Introduction: Repair of old composite restorations is a conservative approach. This study sought to compare the effects of two adhesive systems on the bond strength of repaired composites prepared by three different surface treatments: erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation, air-abrasion, and bur preparation.Methods: Eight microhybrid (Polofil Supra, VOCO, Germany) composite resin blocks were fabricated. The blocks were aged and assigned to four groups as stated by the surface treatment: (I) air-abrasion (50 μ aluminum oxide particles), (II) diamond bur (fine grit), (III) Er:YAG laser (3 W output power, 300 mJ energy) and (IV) control. After surface treatment, the blocks were acid-etched and salinized. Each group was divided two subgroups, and the Clearfil SE Bond or All-Bond Universal was applied on their surface. Composite resin was bonded to the aged composites. The blocks were cut into eight samples, and the microtensile bond strength (MTBS) was measured.Results: The maximum MTBS was noted in the air-abrasion (25.1 + 6 MPa) group, followed by the Er:YAG laser (21.2 + 4.7 MPa). The mean MTBS in laser and air-abrasion groups was significantly higher than that in other groups (P 0.05). Composite resin conditioning by All-Bond Universal in laser and air-abrasion groups yielded significantly higher MTBS than the Clearfil SE Bond (P < 0.05).Conclusion: All surface treatments created acceptable bond strength. The surface treatment of the aged composite by the Er:YAG laser or air-abrasion along with the application of silane and All-Bond Universal provide high bond strength.

Introduction: Focal epithelial hyperplasia (FEH), also known as Heck’s disease, is a humanpapilloma virus induced proliferation of epithelial cells, which causes asymptomatic lesions in theoral mucosa. Heck’s disease is more prevalent among children or in a family. Despite the selflimitation of lesions, they may progress or cause esthetical and functional discomforts. Hence, earlydiagnosis is necessary.Case Presentation: A middle-aged man with a peripheral multiple soft, elevated, sessile, smooth,lobulated surface and nodular lesions in his right buccal mucosa was referred. The dimensions of thelesions varied from 5 to 25 mm. Through clinical and histopathological examinations, Heck’s diseasewas diagnosed. The diode laser (wavelengths of 980 nm), 1-W power using continuous waves) wasapplied serially (in 2 sessions with a 1-week interval) for surgically removing the lesions. The patientwas followed up for 6 months with no lesion recurrence, and gradual healing was observed.Conclusion: The laser is an effective treatment with no scar remaining after the procedure and bringssatisfaction to patients.

Objectives: This study sought to assess the efficacy of antimicrobial photodynamic therapy (aPDT) with phycocyanin and diode laser for reduction of Porphyromonas gingivalis (P. gingivalis). Materials and Methods: In this in vitro, experimental study, first the minimum inhibitory concentration (MIC) of phycocyanin, the sub-lethal exposure time of diode laser, and the sub-lethal dose of aPDT were determined. The wells containing P. gingivalis suspension were randomly divided into three experimental groups for exposure to ½ MIC phycocyanin for 5 min, minimum lethal dose of diode laser (635 nm, 4 min), and aPDT with phycocyanin and diode laser. The positive control group was exposed to 0.2% chlorhexidine (CHX) for 5 min, and the negative control group received no treatment. The colony count was calculated in the five groups and compared using one-way ANOVA and t-test. Results: aPDT with diode laser (635 nm, 4 min) and 125 µg/mL phycocyanin caused significantly greater reduction of P. gingivalis count (mean reduction of 44.24%) compared with other groups (P<0.0001). Minimum and maximum colony counts were noted in 0.2% CHX and negative control groups, respectively. The reduction in colony count was significant in all experimental groups, compared with the control group (P<0.0001). Conclusion: aPDT with 635 nm diode laser and phycocyanin can significantly decrease P. gingivalis count in vitro. Considering the conservative nature of this modality, it may be used for decontamination of peri-implant.