Journal of Dental Medicine

---

Facial prognathism, which is a problem in some orthodontic patients, is characterized by a number of cephalometric changes. Most clinicians use SNA angle in lateral cephalometric analysis to evaluate the amount of maxillary prognathism. Since SNA angle is not a reliable measurement for maxillary prognathism, and taking into account that the amount of prognathism changes in relation to cranial anatomy, according to Bjork it's better to measure the facial prognathism by the angle between anterior and posterior cranial base. According, two angles are recommended NSBa and NSAr.In this study 80 lateral cephalograms from three malocclusion groups, were studied and the amount of maxillary prognathism in relation to SNA and NSAr angles and their relationship to each other were measured.

The results were as follows:
1- Studying facial prognathism in relation to SNA and NSAr angles it was found that SNA angle is influenced by cranial base shape
2- The mean value of anterior and posterior cranial bases didn't show significant differences.
3- The mean value of SNA angle didn't show significant statistical difference in various malocclusion groups.
4- The correlation coefficient of ANB angle and wit's measurement is low.

---

Wear characteristics of dental amalgams were investigated by in vivo and in vitro tests. Wear of dental amalgam was studied and evaluated using a three - body abrasion test and Pin-On-Disk method. Porcelain was used for preparing disk and materials such as toothpaste, artificial saliva and naturally saliva were used as the third material that was contributed in tribologic system The results showed that effects of various toothpastes on the wear of dental amalgam are considerably different and size, shape and chemical composition of amalgam are important too.

---

In this study, by cluster simple random sampling, the prevalence of ectopic of first permanent molar in 8 years old Tehran school children is considered and determined as 0.87 percent The involvement of maxilla was more than mandible and the difference was significant. Bilateral involvement was more than unilateral and boys were more- than girls, how ever the differences were not significant. As for as the geographical distribution is considered, the differences were not noticeable, either.

---

Growth factors are biological mediators that have a key roll in proliferation, chemotaxy and differentiation by acting on specific receptors on the surface of cells and regulating events in wound healing.They can be considered hormones that are not released in to the blood stream but have one a local action. Some of these factors can regulate premature change in GO to Gl phase in cell devesion cycle and even may stimulate synthesis of DNA in suitable cells, Growth substances, primarily secreted by fibroblasts, endothelia! cells, macrophages and platelet, include platelet derived growth factor (PDGF), insulin like growth factor (IGF) transforming growth factor (TGF)a and (3 and bone morphogenetic proteins BMPs that approximately are the most important of them. (BMP)s could be used to control events during periodontal, craniofacial and implant wound healing through favoring bone formation According toLynch, combination of PGDF and IGF1 would be effective in promoting growth of all the components of the periodontium.The aim of this study was to characterize growth factor and review the literature to determine the mechanism of their function, classification and application in implant and periodontal treatment.

---

This investigation was performed according to the widespread application of base metal alloys and few articles published about the marginal integrity of restorations fabricated by these metals.Three standard dies of a maxillary first premolar were prepared with a flat shoulder finish line in buccal aspect and chamfer in palatal. One of them left with no change. On the buccal aspect of the second and third dies 135?and 1607 bevel were added respectively Using dual wax technique, nine wax patterns were formed on each die and casting procedure of selected non precious alloy was performed by centrifugal method. Marginal gaps of each copping seated on dies were measured by scanning electron microscope (SEM) with X500 magnification. Measurements were done on three areas of marked dies on buccal aspect. Measurement son palatal aspect was done on marked midpalatal point as control.Results and statistical analysis showed no significant difference among marginal gaps in lingual aspect.But on the buccal aspect there were statistically significant differences among the groups (P<0.001). Flat shoulder had the best marginal integrity (mean 4 micron). Shoulder with 160' bevel had the most marginal gap (mean 26.5 micron) and shoulder with 1357 bevel was between two other groups (mean 15.7 micron).

