Application of Laser Irradiation for Restorative Treatments.

Nowadays, lasers are widely used in many fields of medicine. Also, they can be applied at many branches of dental practice such as diagnosis, preventive procedures, restorative treatments, and endodontic therapies. Procedures like caries removal, re-mineralization, and vital pulp therapy are the most noticeable effects of laser irradiation which has gained much attention among clinicians. With controlled and appropriate wavelength, they can help stimulating dentinogenesis, controlling pulpal hemorrhage, sterilization, healing of collagenic proteins, formation of a fibrous matrix, and inducing hard tissue barrier. Nevertheless, there are many controversies in literatures regarding their effects on the quality of bonded restorations. It hampered a wide application of lasers in some aspects of restorative dentistry and requirements to identify the best way to use this technology. The aim of this mini review is to explain special characteristics of laser therapy and to introduce the possible applications of laser devices for dental purposes.

Is acupuncturing effective in controlling the gag reflex during dental procedures? A review of literature.

Traditional acupuncture has been introduced more than 2500 years ago which provides an alternative and complementary option during clinical practices. Its main mechanism is based on stimulating the nerves by altering the processes and perception of pain transmitters. It facilitates releasing natural pain relievers such as endorphins and serotonin. Its success for various dental procedures has been proved earlier. However, its effects on controlling the gag reflex seem to be overlooked. The gag reflex is recognized as a protective reaction for stopping the entrance of any foreign bodies into the oropharynx. Pronounced gag reflexes can have negative impacts on the quality of dental procedures. Many techniques have been suggested for managing this reflex and acupuncturing is one of those which seems to be overlooked recently. The aim of this paper is reviewing the published high-quality researches about the efficacy of this technique for eliminating the gag reflex during dental procedures.

Effect of different bleaching regimens on the flexural strength of hybrid composite resin.

BACKGROUND: The entire effects of different bleaching regimens on the mechanical properties of composite resins have remained unknown. The purpose of this study was to evaluate the effects of different bleaching regimens on the flexural strength (FS) of hybrid composite resins. MATERIALS AND METHODS: In this in vitro study, 80 bar-shaped specimens of hybrid composite resins were fabricated and randomly divided into four groups, 20 specimens in each group. First group (C) was considered as control. The other groups were treated by home bleaching (HB) agent, in-office bleaching (IB) agent, and the combination regimens (HIB), respectively. The FS was evaluated by three-point bending test by using a Universal Testing Machine. All data were analyzed by using Statistical Package for the Social Sciences (SPSS) software version 18, analysis of variance (ANOVA), and Turkey's post hoc statistical tests (α = 0.05). RESULTS: The maximum mean value of FS was seen in HB group with significant differences to other groups (P < 0.05). Also, the minimum FS was observed in group HIB. CONCLUSION: Application of different bleaching regimens does not have any adverse effect on the FS of hybrid composite resins. However, the administration of HB regimens seemed to have lesser negative impact on the FS.

Irreversible pulpitis and achieving profound anesthesia: Complexities and managements.

Dental pain management is one of the most critical aspects of modern dentistry. Irreversible pulpitis and further root canal therapy might cause an untolerated pain to the patients. The improvements in anesthetic agents and techniques were one of the advantages of studying nerve biology and stimulation. This article tried to overview of the nerve activities in inflammatory environments or induced pain. Furthermore, the proper advises, and supplementary techniques were reviewed for better pain management of irreversible pulpitis.

Clinical and radiological evaluation of implants placed with osteotome sinus lift technique: 19-month follow-up.

