The aim of this study was to investigate retention of composite fissure sealant polymerized with standard and softstart
technique after a three year clinical trial. One hundred teeth were divided into two groups (A&B) of teeth and sealed
with composite material (Visioseal, 3M Espe) using split mouth design. Sealants were polymerized using standard
(Group A) and soft-start (Group B) techniques with commercial polymerization unit (Elipar Highlight, 3M Espe). Retention
rate in Group A was 72%. In 14 teeth sealant was partially or completely missing. Group B showed retention rate of
80%. Sealant was partially or completely missing in 10 teeth. Six new caries lesions in Group A (3) and B (3) were detected.
Mann-Whitney test did not reveal significant differences between the polymerization techniques. After three years
complete retention of sealants, regardless of the group, was 76% (76 teeth) with six new caries lesions. Soft-start polymerization
showed a comparable retention rate as the standard polymerization technique

Domagoj Glavina

Dubravka Negovetić Vranić

Ilija Škrinjarić

Martina Majstorović

Sandra Anić Milošević

Većeslav Bergman

English

Hrčak - Portal of scientific journals of Croatia

Coll. Antropol. 31 (2007) 4: 1089–1092Original scientific paperSoft-Start Polymerization of Fissure Sealant:Retention after Three YearsDomagoj Glavina1, Dubravka Negoveti} Vrani}1, Sandra Ani} Milo{evi}2, Ve}eslav Bergman3,Martina Majstorovi}1 and Ilija [krinjari}11 Department of Pedodontics, School of Dental Medicine, University of Zagreb, Zagreb, Croatia2 Department of Orthodontics, School of Dental Medicine, University of Zagreb, Zagreb, Croatia3 Croatian Health Insurance Agency, Zagreb, CroatiaA B S T R A C TThe aim of this study was to investigate retention of composite fissure sealant polymerized with standard and soft-start technique after a three year clinical trial. One hundred teeth were divided into two groups (A&B) of teeth and sealedwith composite material (Visioseal, 3M Espe) using split mouth design. Sealants were polymerized using standard(Group A) and soft-start (Group B) techniques with commercial polymerization unit (Elipar Highlight, 3M Espe). Reten-tion rate in Group A was 72%. In 14 teeth sealant was partially or completely missing. Group B showed retention rate of80%. Sealant was partially or completely missing in 10 teeth. Six new caries lesions in Group A (3) and B (3) were de-tected. Mann-Whitney test did not reveal significant differences between the polymerization techniques. After three yearscomplete retention of sealants, regardless of the group, was 76% (76 teeth) with six new caries lesions. Soft-start polymer-ization showed a comparable retention rate as the standard polymerization technique.Key words: fissure sealants, soft-start polymerization, sealant retention rateIntroductionIn order to achieve maximum caries preventive effectthere must be perfect adhesion of the sealant material totooth enamel. Perfect adhesion of the material should bemaintained not only while setting but also during func-tion (including challenge of thermal and mechanical cy-cling). Complete retention of sealant material in the fis-sures ensures good adhesion to enamel. Studies con-ducted by Feigal (1998), Llodra et al. (1993), Heidman etal. (1990) and Wendt et al. showed good caries preventioneffect if retention of sealant in the occlusal surfaces isachieved1–4.Polymerization shrinkage and consequently develop-ment of shrinkage stress is the main problem associatedwith the curing of composite dental materials. As a resultof this phenomenon debonding of the curing materialfrom the dental tissues occurs, enabling the occurrenceof marginal gaps5–8. Because of the morphology of occlu-sal surfaces calculation of the configuration factor value(so called C factor) for occlusal surfaces is very difficult.However, even very imprecise calculation of bonded andunbonded occlusal surfaces gives a result of more than 5,which means development of maximum shrinkage stress9.The main clinical problems associated with gap forma-tion are microleakage of fluids, bacteria and debris, cre-ating secondary caries lesions and possible pulpal pathol-ogy.There are several methods proposed in the literatureto compensate polymerization shrinkage stress and mini-mise the deteriorating effect of marginal