---

:.In the result of first world investigations, it has recommended that most oral and dental disease (over 80%) can be prevented by oral hygiene Instruction and sanitary methods.In our investigation, we have wanted to estimate the rate of knowledge, attitude and practice of dentists in urmieh. Our results exhibited that the rate of dentist's knowledge about sanitary and preventive methods and their etiologic relations of oral disease is 95%.But in spite of this high rate of knowledge the dentists attitude rate is %55.48 and more strange is that the practice of these dentist in relation with sanitary and preventive methods for patients has evaluated about 66.17% that ,this rate is 13% more than their attitude rate. The cause of this strange result, may be is dentists un honestly answer or because of their high theoretical knowledge of our dentist. May be we thinking that this recent factor in spite of insufficient attitude has effected on their practice.

---

The purpose of this survey was the determine of effectiveness of preventive precisures. 320 twelve years school student have chosen randomly. After determination of DMFT All of them divided to 4 groups. First group as control and the other groups were as oral hygiene education 6-fluoride therapy and sealant therapy group in a period of two years.Results of this study showed that fluoride therapy was more effective than the other procisures than oral hygiene instructions.

---

Odontoma is an odontogenic lesion with epithelial and mesenchymal origin and is composed of differentiated dental parts. Than because of abnormal organization of mature tissues. It seems that it is a hamartoma rather than real tumor. Odontoma is seen in two types of compound & complex.Out of 57 studied cases, 31 cases (54.2%) were of complex type 12 cases (21 %) were compound & 8 cases were of cystic. The age of incidence ranged from 5.5 to 68 years. The mean age in complex odontoma was 27 years & compound type was 19 years. There was no significant difference regarding the sex in the complex type. In compound odontoma women were affected 2 times more than means.Complex type are found in mandibular posterior era ereas more and compound type in anterior regions .In this studied found 12 cases impaction teeth.

---

Nucleolar organizer regions (NORs) are loops of rDNA, which in human, occur on the short arms of five acrocentric chromosomes, namely, 13, 14, 15, 21 and 22. NORs are usually demonstrated by binding If their associated proteins (NORAPsO to silver (Ag+) ions. The reaction is called AgNORs. It has been determined that, the number and the size of NORs is related to the proliferative activity and grade of malignancy. This has led to the application of AgNOR method to a wide range of diagnostic problem cases, including breast, salivary glands and lung malignant neoplasms.The purpose of this study was to determine the value of AgNOR method in assessment of the grade of malignancy in non- Hodgkin's lymphoma of head & neck, which often is difficult and essentially important in relation to the prognosis and treatment.41 cases of paraffin embedded specimens of NHL, which were classified by working formulation system,were selected and then AgNORs method was applied on them.AgNORs were enumerated for all 41 cases of NHL (Standard Crocker).The mean AgNORs in 11 cases of low grade 15 cases of intermediate grade and 15 cases of high grade NHL was 1.66 (SEM= 0.098), 2.25 (SEM= 0.084) and 5.19 (SEM= 0.11), respectively.In analysis of variance and multiple comparisons, a significant difference was found between the three groups of NHL (P<0.000I).It is concluded that the AgNORs, as a reliable method, could be used in differentiation of low,intermediate and high grade NHL in head and neck area.

---

During the human gestation period, various systemic alterations occur in the mother secondary to endocrine changes. These changes, combined with the presence of the gravid uterus, result in conditions affecting the various systems of the mother which must be considered by the dentist.Fetal development is divided into three stages:1) The fertilization and implantation period 2) The embryonic period and 3) The fetal period.The second period characterized by organogenesis which taratogens may result in functional and morphogenic malformations.The ideal dental treatment schedule for the pregnant patient is twice during first trimester, at least once during second trimester and once during third trimester.The second trimester is an ideal time for performing dental treatment.Emergency problem should be alleviated immediately during pregnancy.Indicated medications should not be with held because of pregnancy but patients must be informed of benefits and risks.With careful attention to the special needs of the pregnant patient, the dentist can provide high quality dental care while minimizing potential risks to mother and fetus.Emphasis should be on preventive strategies and meticulous oral hygiene to manage common oral problems associated with pregnancy.

