Hussain QA, Awan KH. Effect on Quality of Life in Oral Cancer Patients after Radiation and Chemotherapy. J Contemp Dent Pract 2016;17(2):97-98.

Thermoplastic resin polymers are widely used in medicine due to their biostability and hypoallergenic properties, making them a possible alternative to poly-methylmethacrylate (PMMA). The current research examined the microstructure of a rapid injection molding system thermoplastic resin for construction of flexible denture compared with that of heatcured PMMA.

A total of 40 disk-shaped specimens (25 mm in diameter and 3 mm in thickness) were prepared and divided into two groups of 20 disks each (group I samples were of thermoplastic acrylic resin while group II was heat-cured PMMA resin).

In group I, thermogravimetric analyzer showed that increasing the temperature up to 169°C resulted in about 1.3% of the material loss, and after that the material remains thermally stable up to 200°C. Group II showed 2.24% weight loss at 171°C, and further weight loss (12.025%) was observed on heating to 230°C. Fourier transform infrared (FTIR) spectrophotometer analysis in the range of 400–4000 cm^-1 detected the presence of an amine group (N-H) in group I samples and the presence of methylene group attached to inorganic Si as reinforcement filler (Si-CH₃).

Thermoplastic resin displayed excellent thermal stability and the absence of residual monomer within the polymerized material, suggesting its suitability for the fabrication dentures.

Al-Dharrab A, Shinawi L. Thermogravimetric Characterization of the Microstructure Composition of Polyamide Injection Molded Denture Base Material vs Conventional Compression Molded Heat-cured Denture Base Material. J Contemp Dent Pract 2016;17(2):99-104.

The aim of this article was (i) to define the chemical constituents of Cinnamomum zeylanicum essential oil (CEO), (ii) to compare the antimicrobial activity of CEO with triple antibiotic paste (TAP) and calcium hydroxide [Ca(OH)₂] on planktonic and biofilm Enterococcus faecalis; and (iii) to compare the cytotoxicity of these medicaments on L929 fibroblasts.

Gas chromatography-mass spectrometry was used to define the constituents of CEO. Zone of inhibition, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill tests were performed. Further, 108 human teeth were infected with E. faecalis and treated with the medicaments for 1, 7, and 14 days. Cytotoxicity was assessed by exposing L929 fibroblasts to the medicaments.

Cinnamaldehyde was the main component of CEO. Triple antibiotic paste had the greatest zone of inhibition and the smallest MIC and MBC. Triple antibiotic paste and CEO eradicated planktonic E. faecalis after 4 and 24 hours, while Ca(OH)₂ failed to achieve 100% killing after 24 hours. Cinnamomum zeylanicum essential oil and TAP eradicated biofilm E. faecalis after 7 and 14 days, but Ca(OH)₂ could not eliminate E. faecalis after 14 days. Cinnamomum zeylanicum essential oil was the most biocompatible medicament.

Cinnamomum zeylanicum essential oil is an efficient antibacterial agent against planktonic and biofilm E. faecalis and it was cytocompatible to L929 fibroblasts. Therefore, CEO has the potential to be used as an antimicrobial agent in root canal treatment.

Abbaszadegan A, Dadolahi S, Gholami A, Moein MR, Hamedani S, Ghasemi Y, Abbott PV. Antimicrobial and Cytotoxic Activity of Cinnamomum zeylanicum, Calcium Hydroxide, and Triple Antibiotic Paste as Root Canal Dressing Materials. J Contemp Dent Pract 2016;17(2):105-113.

The purpose of this in vitro study was to evaluate the antimicrobial activity of 2% chlorhexidine gel (CHX) as auxiliary chemical substance and intracanal medications on Candida albicans, Candida albicans, Enterococcus faecalis, Escherichia coli, and their endotoxins in the root canals.

The study was conducted on 48 single-rooted human teeth divided into four groups (n = 12), according to intracanal medications used: (1) Calcium hydroxide + apyrogenic saline solution (Ca(OH)₂ + SS), (2) 20% ginger glycolic extract (GEN), (3) calcium hydroxide + 20% ginger glycolic extract (Ca(OH)₂ + GEN), (4) apyrogenic SS (control). Collections were made from the root canal content before preparation (baseline–S1), immediately after instrumentation (S2), 7 days after instrumentation (S3), after 14 days the action of intracanal medication (S4), and 7 days after removal of the intracanal medication (S5). The antimicrobial activity and endotoxin content were analyzed for all collections. The results were statistically analyzed by the Kruskal–Wallis and Dunn tests at a significance level of 5%.