gaps. One of theproposed methods is by varying the time and intensity ofillumination during polymerization of the composite ma-terial, so-called SOFT-START polymerization10,11.The general idea of Soft-start polymerization tech-nique is to enable prolonged flow of curing material (inthe pre-gel phase) by using low intensity light during thefirst 10 s of polymerization, allowing the molecules in thematerial to rearrange and create quality adhesion to den-tal tissue. Several combinations of light intensity and il-lumination times have been proposed in order to achieve1089Received for publication October 15, 2007the best material properties and to minimise material di-mensional changes12–14.The aim of this study was to analyse the retentionrate of dental sealants polymerized with standard andsoft-start polymerization techniques after 3 years of clin-ical service.Materials and MethodsThe study was performed on 100 teeth (65 patients,7–12 years old); first and second molars, with well delin-eated fissure morphology, divided into two groups of 50using split mouth design. The procedures, possible dis-comfort or risk, as well as possible benefits were ex-plained fully to the parents, and their informed consentwas obtained prior to the investigation. The study wasapproved by the Ethics Committee of the University ofZagreb, School of Dental medicine.Teeth were sealed with composite sealant materialVisioseal (3M ESPE). Isolation of teeth prior to the seal-ant placement was secured using cotton rolls. One oftooth in the pair was polymerized with standard and an-other with soft start method. Teeth on the left side of themouth were polymerized using soft start while teeth onthe right side were polymerized with standard method.The method of application of the sealant material wascarried out in accordance with the manufacturer’s rec-ommendations, which included enamel etching with pho-sphoric acid for 20 s, 20 s rinsing with water and 20 s dry-ing of the occlusal surface. Polymerization of sealantswas performed by the commercially available unit EliparHighlight (3M ESPE) with integrated different modes ofpolymerization. Protocol for soft start method was set bythe manufacturer in the following way: 10 s illuminationwith intensity of 200 mW/cm2 following 30 s with inten-sity of 800 mW/cm2. Standard polymerization was 40 swith light intensity of 800 mW/cm2.Evaluation of sealantretention was performed using the method proposed byKilpatrick et al.15 as follows: 1 – intact sealant; 2 – 1/3 ofsealant missing; 3 – 2/3 of sealant missing; 4 – whole seal-ant missing. Presence of new caries lesions was evalu-ated in two categories: 1 – absent, 2 – present. The ob-tained data were analysed using non-parametric Mann-Whitney U test. Mann-Whitney U test is a non-paramet-ric alternative to t-test for independent samples and usescoding variable (independent variable) for analysis. It isalso suitable for small samples and for samples largerthan 20 sampling distribution approaches to normal dis-tribution.ResultsAfter three years of clinical service complete retentionof sealants polymerized with soft-start method was ob-served in 40 teeth (80%) while sealants were partiallymissing in 5 teeth (10%) and completely missing in 5teeth (10%). In the group polymerized with standardmethod complete retention was noted in 36 teeth (72%)and the sealants were partially and completely missingin 14 teeth (28%). Mann-Whitney test did not reveal sig-nificant difference in retention between the polymeriza-tion methods (Table 1). Incidence of new caries lesionsafter three years in the group of teeth polymerized withsoft start method was 3 (6%) as well as in the group poly-merized with standard method. Also, with regard to car-ies incidence Mann-Whitney test did not reveal signifi-cant statistical difference between the polymerizationmethods (Table 2). Distribution of sealed teeth in the up-per and lower jaws were as follows: 48 pairs in themaxilla with complete retention rate of 72.9%, and 52pairs in the mandible with complete retention of 78.8%(Table 3). There was no significant difference betweenthe upper and lower jaw regarding retention. New carieslesions incidence was the same in the maxilla and mandi-ble, 3 (6.2%) with no significant statistical difference (Ta-ble 4). Generally, complete retention of Visioseal sealantD. Glavina et al.: Soft Start Polymerization of Fissure Sealant, Coll. Antropol. 