Tiêu đề 9- light curing systems .. ksr .. 2025 (1).pdf ✅

light curing pre-cl. op. I 2 2025 Kasr Dr_M.Bedawi b- intensity of light - the intensity of the curing unit should not be less than 400 mw/cm2 .  the new generations of light curing devices have intensity above 1000 mw/cm2. - it can be quantified by a radiometer. aim of light curing 1. achieving high monomer conversion to full depth of the resin composite material. 2. shorten the possible exposure time. 3. low shrinkage stress. factors affecting the light curing - factors affecting the degree of polymerization (depth of cure Or degree of conversion) of composite : 1- tooth & cavity-related factors a- depth of the cavity preparation : - in deeper areas, the distance between the light tip & composite increases, causing attenuation of light intensity & less depth of cure. - when cavity is deep (↑ 5 mm), three-side curing should be done. b- intervening tooth structure : - curing through tooth structure, decreases the depth of cure. - in such case, intensity &/Or time of curing should be increased. 2- composite-related factors a- thickness of composite increment : - increasing the thickness, decreases the depth of cure. - composite should be placed in increments of not more than 1.5-2 mm to ensure proper polymerization. b- shade of composite : - darker composite shades, cure more slowly & less deeply than lighter shades. - dentin shade need more curing than body shade ↑ enamel shade ↑ translucent shade. d- type of photo initiator : camphoroquinone Lucerin & PPD - opaque. - used in yellowish shades “dentin shades”. - blue light (long wavelength 450-495 nm). - translucent. - used in enamel & bleaching shades. - violet light (short wavelength 380-450 nm).