Journal of Dental Medicine

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Dental enamel is the end product of amelogenesis, which can be considered to take place in three interrelated phases. When this complex sequence of cytological and physicochemica! events disrupted by genetic or environmental factors, the function of the ameloblasts may be disrupted permanently or temporarily. The result shows qualitative and quantitative defects that may range from a complete absence of enamel or a slight discoloration. The aim of this study was to determine the prevalence of enamel defects by DDE index in a randomly selection group of 1637 students age 7-12 years old in Isfahan (0.2-0.3 PPMF"). Enamel defects were present on one or more teeth in 27% of the cases. The most common affected tooth was the central maxillary and then first molar of maxilla. The most common affected surfaces were buccal. Hypoplastic defects were found in first molar however premolar and canine were affected by diffuse white lines opacity.

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Statement of Problem: Previous experiences and clinical observations indicate that enamel hypoplasia and hypocalcification of first permanent molars, among infants born in Cessarian Section Delivery (C/S) is more common than those born in Normal Vaginal Delivery (NVD). Moreover, the first permanent molar is the only tooth that its "cusp tip calcification" starts exactly at the time of delivery.

Purpose: The aim of this research was to investigate the relationship between delivery type and clinical feature of the first permanent molar. Meanwhile, the different effects of the elective and selective types of cessarian, on the clinical feature of first permanent molar, were studied.
Materials and Methods: Birth files, relation to the year 1994 and before, were extracted from a gynecologist clinic. One hundred patients with NVD, 50 patients with selective cessarian delivery and 50 patients with elective cessarian delivery were chosen to examine clinical feature of the first permanent molars of their children. The children, 6 years old or more, were examined. The medical information of the mother were extracted from her file and that of child, were asked from the mother. To analyze the result, X lest- was used.
Results: The prevalence of enamel defects (hypoplasia and hypocalcification) of the first permanent molar among children born by C/S, were significantly different from the children born by NVD (P=0.0002). Mean while, the prevalence of these enamel defects in the selective cessarian delivery was more than elective cessarian delivery (17% vs. 9%), which was not statistically significant (P-0.07)

Conclusion: It is suggested that gynecologists, pediatricians and pedodontists provide the parents with necessary information about the child's first permanent tooth and ask them to pay enough attention to keep this tooth which is considered as the key of occlusion.

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Statement of Problem: Regenerative periodontal procedures are one mode of therapy that attempts to restore the lost supporting structures of the dentition around a previously diseased root surface.
Purpose: The purpose of this study was comparison between Enamel matrix proteins (EMP) used alone or in combination with autogenous bone graft (ABG) in the treatment of human intrabony periodontal defects.
Materials and Methods: This clinical trial study, was done on 8 pairs of matched two wall intrabony periodontal defects with 5 mm or more probing depth and 3 mm or more depth of intrabony component following phase I therapy. In control sites Enamel matrix proteins (EMP) and in lest sites EMP with autogenous bone graft (ABG) was used.
Results: No differences were found in terms of oral hygiene and defect characteristics, at baseline. Six months after treatment, both procedures significantly improved the clinical probing depth and clinical attachment level. Although bone fill was significant for both groups but EMP+ABG significantly showed more bone fill and defect resolution (bone fill 2.75mm versus 3.67mm). Crestal resorption was the same for both groups and its difference was not significant.
Conclusion: The results of this study demonstrates that both procedures improves clinical parameters and combined use of EMP with autogenous bone graft will promote more bone fill and more defect resolution. A
difficulty in obtaining sufficient amounts of autogenous bone from intra oral sites is one of the limitations of
this procedure.

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Statement of Problem: Bleaching materials are able to change the surface morphology as well as mineral and organic content of tooth structure. Considering that bleaching is done for aesthetic purpose, awareness of the possible effect of these materials on hard tissue is important, because it may affect the restorative treatments.

Purpose: The aim of this study was comparing the effect of two bleaching materials, Kimia and Ultradent both containing 35% H2O2, on tooth enamel by SEM.

Materials and Methods: Five intact central incisors were cut into three sections vertically and each part was randomly divided into three groups. Group 1 (control), without any bleaching. Group 2, bleached with Kimia 35% H2O2. Group 3, bleached with Ultradent 35% H2O2. Each tooth served as its own control. Then the samples were observed by SEM with 250 and 500 magnifications.