31 (2007) 4: 1089–10921090TABLE 1SEALANT RETENTION RATE AFTER THREE YEARSTechnique ofpolymerizationSealant retention after 3 years Mann-Whitney(p)1 2 3 4 TotalStandard%367210202424501000.46 (ns)Soft-start%40805100051050100Total 76 15 2 7 100p>0.05, ns – not significantTABLE 2INCIDENCE OF NEW CARIES LESIONS AFTER THREE YEARSTechniqueof polymer-izationIncidence of new caries lesionsafter 3 years Mann-Whitney (p)1 2 TotalStandard%479436501001.0 (ns)Soft-start%47943650100Total 94 6 100p>0.05, ns – not significantmaterial after three years of clinical service was 76%, re-gardless of the polymerization technique.DiscussionReduced caries incidence noted in previous studiesshowed that retention rate is directly connected with thepreventive effect4,16–18. Obtained results in the presentstudy regarding retention rate were in accordance withother studies. Rock et al.16 showed for FluroShield 70%retention after three years, with significantly better per-formance on lower molars. The same author19 noted 77%retention after three years for light cured sealants thatwas better compared to chemically cured sealants. Raa-dal et al.20 obtained very high values of retention afterthree years of 97%, and Eidelman et al.21 also reportedhigh values of 91%, proving that 20s etching time is justas efficient as 60s. A study performed by Lygidakis etal.22 showed retention rate after four years between81–93% with no significant statistical difference betweencotton roll isolation and rubber dam method. They alsonoted better retention of sealant in lower molars than inupper molars with the explanation that material flowingdistally in the upper molar leaves only a thin layer of ma-terial susceptible to fracture. In the present study thesame result was obtained although not statistically sig-nificant. One of the reasons could be visibility problemsin the upper distal (first or second molars) teeth com-bined with technical sensitivity of the procedure. Al-though not significant the retention rate of sealants poly-merized with soft start method was better than the re-tention rate after standard polymerization. There areseveral elements that must be taken into consideration.According to studies by Labella et al.23 and Price et al.24,polymerization shrinkage of unfilled resin can amount to11% which is 3–4 times more compared to composite ma-terials. Prolonged flow for compensation of polymeriza-tion shrinkage can be of great importance for the sealantmaterial. Thickness of the sealant material applied in thefissures also can influence polymerization shrinkage. Intheir study Alster et al.5 showed increased values of con-traction stress for very thin (50–200 mm) composite sam-ples. Thickness of the sealant material applied on an un-even occlusal surface is not uniform in all parts of thepits and fissures, leading to different polymerization con-traction stress. Additionally, configuration factor (C fac-tor) defined as the relation of bonded and unbondedsurfaces25 is very difficult to calculate and even imprecisecalculation provides value of more than 5, which meansdevelopment of maximal shrinkage stress. The resultsobtained in retention rate using soft start polymerizationmethod corroborate results obtained in studies on filledcomposite materials26–30. Prolonged pre-gel phase and re-arrangement of polymer chains in sealant material dur-ing setting creates better adaptation of sealant materialto tooth enamel. Also, shrinkage directed to bonded sur-faces, as shown by Versluis et al.31, can influence reten-tion and formation of marginal gaps. However, oneshould be very cautious in interpretation of the results,because of other factors that can influence retentionsuch as occlusion, diet (food consistency), hygiene etc. Astudy by Fleming et al.32 showed no significant statisticaldifference in cuspal movement of premolar teeth or mi-croleakage after polymerization of composite restorationmaterial with soft-start technique compared to standardpolymerization. Emerging on the market are new poly-merization devices such as LED polymerization unitsand plasma units, as well as very high intensity halogenlight units, which may improve the retention rate of den-tal sealants. According to Visvanathan et al.33 soft startmode is not as efficient in LED polymerization units al-though they enable prolonged gel phase of the materialduring polymerization. Also the technique of applyingsealants can influence the retention rate, and this willprobably be the objective of further investigations.D. Glavina et al.: Soft Start Polymerization of Fissure Sealant, Coll. Antropol. 