After instrumentation with CHX, there was complete elimination of E. coli and C. albicans, except for E. faecalis, which was significantly reduced and then completely eliminated after intracanal medication. There was significant reduction of endotoxin after instrumentation. Comparison of collection after instrumentation and intracanal medication revealed reduction of endotoxins in all groups; this reduction was greater in group Ca(OH)₂ followed by the group GEN.

It was concluded that the instrumentation using CHX and intracanal medication used were able to eliminate the microorganisms from the root canal; the endotoxins were reduced, yet not completely eliminated.

This study is important and relevant for searching alternatives during endodontic therapy, since it aims to study the effect of Zingiber officinale on microorganisms and endotoxins present in root canals.

Valera MC, Oliveira SAC, Maekawa LE, Cardoso FGR, Chung A, Silva SFP, Carvalho CAT. Action of Chlorhexidine, Zingiber officinale, and Calcium Hydroxide on Candida albicans, Candida albicans, Enterococcus faecalis, Escherichia coli, and Endotoxin in the Root Canals. J Contemp Dent Pract 2016; 17(2):114-118.

To evaluate the push-out bond strength (BS) of direct anatomic posts (DAPs) and conventional fiber posts (CFPs) cemented with different luting agents in different thirds of flared root canals.

A total of 60 human single-rooted canine teeth were transversally sectioned 16 mm from the radicular apex. After endodontic treatment, canals were flared with diamond burs. Samples were divided into six groups according to post type and luting agent: DAP and RelyX U100 (RXU); DAP and RelyX ARC (RXA); DAP and RelyX Luting 2 (RXL); CFP and RXU; CFP and RXA; CFP and RXL. Roots were sectioned transversely into six 1-mm-thick slices. The push-out test was performed and failure modes were observed.

The DAP groups (7.23 ± 2.05) showed highest BS values (p < 0.05) when compared with CFP (5.93 ± 1.76). RelyX U100 (8.17 ± 1.70) showed higher BS values (p < 0.05) than RXA (6.46 ± 1.38), and RXL (5.10 ± 1.65) showed the lowest values. Bond strength on the apical third was statistically lower (p < 0.05) than that on the other thirds of the root canals. There was a predominance of adhesive failure for all groups.

The DAPs improved retention in flared root canals, and RXU was the most effective luting agent. The apical third showed the lowest BS values.

The relining procedure of fiber posts with composite and the proper selection of luting resin cement are important for increasing bonding effectiveness in flared root canals.

da Silveira-Pedrosa DM, Martins LRM, Sinhoreti MAC, Correr-Sobrinho L, Sousa-Neto MD, Costa ED Jr, de F Pedrosa-Filho C, de Carvalho JR Jr. Push-out Bond Strength of Glass Fiber Posts Cemented in Weakened Roots with Different Luting Agents. J Contemp Dent Pract 2016;17(2): 119-124.

Oral hygiene technique is an important factor in maintaining the health and comfort of hospitalized patients given the frequent presence of oral biofilm and pathogens brought on by mouth breathing. This is an important practice to assist patients in intensive care, in particular those who are intubated and under mechanical ventilation because the realization of oral hygiene reduces the patient's risk of complications and length of hospitalization. The objective of this research was to evaluate the oral health condition of patients hospitalized in an intensive care unit (ICU) and to clarify the importance of protocol standardization involving these patients’ buccal hygiene.

In this study, the sample consisted of 45 patients admitted to an ICU who were evaluated in relation to the oral biofilm score index.

The results indicated that there was no significant difference in the biofilm score associated with the genre (p = 0.091), age group (p = 0.549), or teething profile (p = 0.207). However, the biofilm score was greater in partial and fully edentulous patients when compared with dentulous patients.

Based on these results, it is recommended that care providers in ICUs complete the relevant oral health care training programs.

When in the ICU, suitable dental conduct following a protocol of prevention of oral biofilm can lead to earlier diagnosis and can prevent the spread of pathogenic microorganisms, particularly those that are systemic in patients with low immunity.

da Silva JL, de O El Kadre GD, Kudo GAH, Santiago JF Jr, Saraiva PP. Oral Health of Patients Hospitalized in the Intensive Care Unit. J Contemp Dent Pract 2016;17(2):125-129.

