مجله تحقیق در علوم دندانپزشکی
سال هجدهم شماره 4 (پیاپی 70، زمستان 1400)

Asymmetric extractions have been proposed as potential treatment options to correct Class II subdivision malocclusion, suggesting that most side effects associated with asymmetrical mechanics can be avoided, however the post-treatment arch form may not be symmetrical. Therefore, the aim of this study was to determine the post-treatment effects of unilateral premolar extraction on the maxillary dental arch in Class II subdivision malocclusions.

Thirty-four patients with Class II subdivision malocclusion were treated for tooth extraction were selected. Patients were divided into two groups treated with unilateral and bilateral extractions in the maxilla.  Dental arch symmetry was assessed using maxillary digital 3D casts and anterior-posterior, vertical and transverse changes of upper dental arch was calculated. The amount of displacement of the molars and canines were recorded and the changes in inclination of incisors was also measured on lateral cephalography. The T-test and  test was used for each index with normal distribution and Mann-u Whitney test was used for specific data with abnormal distribution.

The amount of molars asymmetry in the unilateral extraction group in the transverse dimension was 0.15 mm and in anterior-posterior dimension 4.55 mm more than bilateral extraction group which was statistically significant (p≤0.001).  However, in the vertical plane, the molars showed statistically insignificant differences.   The amount of canines’ asymmetry in the unilateral extraction group in the transverse, vertical and anterior-posterior dimension was 0.18 mm, 0.58 mm and in 0.60 mm respectively, when compared with bilateral extraction group which was statistically significant (p≤0.0001). The difference in the inclination of the upper anterior teeth at the end of treatment was also statistically significant.

The effect of unilateral premolars extraction on the symmetry of the dental arch form is significantly different from bilateral premolars extraction.  Asymmetry of the molars at the end of treatment, the amount of anterior displacement of the molars on the extraction side and the amount of posterior canine displacement on the traction side were clinically significant.

The opacity of dental ceramics has important role in final appearance of all ceramic restorations. opacity of super high translucent zirconia is not clearly determined.The aim of this study was evaluating the opacity of two super high translucent zirconia (zolid fx and DD cubeX2) and lithium disilicate reinforced glass ceramic(IPS e.max CAD LT).

In this experimental study, 30 ceramic discs with 1 mm thickness and 10 mm diameter in two groups of super high translucent zirconia (zolid fx and DD cubex2) and one group of lithium disilicate reinforced glass ceramic (IPS e.max CAD LT) were fabricated(n=10). For determining the contrast ratio (CR), spectrophotometer was used to measure Y parameters of each sample in black and white backgrounds. One-way ANOVA and Tukey Post Hoc statistical tests were used to analyze the data. Level of significancy was 0.05.

The mean of CR in the three groups of IPS e.max CAD LT ، zolid fx and DD Cubex2 were 0.97 ± 0.002, 0.96 ± 0.004 and 0.96 ± 0.005 respectively. Significant differences were not found in the CR values of three groups (P = 0.2).

Regarding the limitation of this study, Opacity of three ceramic were similar.

Considering that 67 to 90 percent of dental caries in the age of 5 to 17are related to occlusal surface on molars,the use of fissure sealant has been reported as effective in reducing caries. The aim of this study was to assess the clinical effectiveness of fissure sealants placed on permanent first molars between 2016 and 2018 in pediatric department of Dental Faculty, Tehran Medical Sciences , Islamic Azad University.

In this cross sectional descriptive study, the files of patients in whom the first permanent molars fissure sealant was performed by dental students during 2016 to 2018 were extracted and assessed. Before the evaluation, the teeth were cleaned using tooth brush and paste . Fissure sealant retention was evaluated with probe and dental mirror on a dental chair.Data were processed by SPSS25 statistical software and logistic regression model was used to determine the effect of variables.In this study, P<0.05 was considered significant.