AIMS: Implant placement in the posterior region of the maxilla might be problematic due to poor regional bone quality. The aim of this study was to clinically and radiologically evaluate implants which were placed in the posterior region of the maxilla (with insufficient bone height) with osteotome sinus lift technique after 19-month follow-up. MATERIALS AND METHODS: Twenty-four patients with posterior maxillary alveolar height ranging from 5 to 8 mm were chosen for this prospective study. After breaking of the cortical bony sinus floor, sufficient bone substitute was placed, and sinus floor was elevated. In this way, a new sinus floor was created, which was designated for further implants placement. Fifty implants were placed immediately after osteotomy sinus lift technique. The mean clinical and radiological follow-up period was 19 months (with a range of 14-24 months). Success factors such as the absence of mobility, pain, infection, and the amount of crestal bone loss were determined in this study. For data analyzing, Kruskal-Wallis and Mann-Whitney tests were used. RESULTS: After 19 months, results showed 96% success rate. Two out of fifty implants failed due to mobility. The mean depth of implants in sinus, mean height of residual crestal bone before surgery, and the mean rate of crestal bone loss were 3.8, 7.9, and 0.71 mm, respectively. CONCLUSION: Osteotome sinus lift technique is a noninvasive surgical method for enhancing a desired length. Furthermore, implants insertion was successful after osteotome sinus lift technique in cases with insufficient bone height.

Comparing the Marginal Adaptation of Cold Ceramic and Mineral Trioxide Aggregate by Means of Scanning Electron Microscope: An In vitro Study.

BACKGROUND: Long-term success of endodontic surgeries is often influenced by the type of root-end filling material (RFM). The aim of present study was to compare the marginal adaptation of two different RFM, cold ceramic (CC) and mineral trioxide aggregate (MTA), using scanning electron microscope (SEM). MATERIALS AND METHODS: About 20 extracted human single-rooted teeth were collected and stored into sodium hypochlorite 5.25%. The teeth were decronated from the cemento-enamel junction to prepare 16 mm roots. The working length was measured, and 1/3 coronal of the canal was prepared by Gates-Glidden drills. Apical flaring was followed by K file size # 40-70 based on step back technique. After filling of the canals, 3 mm above the apex was cut at 90° to the long axis. Furthermore, 3 mm of the filling was removed from the apical part using the ultrasonic device. All of the prepared specimens were divided into two groups and were retro filled by MTA and CC. The roots were cut horizontally from 1 mm above the apical part, and dentin-filling material interface was observed by SEM. Finally, the collected data were analyzed by Mann-Whitney test and using SPSS software version 18 at a significant level of 0.05. RESULTS: The mean interfacial adaptation was higher in CC group. However, no significant differences were observed by statistical test (P = 0.35). CONCLUSION: Both CC and MTA had similar marginal adaptation as RFM however in vivo studies are recommended for better determination.

Microhardness Properties of Mineral Trioxide Aggregate and Calcium-enriched Mixture Cement Plugs at Different Setting Conditions.

BACKGROUND: Providing an apical stop in open apex roots is one of the endodontic challenges. The aim of present study was to compare the surface hardness of both mineral trioxide aggregate (MTA) and calcium-enriched mixture (CEM) cement at different setting situations. MATERIALS AND METHODS: A total of 40 freshly extracted human teeth with a single root and normal apex and no obvious caries or curvatures were selected. The teeth were sectioned horizontally from the cement enamel junction and 2 mm above the apex. Standard technique was administered for cleaning and shaping of the canals. Open apex root canal was prepared by using Peso reamer. The prepared teeth were randomly divided into four groups in which two groups were filled by MTA and the other groups were filled by CEM. White MTA and CEM cement plugs were prepared and condensed up to the apical end. In two groups, moistened paper point was placed in the canals and in the other group dried paper points was used. Vickers test was done to evaluate the microhardness and the collected data were analyzed by Kruskal-Wallis and three-way ANOVA tests using SPSS software version 18 at a significant level of 0.05. RESULTS: The highest and lowest surface hardness was observed in CEM group at dried condition with 4 mm thickness indentation (145.10 ± 7.60 kg/mm(2)) and moist MTA group indented at 8 mm thickness (111.25 ± 5.37 kg/mm(2)). However, no significant difference was noticed (P > 0.05). CONCLUSION: Humidity condition might not influence the microhardness properties of both MTA and CEM cement apical plugs at different tested indentation thickness.

Temporomandibular Joint Hypermobility Manifestation Based on Clinical Observations.