Anterior middle superior alveolar (AMSA) nerve block injection targets the anterior superior alveolar nerve and the middle superior alveolar nerve branches of the infraorbital nerve through nutrient canals. Therefore, the central incisor to the second premolar teeth of one quadrant can be anesthetized. The aim of the present study was to evaluate the efficacy of AMSA nerve block injection with 3% mepivacaine solution at three different injection sites.

In a double-blind crossover study, 47 volunteers participated and three AMSA nerve block injections of 3% mepivacaine solution without epinephrine were administered at the anterior, posterior, and the most common injection sites with a 1-week interval between injections. Anesthesia of the central incisor to the second premolar of the injected side was evaluated by using an electric pulp tester. The success of the injection was considered as lack of response to two consecutive 80 readings. The generalized estimating equation analytic tests were administered (α = 0.05).

The success rate of the AMSA nerve block injection ranged from 27.5–47.5% for the most common injection site and 22.5–42.5% for both the anterior and posterior injection sites.

Changing the injection site did not result in statistically significant improvements (p > 0.05).

Changing the injection site anteroposteriorly did not influence the success rate of the AMSA nerve block injection.

Shokraneh A, Farhadi N, Saatchi M, Navaei H, Yaghmaei M. Effect of Three Different Injection Sites on the Success of Anterior Middle Superior Alveolar Nerve Block with 3% Mepivacaine: A Randomized Controlled Trial. J Contemp Dent Pract 2016;17(2):130-135.

Radiopacity is a fundamental requisite to check marginal adaptation of restorations. Our objective was to assess the radiopacity of 28 brands of light-cured composite resins and compare their radiopacity with that of enamel, dentin, and aluminum of equivalent thickness.

Composite resin disks (0.2, 0.5, and 1 mm) were radiographed by the digital method, together with an aluminum penetrometer and a human tooth equivalent tooth section. The degree of radiopacity of each image was quantified using digital image processing. Wilcoxon nonparametric test was used for comparison of the mean thickness of each material.

All of the materials tested had an equal or greater radiopacity than that of aluminum of equivalent thickness. Similar results for enamel were found with the exception of Durafill, which was less radiopaque than enamel (p < 0.05). All the specimens were more radiopaque than dentin, except for P90 (which was equally radiopaque) and Durafill (which was less radiopaque). The thickness of the specimens may influence the similarity to the enamel's radiopacity. All of the composite resins comply with specification #27 of the American Dental Association. The radiopacity of Amelogen Plus, Aph, Brilhiante, Charisma, Concept Advanced, Evolux X, Exthet X, Inten S, Llis, Master Fill, Natural Look, Opallis, P60, Tetric, Tph, Z100, and Z250 was significantly higher than that of enamel (p < 0.05).

With these composites, it is possible to observe the boundaries between restoration and tooth structure, thus allowing clinicians to establish the presence of microleakage or restoration gap.

Suitable radiopacity is an essential requisite for good-quality esthetic restorative materials. We demonstrate that only some composites have the sufficient radiopacity to observe the boundaries between restoration and tooth structure, which is the main cause of restoration failure.

Raitz R, Moruzzi PD, Vieira G, Fenyo- Pereira M. Radiopacity of 28 Composite Resins for Teeth Restorations. J Contemp Dent Pract 2016;17(2):136-142.

Guided tissue regeneration (GTR) therapy has shown good results in the management of mandibular molar class II furcation defects. Advances in biomaterial sciences have developed alloplastic bone replacement graft materials and bioabsorbable GTR barrier membranes with good biologic response and handling properties. The aim of this study was to compare the attachment gain and the bone fill obtained with an alloplast [biphasic calcium phosphate (BCP) 60% hydroxyapatite (HA) and 40% beta tricalcium phosphate (β-TCP)] with and without a bioabsorbable GTR barrier [flowable poly (DL-lactide) (PLA) dissolved in N-methyl-2- pyrrolidone (NMP)] in the treatment of mandibular molar class II furcation defects.

A total of 20 class II furcation defects were treated in 16 patients with chronic periodontitis in a comparative study. Ten defects were treated with Camceram^® (BCP 60% HA and 40% – TCP) bone replacement graft material (group I) and 10 defects with a combination of Camceram^® bone replacement graft material with Atrisorb^® Freeflow™, bio-absorbable GTR barrier (flowable PLA dissolved in NMP) (group II). At baseline and at 6 months postsurgery, clinical parameters of vertical probing depth (PD) and horizontal probing depth (P-H), clinical attachment level (CAL), gingival recession (GR), and vertical depth of furcation defect (VDF) and horizontal depth of furcation defect (BP-H) were evaluated.