In 160 fissure sealants done , Complete retention 20.6% (33 teeth), partially retention loss 43.8 % (70teeth) and complete retention loss was  35.6 % (57 teeth) .

It seems, more than half teeth , last fissure sealant retention during time, more than 68 percent have no caries.

AFP (Atypical Facial Pain) is indicated as a pain sensation of oral mucosa without any visable mucosal lesions during clinical examination. The aim of this study was to evaluate of oral health related quality of life among patients with Atipical Facial pain,referred to Zahedan dental school and compare it with healthy people.

This cross-sectional study was performed on 48 AFP patients at Zahedan dental school and 96 healthy people. collection method was General Oral Health Assessment Index (GOHAI) questionnaire and demographic data. questionaire included 12 questions about oral health-related quality of life with 5 options.the data was analysed in spss software.

In case group 31.9% (15 people) of the patients were men and 68.1% (32 people) were women, and in control group 36.1% (35 people) of the patients were men and 63.9% (62 people) were women. the mean score of GOHAI in patients was 27.85±10.68 and in control group was 45.49±6.84 which indicators that the mean of oral health related quality of life between the two groups was statistically significant (P<0.001).

The results of this study showed that oral health-related quality of life in AFP patients is weaker than healthy people wich indicates that need for care to maintain of oral health of individuals who are Atipical Facial Pain.

The diffused melanotic pigmentation of oral mucosa is referred to any kind of brownish to black diffused and flattened macular and patch in physiologic or pathologic form. This view is important in aesthetic terms, the perception of malignancy, and association with systemic diseases, especially the endocrine glands diseases. Little local studies have been carried out that have many shortcomings; and in this age group, no research has been done in Tehran; hence, we made a study aimed to determine the frequency of the diffused melanotic pigmentation of the oral mucosa and related factors in dental students of Islamic Azad University of Tehran in 2018-2019.

This Cross-Sectional fstudy was performed by cross sectional method. according to a pilot study, 788 subjects were selected and examined through sequential sampling method. The cases were diagnosed clinically. The studied relevant factors included age; sex; smoking, skin color, systemic, syndromic, genetic diseases, as well as inflammatory mucosal diseases (Lichen Planus), etc. After collecting data, the incidence of diffused melanotic pigmentation of oral mucosa was determined by the software spss (version 11), and the role of its related factors was determined by using Chi Square test and regression analysis.

The distribution of diffused melanotic pigmentation of oral mucosa among 788 dental students of Islamic Azad University was 28.4%. Pigmentation in men was more prevalent than in women. Dark skin color and smoking had a significant correlation with the incidence of pigmentation (p-value<0.01).

the prevalence of diffused melanotic pigmentation of oral mucosa in dental students of Islamic Azad University of Tehran is considerable and in a significant relationship with the dark skin and smoking.

Thalassemia is a common hereditary disease which is one of the health problems in Iran due to its high prevalence. The aim of this study was to evaluate the dental health and treatment needs of patients with major thalassemia in Bandar Abbas.

This descriptive cross-sectional study was performed on 80 thalassemic patients referred to Bandar Abbas health centers. The control group consisted of 80 healthy individuals who were selected by age and sex similar to the patient group. The age range of participants was between 4 and 22 years old with an average of 12.36 ± 14.8 years. The demographic data were recorded in the questionnaire and then the caries and dental needs were determined by clinical examination. Data were analyzed by descriptive and analytical statistics using the SPSS-21 software.

The mean DMFT of permanent teeth in thalassemia and control group was 5.04 ± 5.07 and 2.9 ± 3.57 respectively, which according to Mann-Whitney test, there was a significant difference between the two groups (P value = 0.015). This rate in deciduous teeth for thalassemia and control groups was 5.59 ±3.36 and 4.05± 2.99, respectively (P value = 0.044). In thalassemia patients, the need for restoration (P value = 0.027) and root canal treatment (P value = 0.013) were higher. There was also a significant difference between DMFT and frequency of tooth brushing in both groups of thalassemia and control group (<0.0001).