BACKGROUND: Joint range of motion might affected by some factors like laxity and increase joint mobility. Generalized joint hypermobility and temporomandibular joint hypermobility (TMJH) are reported as risk factors for temporomandibular disorders. The aim of this study was to survey the etiological factors of TMJH and its relations to habitual status. MATERIALS AND METHODS: In this cross-sectional descriptive study, 69 patients with TMJH were involved. After profiling personal information and medical history, the patients were divided into three groups based on their maximum mouth opening (MMO) as follow: (Light) MMO of 50-55 mm, (moderate): MMO between 55 and 65 mm, (severe) MMO >65 mm. For subjective observations, patients were asked to fill the prepared questionnaire. The objective evaluations conducted by a specialist. Finally, all the data subjected Chi-Square test by using SPSS software version 22 at a significant level of 0.05. RESULTS: TMJH was more common in women (74.2%). The light group had significant differences with other groups in the discomfort of TMJ and TMJ sound (P < 0.05). Furthermore, sever group manifested highest percentage of masticatory pains, significantly (P < 0.05). CONCLUSION: It can be concluded that pain in TMJ would have a correlation with MMO.

Effects of Thermal and Mechanical Load Cycling on the Dentin Microtensile Bond Strength of Single Bond-2.

BACKGROUND: Different studies have shown the uncertain effects of thermal cycling (TC) and mechanical load cycling (MC) on the dentin microtensile bond strength (µTBS) of composites. This study designed to investigate the effects of TC and MC on the dentin µTBS of single bond-2. MATERIALS AND METHODS: Flat dentinal surface was prepared on 48 sound extracted human third molar teeth, and were bonded by single bond-2 adhesive and Z250 resin composite. The teeth were randomly divided into eight equal groups, according to the thermal/mechanical protocol. TC and MC were proceeded at 5-55°C and 90 N with 0.5 Hz. Then restorations were sectioned to shape the hour-glass form and subjected to µTBS testing at a speed of 0.5 mm/min. To evaluate the bonding failure, the specimens were observed under the scanning electron microscope. The results were statistically analyzed with analysis of variance, t-test, Tukey HSD and post-hoc by using SPSS software version 17 at a significant level of 0.05. RESULTS: µTBS of all groups were significantly lower than the control group (P < 0.001). Adhesive failure was predominant in all groups and increased with TC and MC. CONCLUSIONS: TC and MC had an adverse effect on µTBS of the tested adhesive resin to dentin.

A Mini-review on the Effect of Mini-implants on Contemporary Orthodontic Science.

The purpose of this literature review was to screen the valuable published articles regarding to the impacts of mini-implants on orthodontic science, briefly. The searching category was performed on the Pubmed using MeSH words such as "dental (mini) implants, orthodontic anchorage procedures, and orthodontic appliances." After preliminary sketch, they were grouped as follow: Those evaluating (a) common appliances for providing orthodontic anchorage, (b) biomechanical details of mini-implants and their insertion, (c) clinical application of mini-implants for orthognathic treatments, (d) limitations and possible complications. In conclusion, mini-implant evolved the orthodontic treatment plans and compromised the required orthognathic surgery. Malocclusion treatment and pure orthodontic or orthopedic movements in the three-dimensions have become recently possible by using mini-implant to provide skeletal anchorage.

Histological assessment of pulpal responses to resin modified glass ionomer cements in human teeth.

BACKGROUND: The biocompatibility of resin-modified glass ionomers (RMGIs) as a lining material is still under question. The present study evaluated the response of the pulp-dentin complex following application of resin-modified glass-ionomer cement, calcium hydroxide and conventional glass-ionomer in deep cavities prepared in human teeth. MATERIALS AND METHODS: In this controlled clinical trial, 30 deep class V buccal cavities (3 mm × 2 mm × 2 mm) were prepared in human premolars treatment planned to be extracted for orthodontic reasons and divided into 3 groups. Groups were lined by a RMGI (Vivaglass), conventional glass Ionomer (Ionocid) and calcium hydroxide respectively. The cavities were subsequently filled with amalgam. Each group was then divided into two sub-groups according to time intervals 5 and 30 days. The patients were referred to Kerman Dental School and in accordance with orthodontic treatment plan; premolars were extracted and then prepared for histological assessment. The sections were stained with hematoxylin and eosin and periodic acid Schiff techniques. All of the samples were examined using a number of criteria including odontoblastic changes, inflammatory cells response, reactionary dentin formation and presence of microorganisms. The data were analyzed by Kruskal-Wallis and Mann-Whitney tests. P < 0.05 was considered as significant. RESULTS: There was no significant difference among odontoblastic changes, reactionary dentin, presence of bacteria and inflammatory cells response of the groups (P > 0.05). CONCLUSION: Ionocid and Vivaglass resin-modified glass ionomers can be used as lining materials in human teeth.