---

The most important craniofacial dysostosis & syndromes are Crouzon, Apret, Pfeiffer.Carpenter Saether- Chotzen. The common characteristic is premature closure of cranial sutures, which result in Maxillofacial deformities. Perfect recognition and carefully evaluation are the most important points in their reconstruction surgery.Because the prevalence & surgical treatment of Crouzon syndrome is low, I present a case report include surgical treatment of a patient with crouzon which was a accomplished in Shariati Hospital.

---

This study is for appointment the dose of systemic 4 groups of patients selected for this study.First group had sealling, root planing and planing and periodontal surgery and no drugs. Second group had sealling, root planing and periodontal surgery with 1 gr per day of tetracycline for two weeks and third group for 3 weeks and fourth group for 4 weeks.The fourth group was.the best clinical improvement. The indexes were PPD, CAL, PI, GI.

---

Enuresis during childhood disturbs children both physically and emotionally. It reduces their self-confidence and so causes many personal and social problems.Different ways of treating this problem have been suggested and carried out, but none of them have been a total success. But one way is to change from mouth breathing to nose breathing.Enuresis in 6 Patient out often was totally cured and in three other patients who's mouth breathing all altered to mouth- nose breathing it was reduced, approximately to the extended of a half.One who's mouth breathing was not subject to any change enuresis was not remedied either.On the whole, it could be concluded that the conversion of mouth breathing to nose breathing would solve enuretic difficulties to a certain extend.

---

After approximately 40 years of experience in the field of resin - bonded restorations (R.B.R),these restorations arc one of the most controversial. During these years, many suggestions have been made for better performance and increasing durability of these restorations. The aims of this paper are:1 - Reviewing the literature for the so many factors involving the success or failure of R.B.R.2 - Introducing a new and simplified method for increasing the durability and /or relention of R.B.R.

---

Indirect esthetic restorations have recently gained popularity, and choosing suitable cement is an important concern in this regard. A wide variety of resin cements with different curing models:(chemical, light, dual), have been introduced to the profession, and among them the dual systems are claimed to be able to continue polymerization after stopping the light. In order to study and compare the polymerization process of different curing systems, this research was performed.The present study measured the degree of conversion (DC) of three types of resin cements: a self cured,a light cured and a dual cured cement. The samples were prepared as follows:1-The self cured samples were made according to the manufacturer.2-The light cured samples were exposed to the curing light for 60 seconds, through a 2 mm thick wafer
of porcelain.3- The dual cured samples were divided into 2 groups. The first was lighted similar to the light cured samples, and the second did not receive any light.The degree of polymerization was measured by FTIR at time levels of 5, 10,20,30,45,60 minutes and 24 hours post mixing. The infrared spectrum of the samples were recorded and degree of conversion were determined. The results demonstrated an increase in mean DC of all groups at post mixing time, but this was significant only in the lighted dual cured cement (PO.05). The light cure resin showed high DC at the base line time (5min). At the end of 60 minutes, the self cure resin had the most DC. The unlighted dual cement had a very low DC and didn't improve in polymerization during the post mixing controls.The lighted dual cement had a significant improve in curing at post mixing times, and it was significantly different from unlighted dual cement. So the dual cure cement needs to receive sufficient light energy to initiate the curing process and the chemical component of this cement could not improve the DC completely.After 24 hours migration of unpolymerized monomers, seams to decrease the DC at the surfaces and removing the most superficial layer, showed that the underlying parts, had improved DC. It seems that in order to be sure of what happens at the restoration-tooth interface, it is appropriate to use self cure cements with improved flow and film thickness.