Due to the higher level of DMFT in patients with thalassemia major, health education, preventive measures and dental treatments are necessary for these patients.

Lack of dentists' information about the diagnosis and treatment of endo-perio lesions is one of the main reasons for dental removing. Considering the importance of this issue, the present study aimed to investigate the knowledge and practice of senior dental students in Yazd about differentiation of endo-perio lesions and effective treatment of these lesions.

The present study was descriptive-cross-sectional. The instrument used in this study was a researcher-made and three-part questionnaire including: demographic information of students (age and sex), 14 questions that assessed student's knowledge about differential diagnosis of endo-perio lesions and 4 performance questions in this regard. Data were analyzed using SPSS software version 17, T-test, ANOVA statistical test and Pearson correlation coefficient. The significance level in this study was 0.05.

In this study, out of 52 students that participated, 23 (44.23%) were male and 29 (55.76%) females. The mean age of the samples was 25.19±2.09 with the age range of 23-36 years. On average, participants had 60.2% knowledge. There was a significant relationship between students' knowledge and age (P-value=0.028). There was no significant relationship between students' knowledge and sex (P-value=0.734), total GPA (P-value=0.237) and also between their performance and age (P-value=0.949), sex (P-value=0.061) and total GPA (P-value=0.284).

According to the results of this study, the knowledge and practice of studied dental students regard diagnosis and treatment of endo-perio lesions was moderate. It is recommended that educational interventions and appropriate strategies be adopted to promote students' knowledge and practice.

  The primary aim of orthognathic surgery is to improve the aesthetic parameters of the face and dentition and to transform it into an acceptable clinical standard, which is often associated with the secondary aim of improving occlusal function. The most common treatment option for maxillofacial abnormalities in Class III malocclusion patients is bimaxillary surgery, treatment planning of which requires complete knowledge of soft tissue adaptation with the underlying hard tissue movements,so a complete treatment plan should be included both functional and esthetic results according to orthogenatic surgical prognosthic factors.

This review study was conducted by searching the keywords "orthognathic surgery", "maxilla", "soft tissue" and "nose" in Medline library and Google scholar databases among the studies published between the years 2012 and 2021. Finally, 14 studies were selected and reviewed.

Review of the previous studies have shown that changes in the soft tissue of maxilla and nose occurred after almost all maxillary osteotomies. Widening of alar width (AW) and alteration of nasolabial angle (NLA) have been reported frequently. Common preventative methods such as Alar Cinch suture have had little effect on preventing these changes. Conversely, the occurrence of these alterations may improve the beauty of the face, which depends on the race and ethnicity of patients and the perception of the aesthetic standards among them.

Functional and aesthetic evaluation of the nasal soft tissue should be considered as a part of the diagnosis and treatment planning for orthognathic surgeries and also the strategies considering the management of these changes should be shared with patients. The effect of Alar cinch suture on the control of alar base changes is challenging and requires further study.

Impacted teeth are those with a delayed eruption time or that are not expected to erupt completely based on the clinical and radiographic assessment. It is a challenge for orthodontists. The treatment plan for each patient depends on his or her facial and dentoskeletal characteristics, cost and risks of treatment, patient's preference, and the orthodontist's experience .Mandibular canine impaction is regarded as a rare phenomenon. The aim of this study was to report the treatment of a case with unilateral impaction of the mandibular canine.

A 15-year-old girl presented with complaints of a non erupted canine in the right lower quadrant and anterior  irregular teeth.There was no significant medical history . On radiographic examination, the right lower permanent canine was impacted. Surgical exposure and orthodontic traction was performed and canine was brought satisfactorily to occlusion

Although, the incidence of mandibular canine impaction is very rare, but clinicians need to be familiar with its management and treatment techniques, so that it can be guided to a suitable place in the dental arch.