The effect of spraying different disinfectants on condensational silicone impressions; an in vitro study.

BACKGROUND: Dentistry equipment are exposed to different types of pathogenic microorganisms. The aim of this study was to investigate the effect of spraying three different types of disinfectants on condensational silicones after 5 and 10 min. MATERIALS AND METHODS: Totally, 66 circular samples of condensational silicone impression materials of 1 cm diameter and 2 mm thickness were contaminated by Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans fungus. Except for control samples, all of them were disinfected with sodium hypochlorite (NaOCl) 0.525%, Deconex and Epimax by spraying method. Afterward, they kept in plastic bags with humid rolled cotton for 5 and 10 min. In order to isolate microbiotas, the samples were immersed in 2% trypsin for 1 h and diluted with normal saline in a portion of 1, 1/2, and 1/4. The trypsin suspensions were transferred to culture plates for incubation and colony-forming unit assay. The data were analyzed by Mann-Whitney test and SPSS software version 16 at a significant level of 0.05. RESULTS: There was a meaningful difference between disinfection effects of Epimax-Deconex for all mentioned microorganisms after 5 min (P = 0.034), and between disinfection effects of NaOCl 0.525%-Epimax for S. aureus (P = 0.043) and P. aeruginosa (P = 0.046) after 5 min. Furthermore, there was a meaningful difference between disinfection effects of Epimax-Deconex (P = 0.034) and NaOCl 0.525%-Epimax (P = 0.034) for P. aeruginosa after 10 min. CONCLUSION: Condensational silicone can be effectively disinfected by spraying tested three disinfecting agents. More specifically, Deconex showed the best results compared to the other agents.

Histologic evaluation of apical pulp of immature apex following extraction, surface treatment, and replantation in different storage media in dogs.

AIM: This study was designed to evaluate the apical pulp of open apex teeth following extraction, surface treatment, and preservation in different storage media in dogs. MATERIALS AND METHODS: Four healthy male dogs were included in this prospective animal study. In the first phase of extraction, 30 teeth were extracted atraumatically from dogs (incisors and premolars) and then randomly divided into three groups based on different types of storage media: (i) milk, (ii) HBSS, and (iii) dry storage. In milk and HBSS groups, teeth were contaminated by dog's saliva and then kept in milk and HBSS solution, respectively, for 2 h. In the third group, teeth were stored in a dry storage for 2 h. Before replantation, all teeth were soaked in 10% doxycycline. After 2 months, in the second phase of extraction, all experimental teeth were extracted (40 teeth including control group). Three longitudinal sections (3-4 mm thickness) were stained with H&E and investigated under optical microscope. Histologic evaluations were performed, and data were analyzed using Kruskal-Wallis and Fisher's exact test (α = 0.05). RESULTS: There was a significant difference between the milk and control groups regarding the presence of the odontoblastic layer and resorption (P = 0.04). Also, there was a significant difference between dry storage and control group in the presence of the odontoblastic layer (P = 0.02). There was no statistically significant difference in other histologic factors between different groups (P > 0.05). It was revealed that there is no significant difference between different groups regarding the intensity (P = 0.06) and the type of the inflammation (P = 0.24). Also, the hyperemia showed no significant difference between different groups (P = 0.51). CONCLUSION: It was concluded that HBSS and milk are appropriate storage media. Also, it was shown that 2 h dry storage probably does not threaten the vitality of the pulp cells.

Effect of surface treatments on fracture resistance of root filled teeth with bonded fibre posts.

