Bioactivity and biocompatibility of two fluoride containing bioactive glasses for dental applications.

OBJECTIVE: Bioactive glasses (BAG) form, in contrast to formerly used implant materials, a stable bond with tissues, especially bone, when implanted. Nowadays BAGs are often mixed with a cement/composite that hardens in situ to broaden its applications in dentistry or orthopedics. The bioactivity and biocompatibility of possible BAG candidates for BAG-cement/composite development were evaluated. METHODS: Two fluoride containing BAGs were tested: a Na+-containing (45S5F), based on the first commercial BAG, and a Na+-free BAG (CF9), with a higher Ca2+ and PO43- content. BAGs were tested on their bioactivity upon immersion in SBF for 7days by evaluating the surface changes by FT-IR, SEM, EDS and PO43- and Ca2+ uptake and/or release from SBF. Moreover, the biocompatibility of the BAGs was investigated with a direct contact cell viability study with HFF cells and a cell adhesion study with MG-63 cells. RESULTS: The Na+-free BAG, CF9, showed the highest potential to bioactivate cements because of its high Ca2+-release and apatite (Ap) formation, as evidenced by SEM pictures and corresponding EDX patterns. FT-IR confirmed the formation of an Ap layer. Moreover CF9 had a higher biocompatibility than 45S5F. SIGNIFICANCE: For the bioactivation of GICs/composites in order to enhance bonding and remineralization of surrounding tissues, fluoride containing BAG may have advantages over other BAGs as a more stable fluorapatite can be formed. CF9 may be an excellent candidate therefore.

Effects of root surface debridement using Er:YAG laser versus ultrasonic scaling - a SEM study.

OBJECTIVE: Despite promising results of Er:YAG laser in periodontal debridement, to date there is no consensus about the ideal settings for clinical use. This experimental clinical trial aimed to determine the effects of debridement using Er:YAG laser and to compare with ultrasonic treatment. MATERIALS AND METHODS: Sixty-four teeth were divided into two in vivo and in vitro subgroups. Each tooth received ultrasonic treatment on one side and Er:YAG laser debridement at either 60, 100, 160 or 250 mJ pulse(-1) and at 10 Hz on the other side on a random basis. All samples were morphologically analyzed afterwards under scanning electron microscope for surface changes and dentinal tubules exposure. Treatment duration (d) was also recorded. RESULTS: Laser debridement produced an irregular, rough and flaky surface free of carbonization or meltdown while ultrasound produced a relatively smoother surface. The number of exposed dentinal tubules (n) followed an energy-dependent trend. The number of exposed tubules among the in vivo laser groups was n 60 mJ = n 100 mJ < n 160 mJ < n 250 mJ (P < 0.001). Also 160 and 250 mJ lasers led to significantly more dentinal exposure than ultrasound under in vivo condition. Within the in vitro laser groups, dentinal tubules exposure was n 60 mJ < n 100 mJ < n 160 mJ < n 250 mJ (P ≤ 0.0015). Furthermore, in vitro laser treatments at 100, 160 and 250 mJ led to significantly more dentinal denudation than ultrasound. Treatment duration (d) for the in vivo groups was d 60 mJ > d 100 mJ > d Ultrasound = d 160 mJ > d 250 mJ (P ≤ 0.046), while for the in vitro groups it was d 60 mJ > d 100 mJ = d Ultrasound = d 160 mJ >d 250 mJ (P ≤ 0.046). CONCLUSIONS: Due to excessive treatment duration and surface damage, Er:YAG laser debridement at 60 and 250 mJ pulse(-1), respectively, is not appropriate for clinical use. Although laser debridement at 100 and 160 mJ pulse(-1) seems more suitable for clinical application, compared to ultrasound the former is more time-consuming and the latter is more aggressive. Using a feedback device or lower pulse energies are recommended when using laser in closed field.