Results: In the control group some scratches and small white grains were observed which seems to be the result of mastication trauma and pumice powder. In the other groups, morphologic changes like increased surface roughness, deepening of cracks, rod exposure and presence of new cracks were observed. The two experimental materials did not differ in these regards.

Conclusion: It seems that both studied materials have limited destructive effects on tooth enamel which seems to be of no clinical importance.

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Background and Aim: The bonding mechanisms of self etching primers, based upon the simultaneous etching and priming of dentin, simplifies the bonding technique, but the efficiency of these systems is still controversial. This study compared the shear bond strength of three self etch adhesive systems in dry and wet conditions.

Materials and Method: In this experimental study, 77 intact bovine lower incisors with flat 600 grit sanded enamel surface were fixed in acrylic molds and divided into 7 groups, of 11 teeth. The enamel surfaces were treated according to a special procedure as follows: Group 1: Prompt L-Pop (PLP) in dry condition, Group 2: Prompt L-Pop in wet condition, Group 3: Clearfield SE Bond (CSEB) in dry condition, Group 4: Clearfield SE Bond in wet condition, Group 5: iBond (iB) in dry condition, Group 6: iBond in wet condition, Group 7: Margin Bond (Control) in dry condition. Surfaces were air dried for ten seconds, or blot dried in wet condition. Composite resin was bonded on the enamel and built up by applying a cylindric teflon split mold (4 mm height 2mm diameter). After 24 hours storage in dionized water at room temperature, all specimens were thermocycled and shear bond test was employed by a universal testing machine (Instron) with a cross-head speed of 1mm/min. The shear bond strength was recorded in MPa and data were analyzed with ANOVA and Scheffe statistical tests. P<0.05 was considered as statistically significant. The mode of failure was examined under a stereomicroscope.

Results: 1- Shear bond strength of CSEB in dry condition (21.5 ± 4.8 MPa) was significantly higher than PLP and iB groups (p<0.0001). 2- Shear bond strength of iB and PLP groups in dry condition (9.60 ± 2.2, 9.49 ± 3 MPa) were significantly lower than CSEB and control (2.99 ± 5.1 MPa) (P<0.0001). 3- There was no significant difference between PLP and iB groups in dry condition (P=1). 4- Shear bond strength of CSEB in wet condition (21.8 ± 3 MPa) was significantly higher than PLP and iB groups (P=0.0). 5- Shear bond strength of CSEB (10.8 ± 3 MPa) and PLP (10.6 ± 4 MPa) in wet condition were significantly lower than CSEB and Control groups (P=0.0). 6- There was no significant difference between PLP and iB groups in wet condition (P=0.99). 7- Shear bond strength of the three adhesives had no significant difference in dry and wet conditions (PLP: P= 0.53, CSEB: P= 0.84, iB: P= 0.53). The mode of failure in two groups of PLP and two groups of iB was predominantly in the adhesive bond and in the two groups of CSEB, mixed failure (adhesive with cohesive in composite) was predominantly observed.

Conclusion: CSEB had higher while iB and PLP showed lower bond strength to ground enamel. The three self-etch adhesives in this study did not show technique sensitivity to wet and dry enamel.

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Background and Aim: Intrabony periodontal defects are important problems in periodontology and up to now several ways have been suggested for their treatment .Treatment with enamel matrix derivatives (EMD) has been shown to enhance periodontal regeneration. There is limited information available from clinical trials regarding the performance of EMD in the treatment of periodontal intrabony defects. This study was designed to compare the clinical and radiographic effects of EMD treatment to that of open flap debridment (OFD) for two and three walled intrabony defects.

Materials and Methods: 18 patients were included in this clinical trial which have 24 two and/ or three intrabony defects. Defects were randomly divided into two groups (test and control). Defects in test group were treated with flap surgery plus EMD and in control group with open flap debridment. At baseline and at 3 and 6 months follow up, clinical and radiographic measurements were performed. Data were analyzed using Greenhouse-Geisser test with p<0.05 as the limit of significance.

Results: At 3 and 6 months, mean probing pocket depth reduction was greater in the test group (EMD) (4.33 mm and 4.70 mm) compared to the OFD group (2.54 mm and 3.09 mm). Mean values for clinical attachment gain in the EMD group after 3 and 6 months were 4.29 mm and 4.98 mm, and in OFD group were 2.83 and 2.82 mm respectively. Radiographic bone gain measured by radiovisiography technique was greater in the EMD group compared to the OFD group (4.66 mm in EMD and 1.11 mm in OFD group after 3 months and 5.78 mm in EMD and 1.39 mm in OFD group after 6 months).