BACKGROUND/AIM: This study examined the effect of several dentin surface treatments on fracture resistance of root filled teeth containing bonded fibre posts. MATERIAL AND METHODS: The roots of 84 single-canal premolars were instrumented, filled with gutta-percha and randomly divided into seven groups. The coronal 9 mm of gutta-percha was removed to create a post space. In the experimental groups, canals were irrigated with distilled water, 37% phosphoric acid, 5% sodium hypochlorite, 17% EDTA, 5% sodium hypochlorite followed by 17% EDTA or 5% sodium hypochlorite followed by 10% ascorbic acid. Fibre posts were cemented using Panavia F2.0 resin cement, and the specimens were mounted in acrylic resin blocks. Following 1-week storage in an incubator, specimens were thermocycled and their fracture resistance was determined using a universal testing machine. Data were analysed using the Kruskal-Wallis test. RESULTS: Mean fracture resistance values ranged from 465.8 N in specimens treated with sodium hypochlorite and ascorbic acid to 739.1 N for those treated with sodium hypochlorite only. However, differences in fracture resistance were not statistically significant (P = 0.114). CONCLUSIONS: None of the surface treatments improved vertical fracture resistance of root filled teeth containing bonded fibre posts.

The effect of eugenol-free temporary cement's remnants on retention of full metal crowns: comparative study.

INTRODUCTION: The aim of this study was to evaluate the effects of eugenol-free temporary cement's remnants on the retentive strength of full metal crowns luted via zinc phosphate and resin cement (Maxcem) to the tooth structure. MATERIALS AND METHODS: Forty complete standardized Ni-Cr crowns in four groups were cemented by two types of permanent cements: zinc phosphate cement and resin cement (Maxcem). In the two groups before permanent cementation of crowns, temporary acrylic crowns were cemented by eugenol-free temporary cement. Crowns' retention was evaluated by Universal testing machine. All data were analyzed by means of one-way ANOVA test in SPSS software version 11.5 (α=0.05). RESULTS: There was no significant difference in groups with prior using eugenol-free temporary cement and groups with just using two permanents cement (p-value≥0.05). DISCUSSION: The application of temporary cement before permanent cementation of full metal crowns does not have any adverse effect on retention of full metal crowns, when temporary cements are removed properly.

Risk of Contamination of Different Areas of Dentist's Face During Dental Practices.

BACKGROUND: Dental practice presents opportunities for cross-contamination. The dentist's face is at high-risk of infection transmission. The purpose of this study was to evaluate the risk of contamination in different areas of dentist's face during dental practices. METHODS: The visible splashes of materials that accumulated on cellulose face shields during 144 prosthetics and periodontal procedures were evaluated. The splashes were detected on 14 areas (each 1 cm(2)) of the dentist's face including around nose, mouth, eyes, and zygoma by a magnifier (×2). One way Analysis of variance, Duncan and t-test were used for data analysis (α = 0.05). RESULTS: Contamination of different areas of dentist's face was significantly different (P < 0.05). The areas around nose and the inner corner of eyes were the most contaminated areas. Zygoma was the least contaminated area. The contaminated areas during periodontal treatments were significantly more than prosthetic treatments (P < 0.05). There was no significant difference between contamination on left and right sides of the face. CONCLUSIONS: During dental practice, central areas of the face such as inner part of the eyes and around the nose were most contaminated areas. These parts are the important areas for transmission of infection. It is recommended to use protective means like glasses, mask, and protective shield, which have more protection field in these areas.

Effect of base metal alloys recasting on marginal integrity of castable crowns.

INTRODUCTION: Base metals have a wide use in casting methods. Sometimes they are reused in laboratories which may have an adverse effect on the restoration marginal integrity. This study aimed to investigate the effect of recasting of alloys on marginal integrity of restorations. MATERIALS AND METHODS: Models with two types of finishing lines shoulder bevel 45° and shoulder 135° were produced and 15 wax copings were formed on each one of them. Each group containing 15 copings was divided into three subgroups A, B and C. Group A was casted with 100% new alloy, group B with 50% new and 50% recasted alloy and group C with 100% recasted alloy. Obtained metal copings were placed on dies and marginal gap size between restoration margin and the dies finishing line was measured using metric microscope and Moticam camera in four points, buccal, lingual, mesial and distal. RESULTS: A significant difference in mean marginal gap size exists among three types of alloys used (p-value = 0.036). A significant difference is observed between mean marginal gap size of two types of finishing lines for different alloys (p-value = 0.001). CONCLUSION: Using 100% recasted alloy is not recommended for any of the two types of finishing lines.

