayed eruption of primary and permanent teeth, and enamel hypoplasia. The reason of those alterations was hypothyroidism. The hypothyroidism changes the macro and trace elements composition of the dental hard tissues. The hyperthyroidism causes demineralization of the bone tissue, leading to reduction of calcium and phosphorus levels in the skeleton structure including tooth enamel (2).

The thyroid gland is one of the important regulators of metabolism. Scientists have recently started to review relationship between thyroid gland pathology (TGP) and oral-status (2-4). The goal of the present study is to investigate TGP influences on macro and trace element of teeth. We suspect that amount of the elements in hard teeth tissues affects caries resistance among healthy people and people with TGP.

Materials and Methods The sample for the present study was comprised of 32 intact teeth, which were extracted for orthodontic and periodontal indications from 18 to 50 years old subjects in Belgorod, Russia. The teeth were divided into two groups: healthy patients without thyroid gland pathology (control) and patients with thyroid gland pathology (test). Morphological examination was performed on extracted premolars and molars. Samples were cut by longitudinal or transverse cuttings. The surface of the samples was washed with gel-etching for enamel and dentin.

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Samples were monitored examined by a scanning electron microscopy (FEI Quanta 200 3D, Eindhoven, Netherland) with a function of non-contact detection of macro-and trace elements at Center of Nanotechnology of Belgorod State University, Russia.

Results The present data revealed differences in the mineral composition of the teeth between the test and control groups. The data is presented in the Table 1. Enamel of the control group (42.21 ± 1.57%) contained 4% more calcium than the test group (38.15 ± 2.16%). Teeth of patients with TGP contained less phosphorus (18.88 ± 0.93%) than teeth of patient without TGP (20.01 ± 0.27%). In addition, the results showed a reduction of the Ca / P ratio in the tooth structure of patients with thyroid disorders compared to the control group.

The oxygen content was significantly higher in the enamel of patients with thyroid disorders (39.84 ± 1.26%) compared to that of patients without thyroid disorders (35.76 ± 1.12%). Enamel of the teeth in the test group had two times higher sodium content (1.09 ± 0.21%) than teeth of the control group (0.58 ± 0.16%). The chlorine content in the teeth with thyroid disorders (0.25 ± 0.11%) was 3.4 times less than that of teeth of healthy patients (0.85 ± 0.18%).

A slight presence of sulfur (0.06 ± 0.03%) was found

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in the enamel of teeth with TGP, but that mineral was absent in teeth without TGP. Furthermore, enamel of healthy teeth did not have silicon, but that of control teeth contained silicon (1.02 ± 0.33%).

We hypothesize that TGP may be the cause of the sulfur appearance in the enamel and dentin; however, the effects of changes in the percentage of sulfur in the solid tissues of the tooth were not thoroughly explored. This change reflected the presence of pathological processes because the exchange of sulfur was controlled by the same factors that regulate protein metabolism (thyroid hormones).

Analysis of the results in the study of macro and trace elements composition in the dentin found statistical differences between the patients with thyroid disorders and control group. The calcium level was significantly lower in the test group compared to the control group. There was statistically significant reduction (3.14%) in phosphorus level in tested group compared to the control group (19.83 ± 0.34%). Moreover, there was higher oxygen content in the test teeth compared to the control teeth. Teeth of patients with TGP revealed silicon content of 0.74 ± 0.28%, while there was no silicon present in the dentin of healthy patients. No significant differences of sodium and potassium in the dentin were found between the two groups.

Table1 Mineral composition of enamel and dentine of intact teeth in patients with and without thyroid gland pathology

*- the differences are significant to the group of healthy teeth at p <0.05

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Discussion

The purpose of this study was to determine the effects of TGP on the amount of macro and trace elements in tooth structure. The present study identified that some group elements are affected by the pathological changes. The first group elements includes calcium, phosphorous, chlorine, and sulfur; the second group - oxygen; third - sodium. The data revealed a statistically significant decrease in calcium content and a tendency to decrease in phosphorus content of the enamel, which is an unfavorable sign corroborated by scanning electron microscopy.

Our data revealed a change in the ratio of the mineral composition of dental hard tissues in patients with TGP. The structural changes in the hard tissues of teeth occurred in the context of demineralization, especially calcium and magnesium that lead to the insolvency of local compensatory - defense mechanisms. The caries resistance is found to be higher in healthy subjects compared to patients with thyroid pathology. The density depends on the structure of the enamel of high mineral content, and determines the resistance to pathological processes. Magnesium and silicon enhance the mineralization process and affect the densities of enamel.

Teeth of patients with TGP revealed silicon content of 0.74 ± 0.28%, while there was no presence of silicon in dentin of healthy patients. According to Skalniy AV (2003), the increased silicon content indicates a lesion of water-salt metabolism. Silicon promotes the synthesis of collagen and participates in bone morphogenesis.

Comparative analysis of the content of magnesium in the dentin showed a 3.5 fold increase in the teeth with thyroid disorders. Our theory is that dysregulation of magnesium exchange was caused by overactive thyroid gland. No significant differences of sodium and potassium contents in dentin of the teeth studied were found.

Among patients with thyroid diseases, we observed that patients reported an increased hypersensitivity of dental hard tissues with localization predominantly in the cervical region, followed by the formation of cavities. These changes were accompanied by a disturbance of mineral metabolism in the hard tissues of the tooth. Identification of structural and functional changes in the affected teeth of patients with thyroid diseases is equally important during the stages of diagnosis and the phases of subsequent treatment.

The present findings are consistent with those of

Maximovsky YuM (1981) who found changes in the macro and trace element composition of dental hard tissues leads to a higher frequency of cervical carious lesion. We disclose the data confirming that the hyperthyroidism causes demineralization of not only the bone, (2) but also the teeth.

Development of hard tissue lesions of teeth, their early clinical manifestations, and outcome and nature of complications are largely determined by visual observation of hidden factors, which requires new diagnostic tools.

Conclusion Mineral metabolism in hard tissues has raised more interest in recent years due to the unique properties of the enamel and dentin that must be considered in the prevention and treatment of pathological changes. The present data suggests influence of thyroid disorders in the hard tissues of teeth. The improvement of methods and techniques allows a more in-depth study of the mechanisms of these processes.

Acknowledgment: Ph.D., professor, Pavlova TV (BelSU, Russia); head of laboratory department, Kolesnikov DA (BelSU, Russia); Ph.D., Cavnar P (UWF, USA), who helped me to do this research.

References 1. De Benoist B, McLean E, Andersson M, Rogers L. (2008). Iodine deficiency in 2007: global progress since 2003. Food Nutr Bull, 29(3), 195-202.

2. Kamilov KP, Kostina КК. Features of mineral exchange of enamel at patients with thyroid gland hyperfunction. Vrachaspirant. 2010;41(4):10-14.

3. Maksimovsky Y. Porajeniya tverdih tkaney zubov pri giper- i gipofunktsii zhitovidnoi jelezi, ih profilactika i lechenie. Avtoref. dis.d-ra med. nauk. Moskwa; 1982.

4. Shalu C, Manish B. Oral manifestations of thyroid disorders and its management. Indian J Endocrinol Metab. 2011;15(Suppl 2):S113-6.

5. Skalny AV. The trace elements excesses and deficiencies in children in Russia // Proceed. of 7th Europ Nutr Conf, Vienna, Hofburg. 1995;76: 24-28.

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