---

The root trunk (RT) of molar teeth is important diagnostic parameter that has a key roll in diagnosis and treatment planning.The purpose of this study is presenting a normal index of RT in mandibular molar teeth in different buccal (B). distal (D), Lingual (Li) and mesial (M) entrances, and to compare them with each other.It is a case series study that 351 extracted molar teeth, after removal of soft tissue and debridement of calculus, evaluated with gauge (with accuracy 0.1 mm) According to our measurement:In maxilla: M-side: 3.88± 0.15 mm, B-side: 4.7± 1.7. D- side: 4.87± 0.13mm. So with P.value <0.05 M and D RT are longer than and M RT is shorter than D RT.In mandibule: B- side: 2.73± 0.11mm and L side: 4.03±- 0.13mm. So with P.value < 0.01 Li RT is longer than B RT.According to ochsenbine classification our studying teeth have medium to long RT. We prescribe for educating the crater therapy in periodontal surgery the emphasize must be focused on craters with medium and long RT.The shortness of RT in B-side of lower molars needed the most attention during osteoctomy in resective procedures. Because RT not depended to underlying factors such as age, social and economic situation,and for large amount of sample size in our study, the result could be extended in Tehran.

---

One of the major goals of periradicular surgery is to create a good apical sea! at the apex. This is done by sectioning of 2 to 3mm from the apex, preparation of a class I cavity and filling with a biocompatible material.The purpose of this in vitro study was to determine whether ultrasonic units used for root end preparations could change the surface & structure of resected root ends, as competed to common methods of retropreparation. Eighty-five extracted single rooted teeth were divided into five similar groups. Then instrumented and filled with lateral condensation method. Then three millimeter of apex was resected, retropreparaiions in two groups were done with low speed handpiece and round V) ^ur and cavities in two other groups prepared with the highest power of dentspiay ultrasonic unit with TFI-10 tip and in one other group prepared with the highest power of neo sonic ultrasonic unit with diamond coated CT-1 retro tip.Following root resection and retropreparation the surface of resected root ends were examined for the presence of any cracks or structural changes on the surface of resected root ends with stereo microscope 50x.The results of this study showed thai high power settings of ultrasonic units can increase the potential of crack formation on resected root surfaces. In conclusion it is better to use low power setting of ultrasonic for retropreparation.

---

Frequently, diagnosis of lichen planus as a relative common chronic inflammatory mucocutaneous disease, is difficult, therefor, direct Immunofluorescence (DIF) examination is recommended for definite diagnosis. In this study both an statistical analysis of files of oral and maxillofacial pathology department of Dentistry school and direct immunofluorescence examination using paraffin blocks with new method, were performed. According to analysis of 8026 cases, 262 (3.26%) cases were diagnosed as lichen planus most patients were in fourth decade of their life and most common affected region was buccal mucosa, (69.68%).
In direct immunofluorescence study of 14 cases (using firth's method) fibrinogen deposits in 6 cases and immunostaining of colloid bodies with various immunoglobulins (IgA, IgG, IgM), C3 and also fibrinogen (few values) in most of patients, were detected. In spite of the fact that density of staining was lower than routine method (using fresh-frozen tissue), except for fibrinogen immunostaining, these findings are compatible with previous studies. In spile of limitation of samples, this study suggests that using this technique needs more evaluation and this can be used for diagnosis purposes when fresh-frozen tissue is unavailable.

---

---

Numerous techniques are used for treatment of tempromandibular disorder (TMD). Two aims should be considered when managing patients with TMD.a) pain reduction, feeling of improvement, prevention of untoward sequel of TMD.b) Complete cure and enabling the patients to continue a normal life as much as possible. For an exact and successful treatment the following certain rules should be followed:1} The physician's competence and knowledge in anatomy, physiology, psychology of the disorder.2) Pay attention to patient's statement and being sympathetic, developing rapport, performing a complete and careful clinical examination.3) Considering the patient's psychological or physiological deficits.4) Eliminating TMD Precipitating factor.In general, treatment of this disease like other disease of bones and muscles should not be addressed aggressively such as surgery or occlusion therapy. Simple and conservative methods should be applied for treating this disorder, as some cases are self-limiting and require no intervention.