Magnet-retained facial prosthesis combined with maxillary obturator.

Prosthetic rehabilitation of the midfacial defects has always perplexed prosthodontists. These defects lead to functional and esthetic deficiencies. The purpose of this clinical case report was the presentation of the prosthetic rehabilitation of an extraoral-intraoral defect using two-piece prosthesis magnetically connected. This prosthesis has dramatically improved the patient's speech, mastication, swallowing, and esthetic.

Prevalence of clinical findings of carpal tunnel syndrome in Isfahanian dentists.

BACKGROUND: Carpal tunnel Syndrome (CTS) is the most common compression neuropathy. Jobs with frequent and repetitive hand movements are one of the risk factors for this syndrome. The aim of this study was to determine the prevalence of CTS in Isfahanian dentists. MATERIALS AND METHODS: In this cross-sectional descriptive study, 240 dentists were evaluated for CTS. Diagnosis was made according to both questionnaire and clinical tests of Phalen and Tinel. Age, sex, years of experience, working hours per week and the type of procedure were considered as dependent variables. All data were analyzed by Chi-square and T-test using SPSS software 11.5 (α=0.05). RESULTS: Among the dentists who were studied, 173 (72%) were male and 67 (28%) were female. 16.2% of males and 17.9% of females had symptoms of CTS and there wasn't any significant difference between them (P>0.05%). the prevalence increased with advancing age. In a way that it reached to 22.2% in ages more than 55 in contrast to 6% among individuals between 25-34 years old. With increasing of experience to 15 years the risk of CTS increased but an unexpected reduction was observed with more than 15 years of experience. CONCLUSION: This study showed the prevalence of CTS was 16.7% among dentists and was more common in older dentists. CTS prevalence was increased with age. The dentist population with more working hours per week and more experience years were more susceptible for this syndrome. Using suitable gloves, wrist splints and short periods of resting during vigorous continuous working can decrease the symptoms of this disease.

The effect of nanoclay filler loading on the flexural strength of fiber-reinforced composites.

BACKGROUND: Flexural strength of prosthesis made with dental composite resin materials plays an important role in their survival. The aim of this study was investigating the effect of nanoclay fillers and Poly (methyl methacrylate)-grafted (PMMA-grafted) nanoclay fillers loading on the flexural strength of fiber-reinforced composites (FRCs). MATERIALS AND METHODS: Standard FRC bars (2 × 2 × 25 mm) for flexural strength testing were prepared with E-glass fibers and a synthetic resin loaded with different quantities of unmodified nanoclay and PMMA-grafted nanoclay filler particles (0% as control group, 0.2%, 0.5%, 1%, 2%, 5%). Flexural strength and flexural modulus were determined. The data were analyzed using 2-way, 1-way ANOVA and post hoc Tukey's test (α = 0.05). The fracture surfaces were evaluated by Scanning Electron Microscopy. RESULTS: For groups with the same concentration of nanoparticles, PMMA-grafted filler-loaded group showed significantly higher flexural strength, except for 0.2% wt. For groups that contain PMMA-grafted nanoclay fillers, the 2% wt had the highest flexural strength value with significant difference to other subgroups. 1% wt and 2% wt showed significantly higher values compared to control (P < 0.05). None of the unmodified nanoclay particles loaded group represented statistically higher values of flexural strength compared to control group (P > 0.05). Flexural modulus of 2%, 5% wt PMMA-grafted and 0.5%, 1%, 2%, 5% wt unmodified nanoclay particles-loaded subgroups decreased significantly compared to control group (P < 0.05). CONCLUSIONS: PMMA-grafted nanoclay filler loading may enhance the flexural strength of FRCs. Addition of unmodified nanoparticles cannot significantly improve the flexural strength of FRCs. Addition of both unmodified and PMMA-grafted nanoclay particles in some concentrations decreased the flexural modulus.