Statistical analysis was done with the Statistical Package for Social Sciences (SPSS) program. Intergroup comparisons made at 6 months postsurgery by unpaired Student's t-test showed mean reduction in PD in group I was 3.10 ± 0.73 mm and in group II was 3.20 ± 1.03 mm (p > 0.05). Mean reduction in P-H in group I was 1.60 ± 0.69 mm and in group II was 1.90 ± 0.73 mm (p > 0.05). Gain in CAL in group I was 2.80 ± 1.03 mm and in group II was 2.90 ± 0.94 mm (p > 0.05). Change in GR in group I was .0.30 ± 0.48 mm and in group II was .0.30 ± 0.48 (p > 0.05). Reduction in VDF in group I was 1.30 ± 0.67 mm and in group II was 1.80 ± 0.63 mm (p . 0.01). Reduction in BP-H in group I was 1.30 ± 0.67 mm and in group II was 1.90 ± 0.73 mm (p . 0.05).

It was concluded that the combination technique of BCP alloplast with a flowable bioabsorbable GTR barrier led to better results in regard to defect bone fill as compared with when the BCP alloplast alone was used.

Kini V, Nayak DG, Uppoor AS. A Clinical Evaluation of Biphasic Calcium Phosphate Alloplast with and without a Flowable Bioabsorbable Guided Tissue Regeneration Barrier in the Treatment of Mandibular Molar Class II Furcation Defects. J Contemp Dent Pract 2016;17(2):143-148.

This study evaluated the influence of a silane-coupling agent on the bond strength of a self-adhesive cement and a conventional resin cement to a lithium disilicate glass ceramic.

A total of eight ceramic blocks were fabricated and divided into four groups (n = 2). In groups 1 and 3, ceramic surfaces were etched with hydrofluoric acid 10% for 20 seconds, rinsed for 30 seconds, and air-dried. One layer of a silane agent was applied onto all ceramic specimens and air-dried for 30 seconds. In groups 2 and 4, ceramic surfaces were etched with hydrofluoric acid, rinsed, and air-dried without application of the silane-coupling agent. The ceramic blocks were bonded to a block of composite with a self-adhesive resin cement or with a conventional resin cement, according to the manufacturer's instructions. After 24 hours in distilled water at 37°C, the specimens were sectioned perpendicular to the bonding interface area to obtain beams with a bonding area of 0.8 mm² and submitted to a microtensile bond strength test at a crosshead speed of 0.5 mm/min. Data were statistically analyzed with one-way analysis of variance and the Games–Howell post hoc test (p = 0.05). Fractured specimens were examined under optical microscopy at 40× magnification.

Silanization resulted in higher microtensile bond strength compared to groups without silane. No significant differences were found between the conventional resin cement and the self-adhesive resin cement with silane agent (p = 0.983), and without silane agent (p = 0.877).

Silanization appears to be crucial for resin bonding to a lithium disilicate-based ceramic, regardless of the resin cement used. The self-adhesive resin cement performed as well as the conventional resin cement.

Applying one layer of a silane-coupling agent after etching the ceramic surface with hydrofluoric acid 10% enhanced the bond strength between resin cements and a glass ceramic.

Gré CP, de Ré Silveira RC, Shibata S, Lago CTR, Vieira LCC. Effect of Silanization on Microtensile Bond Strength of Different Resin Cements to a Lithium Disilicate Glass Ceramic. J Contemp Dent Pract 2016;17(2):149-153.

The aim of this study is to evaluate the effects of three different surface treatments and thermocycling on the tensile strength of a silicone lining material to denture resin.

A total of 96 cube-shaped specimens were fabricated using heat-cured polymethyl methacrylate (PMMA) denture base resin. Three millimeters of the material was cut from the midsection. The specimens were divided into four groups. The bonding surfaces of the specimens in each group received one of the following surface treatments: no surface treatment (control group), airborne particle abrasion with 110 μm alumina particles (air abrasion group), Er:yttrium aluminum garnet laser irradiation (laser group), and air abrasion + laser. After the lining materials were processed between the two PMMA blocks, each group was divided into two subgroups (n = 12), either stored in distilled water at 37°C for 24 hours or thermocycled between 5 and 55°C for 5,000 cycles. The specimens were tested in tensile and shear strength in a universal testing machine. Data were analyzed with two-way analysis of variance and Tamhane's post hoc tests (α = 0.05). The mode of failure was determined, and one specimen in each group was examined by scanning electron microscopy.

