International Journal of Paediatric Dentistry 2004; 14: 272–278 272 © 2004 BSPD and IAPD Blackwell Publishing, Ltd. Microleakage assessment of pit and fissure sealant with and without the use of pumice prophylaxis G. ANSARI 1 , K. OLOOMI 2 & B. ESLAMI 3 1 Department of Pediatric Dentistry, 2 General Dental Practitioner, and 3 Department of Oral and Maxillofacial Pathology, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran Summary. Objectives. This study evaluated the effect of pumice prophylaxis on the level of microleakage around and between the sealant and enamel. Materials and methods. A total of 32 freshly extracted sound upper first premolars, assigned as suitable for sealant application, were chosen and divided randomly into two groups: (1) a test group, without prophylaxis; and (2) a control group, with prophylaxis. Sealant was applied to all teeth using the same conventional technique, with prophylaxis being omitted in the test group. The sealed teeth were thermocycled (120 × 30 s, 5 and 55 °C cycles) and then immersed in 2% Basic Fuchsin solution for 72 h. Each tooth was sec- tioned and examined for dye penetration under a stereomicroscope (× 60 magnification). Results. No dye penetration was seen in 19 (29·6%) of the teeth in the test group and 36 (56·2%) of the teeth in the control group. Dye had penetrated to the base of the fissure in 31 (48·4%) of the teeth in the test group and 23 (35·9%) of the teeth in the control group. Using a chi-square test for trend, the frequency of microleakage was significantly higher in the test group compared to the controls (P < 0·016). Conclusion. Prophylaxis has a role in improving sealant retention. Removing this step may cause an increase in microleakage. Introduction The success of pit and fissure sealant in preventing caries in fissures has been well-documented [1–3]. Indeed, it is considered to be the most effective caries- preventive measure that may be offered to a patient [4]. To achieve the greatest benefit, sealants should bond appropriately to the enamel surface [1–3]. It has been agreed that adequate retention of a sealant will be achieved if the tooth has a wide surface area, and deep, irregular pits and fissures. A number of studies have suggested that bur preparation and air abrasion will enhance sealant penetration and adapta- tion, by virtue of providing a greater surface area for retention as well as an increase in the bulk of sealant which improves wear resistance [5–8]. It has also been suggested that a combination of these measures could lead to increased clinical longevity. Conversely, a few investigators have reported no significant difference between conventional acid etch alone, and bur preparation followed by acid etch- ing of pit and fissures [9,10]. A significantly greater level of microleakage was seen following the use of air abrasion alone compared to that following either acid etching alone or tooth preparation using a bur together with acid etching [11–14]. Hatibovic- Kofman et al. (2001) indicated that microleakage may be prevented most effectively with a combina- tion of mechanical air abrasion and chemical acid etching [10]. The surface should be clean and dry at the time of the material placement [1–3]. This means that sealant should be applied after cleaning and polishing the teeth [1]. The use of drying agents such as ethyl Correspondence: Ghassem Ansari, Department of Pediatric Dentistry, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Evin, Iran. E-mail: koloomi@yahoo.com