Conclusion: Based on the results of this study, treatment with flap surgery and EMD compared to open flap debridment, produced more favorable clinical improvements in two and three walled intrabony defects.

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Background and Aim: With the introduction of different bondable restorative materials in dentistry, various methods have been suggested to enhance the polymerization and shear bond strength of these materials. The aim of this study was to determine the effects of different methods of enamel conditioning on bond strength of orthodontic brackets and on the bracket/ adhesive failure mode.

Materials and Methods: In this experimental in vitro study, brackets were bonded to thirty-six bovine incisor teeth with different protocols according to the manufacturer's instructions as follows: Group 1: conventional multistep adhesive (n=12) Group 2: self-etching primer system (n=12) Group 3: acid+self-etching primer system (n=12). Specimens were loaded in a universal testing machine (Instron, Canton and Mass) and the mode of failure was recorded. Data were analyzed by ANOVA and Kruskall-Wallis tests with p<0.05 as the limit of significance.

Results: The mean shear bond strength was 11.7 ± 4.2, 10.5 ± 4.4, and 10.9 ± 4.8 MPa for group 1, 2, and 3 respectively. There was no significant difference in bond strength among the three groups (P=0.800). No significant difference was observed among the three groups with respect to residual adhesive on the enamel surfaces (P=0.554).

Conclusion: Based on the results of the present study, the use of self-etching primers may be an alternative to conventional phosphoric acid pre-treatment in orthodontic bonding.

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Background and Aim: Extensive and continuous consumption of acidic drinks is the main cause of enamel erosion in human teeth. The purpose of this study was to compare the erosive potential of two Iranian drinks with those of two imported ones.

Materials and Methods: Two Iranian drinks (Cola Zamzam and Orange Zamzam) and two imported ones (Pepsi and Miranda) were studied in this experimental invitro study. 120 intact premolar teeth, extracted for orthodontic reasons were divided into 3 equal groups (A, B and C). Each group was exposed to one of the drinks for exposure times of: A: 15 minutes, B: 45 minutes and C: 12 hours. Each group was divided into 4 subgroups (each containing 10 teeth), which were exposed to 20 ml of one of the 4 drinks. The exposed surface was the same in all samples (a 5 mm in diameter semi circular window). The amount of Ca++ ion (mg/ml) added to each drink at the end of exposure time was estimated by atomic absorption spectrophotometer.

Results: 2 way ANOVA showed that the drinks were significantly different with regard to released Calcium ion. Time had significant effect on erosive potential. The two mentioned factors had significant interaction (P<0.001). The most erosive effect was seen in 12 hours in all of the drinks. The erosive effect of Orange Zamzam in 15 minutes and Pepsi in 45 minutes and 12 hours was significantly more than other groups (P<0.001).

Conclusions: Pepsi had the most long term erosive effect among the four drinks, and Cola Zamzam had the least erosive potential.

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Amelogenesis imperfecta is an inherited disease that disturbs the formation of the enamel. It occurs as two main categories, hypomineralized and hypoplastic. Both deciduous and permanent teeth are affected, and the disorder may create unaesthetic appearance, dental sensitivity, and severe attrition. In this article through performing a structured literature review, numerous treatment modalities which so far advocated in rehabilitation of amelogenesis imperfecta in adults and children is discussed. The progressive changes on open bite, the problem of bonding during restorative phase of treatment , the rehabilitation difficulties of deciduous as well as permanent teeth is also discussed in detail and finally the interdisciplinary approach for treatment of this disability is demonstrated and some points for decision making in treatment protocols are suggested.

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Background and Aim: Black staining after taking iron drops on the primary teeth is always concern of parents. There is not an exact explanation for the mechanism of iron black staining. The purpose of this study was to compare tooth discolorations, atomic absorption and structural changes of primary teeth enamel caused by two kinds of iron drops[ Kharazmi(Iran) and Fer-in-sol(USA)].