Surface-treated groups demonstrated significantly higher tensile strengths compared to the control group (p < 0.001). Nonetheless, no significant differences were found between surface-treated groups (p > 0.05). The tensile strength was significantly different between thermocycled and waterstored specimens (p = 0.021).

Altering the surface of the acrylic denture base resin with air abrasion, laser, and air abrasion + laser increased the tensile strength. Thermocycling resulted in decrease in bond strength of silicone-based liner to surface-treated acrylic resin.

Pretreatment of denture base resins before applying the soft liner materials improves the bond strength. However, thermocycling results in decrease in bond strength of soft denture liner to surface-treated acrylic resin.

Nakhaei M, Dashti H, Ahrari F, Vasigh S, Mushtaq S, Shetty RM. Effect of Different Surface Treatments and Thermocycling on Bond Strength of a Silicone-based Denture Liner to a Denture Base Resin. J Contemp Dent Pract 2016;17(2):154-159.

To evaluate the dimensional changes, reproduction of details, and surface roughness of a type IV cast and a resin used to fabricate dental models.

Two commercial brands of materials were evaluated: a type IV synthetic cast (Fuji Rock) and a polyol resin (Novox). Twenty samples were obtained from polyvinyl siloxane molds that reproduced the surface of a metal master model standardized according to the American National Standards Institute/American Dental Association specification no. 19. The materials were used according to the manufacturer's instructions and divided into two groups (n = 10). Each mold was photographed immediately after molding and 1 hour after molding. The obtained models were also photographed and measurements were obtained by using Image J software. The paired t-test was used to compare the molding materials and one-way analysis of variance (ANOVA) was used to compare the dimensional changes between the groups at a significance level of 5%.

Statistically significant differences were observed between the models fabricated with the polyol resin and type IV synthetic cast with regard to reproduction of surface details, surface roughness, and dimensional stability (p < 0.05), with the resin providing superior surface detail reproduction and greater dimensional accuracy.

The polyol resin exhibited superior behavior regarding detail reproduction, surface roughness, and dimensional change compared with the type IV synthetic cast.

Carvalhal ST, Gomes MGN, Malheiros AS, Gonçalves LM, Bandeca MC, Filho EM, De Jesus Tavarez RR. Assessment of a Synthetic Type IV Cast and a Resin Polyol Used in the Fabrication of Dental Models. J Contemp Dent Pract 2016;17(2):160-164.

The thermal expansion of the investment can be restricted by the metal casting ring because the thermal expansion of the ring is less than that of the investment. The ringless casting procedure is in use in clinical dentistry, though there is little scientific data to support its use in fixed partial dentures. In this study, marginal discrepancy of castings produced with the ringless casting technique and the conventional technique using the metal rings were compared.

A total of 30 wax patterns were fabricated directly on a metal die. Optical stereomicroscope was used to measure the marginal discrepancy between the metal die and wax patterns. A total of 15 castings were invested using Bellavest T phosphate-bonded investment with the ringless technique and 15 were invested with the same investment with a metal ring; 30 castings were produced using a nickel-chromium ceramo-metal alloy. The internal surface of the castings was not modified and seated with finger pressure. The vertical marginal discrepancy was measured using an optical stereomicroscope at a magnification of 100×. The data obtained were statistically analyzed using students t-test (paired t-test and unpaired t-test).

The castings of the ringless technique provided less vertical marginal discrepancy (240.56 ± 45.81μ) than the castings produced with the conventional metal ring technique (281.98 ± 53.05μ). The difference was statistically significant.

The ringless casting technique had produced better marginal accuracy compared with conventional casting technique. Ringless casting system can be used routinely for clinical purpose.

Kalavathi M, Sachin B, Prasanna BG, Shreeharsha TV, Praveen B, Ragher M. Marginal Accuracy of Castings Fabricated with Ringless Casting Investment System and Metal Ring Casting Investment System: A Comparative Study. J Contemp Dent Pract 2016;17(2):165-170.

Vellappallay S. Burning Mouth Syndrome: A Review of the Etiopathologic Factors and Management. J Contemp Dent Pract 2016;17(2):171-176.