Materials and Methods: In this ex-vivo study, 93 sound primary teeth in normal color range were divided into five groups. Two groups of samples were immersed into the Artificial Caries Challenge(ACC) for two weeks before getting exposured to iron drops: Group 1 Control(NS): sound enamel teeth which were kept in Normal Saline environment(NS)(13teeth). Group 2 (NS-KH): NS, kharazmi iron drop (20 teeth). Group 3 (ACC-KH): ACC, Kharazmi iron drop (20teeth). Group 4 (NS-F-in-S): NS, Fer-in-Sol iron drop (20teeth). Group 5 (ACC-F-in-S): ACC, Fer-in-Sol iron drop. Visual tooth discolorations were determined by a specialist in operative dentistry who was not aware of experimental groups. The iron concentration was measured by ICP system (Vista-pro, Australia) and the structural changes were studied by SEM (Philips, Netherland). The data of discoloration were studied with Kruskal-Wallis test and multiple comparison using Bonferroni type test, and with the data of atomic absorption were studied with oneway ANOVA test and Tukey HSD test.

Results: The discoloration in the teeth immersed into the ACC (ACC-KH, ACC-F-in-S) was more severe than the sound enamel surface (NS-KH, NS-F-IN-S) (p<0.001) and Kharazmi iron drop caused more discoloration in the teeth immersed into the ACC (p=0.018). The teeth immersed into the ACC, absorbed more iron than the sound enamel surface (p<0.001) and also the teeth immersed into the ACC absorbed more Kharazmi iron drop (p<0.001). In the Scanning Electron Microscopy study, at low magnification in the sound teeth the perikymata was arranged regular. At low magnification in the teeth immersed into the ACC, many fractures were observed. The fractures in group 3(ACC-KH) were more and deeper.

Conclusion: Being immersed into the ACC, caused more iron absorption, severe discoloration and structural changes in the enamel of primary teeth. Such changes were more distinct in the teeth exposed to Kharazmi iron drop than the teeth exposed to Fer-in-Sol iron drop.

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Background and Aims: Moisture contamination of etched enamel during application of sealant is the most frequently cited reason for sealant failure. In previous studies, some hydrophilic bonding agents have been shown to bond to etched enamel after salivary contamination. The purpose of this study was to evaluate the enamelsealant interface following the use of primer on the saliva contaminated and/or moist etched enamel.

Materials and Methods: 40 extracted human incisors were selected. The enamel surfaces were etched for 20 seconds with an acid gel and rinsed for 30 seconds and dried until chalky surface was observed. Teeth were randomly divided into four treatment groups (n=10). Sealant (Deguseal mineral, Degussa) was applied on (1) etched enamel surface as a standard control group, (2) in conjunction with using primer material on moist etched enamel, (3) in conjunction with using primer material on salivary contaminated etched enamel, and (4) on wet contaminated etched enamel surface as a negative control group. Then, the specimens were observed with scanning electron microscopy (SEM) at ×1400 magnification. To evaluate the enamel resin interface, the number of resin tags was counted. Data were analyzed using one-way ANOVA.

Results: The results showed that primer used on moist enamel under sealant had no significantly difference in number and shape of tags in comparison with standard group (P>0.05). Application of primer on saliva contaminated enamel surface under sealant significantly reduced the number of tags and changed the shape and pattern of tags (P<0.001). Following application of sealant on contaminated and etched enamel alone, no resin tags formed.

Conclusion: Application of primer relatively reduced sensitivity to saliva contamination but the pattern was changed and number of tags reduced. Therefore, primer application might be useful whenever the isolation is not possible. However, it should be emphasized that restrict isolation in sealant therapy is recommended.

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Background and Aims: Despite significant decline in dental caries in recent decades, the disease remains a public health problem especially in developing countries. In recent years combined application of laser and fluoride has been introduced as a new caries-preventive measure. The purpose of the present study was to review the literature on the preventive effect of combined application of laser and fluoride on the dental caries. Materials and Methods: PubMed, Google Scholar and EMBASE databases were searched for articles published from 1990 to November 30, 2013. Various combinations of the following keywords were used: Dental caries, Laser, Fluoride, Fluoride therapy, Prevention and Enamel. The inclusion criteria included all levels of available evidence. Articles published only in english language were evaluated, and unpublished data were not sought. Results: Several studies evaluating the effect of laser alone or combined with topical fluoride to prevent dental enamel demineralization were found. Studies assessing the combined effect were more frequently done on permanent teeth and just a few studies were done on primary teeth. In total, most of the studies confirmed that combined application of laser and topical fluoride has a remarkable effect in prevention of enamel demineralization compared to application of each of them alone. Conclusion: Laser irradiation combined with topical fluoride application seems to provide the best prevention effect on the dental caries initiation and progression in enamel of permanent teeth. However, more experimental and clinical studies are necessary to be done on the primary teeth in this area.