31 (2007) 4: 1089–10921091TABLE 4INCIDENCE OF NEW CARIES LESIONS IN THE UPPER ANDLOWER JAWLocationof sealantIncidence of new caries lesionsafter 3 years Mann-Whit-ney (p)1 2 TotalMaxilla%4593.836.2481000.91 (ns)Mandible%4994.235.852100Total 94 6 100p>0.05, ns – not significantTABLE 3RETENTION OF SEALANTS IN THE UPPER AND LOWER JAWLocation ofsealantSealant retention after 3 years Mann-Whitney(p)1 2 3 4 TotalMaxilla%3572.9816.712.148.3481000.48 (ns)Mandible%4178.8713.511.935.852100Total 76 15 2 7 100p>0.05, ns – not significantConclusionOn the basis of the obtained results it is possible todraw the following conclusions:1. Retention rate of sealants polymerized with soft startpolymerization method was very similar to the stan-dard polymerization technique and no statistically sig-nificant differences were observed.2. Both polymerization techniques can be considered ofequal value and can be used in clinical practice.R E F E R E N C E S1. FEIGAL RJ, Pediatr Dent, 20 (1998) 85. — 2. LLODRA JC, BRAVOM, DELGADO-RODRIQUES M, BACA P, GALVEZ R, Community DentOral Epidemiol, 2 (1993) 261. — 3. HEIDMANN J, POULSEN S, MATHI-ASSEN F, Community Dent Oral Epidemiol, 7 (1990) 379. — 4. WENDTLK, KOCH G, BIRKHED D, Community Dent Oral Epidemiol, 29 (2001)302. — 5. ALSTER D, FEILZER AJ, DE GEE AJ, DAVIDSON CL, DentMater, 13 (1997) 146. — 6. KINOMOTO Y, TORII M, J Dent, 26 (1998)165. — 7. SAKAGUCHI RL, VERSLUIS A, DOUGLAS WH, Dent Mater,13 (1997) 233. — 8. CIUCCI B, BOUILLAGUET S, DELALOYE M,HOLZ J, J Dent, 25 (1997) 305. — 9. FEILZER AJ, DE GEE AJ, DAVID-SON CL, J Dent Res, 66 (1987) 1636. — 10. DAVIDSON CL, FEILZERAJ, J Dent, 25 (1997) 435. — 11. LOVELL LG, NEWMAN SM, DONALD-SON MM, BOWMAN CN, Dent Mater, 19 (2003) 458. — 12. UNTER-BRINK GL, MUESSNER R, J Dent, 23 (1995) 183. — 13. MEHL A, HI-CKEL R, KUNZELMANN K-H, J Dent, 25 (1997) 321. — 14. YAP AUJ,NG SC, SIOW KS, Oper Dent, 26 (2001) 260. — 15. KILPATRICK NM,MURRAY JJ, MCCABE JF, J Dent, 24 (1996) 399. — 16. ROCK WP,FOULKES EE, PERRY H, SMITH AJ, J Dent, 24 (1996) 275. — 17.DENNISON JB, STRAFFON LH, SMITH RC, J Am Dent Assoc, 131(2000) 597. — 18. RAJI] Z, GVOZDANOVI] Z, RAJI]-ME[TROVI] S,BAGI] I, Coll Antropol, 24 (2000) 151. — 19. ROCK WP, WEATHERILLS, ANDERSON RJ, Br Dent J, 168 (1990) 323. — 20. RAADAL M, UTKI-LEN AB, NILSEN OL, Int J Paediatr Dent, 6 (1996) 235. — 21. EIDEL-MAN E, SHAPIRA J, HOUPT M, J Dent Child, 55 (1988) 119. — 22. LY-GIDAKIS NA, OULIS KI, CHRISTODOULIDIS A, J Clin Pediatr Dent,19 (1994) 23. — 23. LABELLA R, LAMBRECHTS P, VANMEERBEEK B,VANHERLE G, Dent Mater, 15 (1999) 128. — 24. PRICE RB, RIZKALLAAS, HALL GC, Am J Dent, 13 (2000) 176. — 25. FEILZER AJ, DE GEEAJ, DAVIDSON CL, J Dent Res, 66 (1987) 1636. — 26. YAP AUJ, SOHMS, SIOW KS, Oper Dent, 27 (2002) 44. — 27. HOFMANN N, SIE-BRECHT C, HUGO B, KLAIBER B, Oper Dent, 28 (2003) 160. — 28.BRACKETT WW, COVEY DA, ST GERMAIN HA JR, Oper Dent, 27(2002) 218. — 29. CAVALCANTE LMA, PERIS AR, AMARAL CM, AM-BROSANO GMB, PIMENTA LAF, Oper Dent, 28 (2003) 200. — 30.CUNHA LG, SINHORETI MAC, CONSANI S, SOBRINHO LC, OperDent, 28 (2003) 155. — 31. VERSLUIS A, TANTBIROJN D, DOUGLASWH, J Dent Res, 77 (1998) 1435. — 32. FLEMING GJ, CARA RR, PALINWN, BURKE FJ, Dent Mater, 23 (2007) 637. — 33. VISVANATHAN A,ILIE N, HICKEL R, KUNZELMANN KH, Dent Mater 23 (2007) 777.D. GlavinaDepartment of Pedodontics, School of Dental Medicine, University of Zagreb, Gunduli}eva 5, 10000 Zagreb, Croatiae-mail: domagoj.glavina@zg.t-com.hrPE^A]ENJE FISURA PRIMJENOM SOFT-START POLIMERIZACIJE:RETENCIJA NAKON 3 GODINES A @ E T A KSvrha ovog istra`ivanja bila je evaluacija stupnja retencije kompozitne pe~atne smole polimerizirane standardnom isoft-start tehnikom polimerizacije nakon tri godine klini~ke primjene. Stotinu zuba podijeljenih u dvije skupine (A&B)pe~a}eno je kompozitnom pe~atnom smolom (Visioseal, 3M Espe). Pe~atna smola polimerizirana je primjenom stan-dardne (skupina A) i soft-start (skupina B) tehnike upotrebom polimerizacijske lampe (Elipar Highlight, 3M Espe).Stupanj retencije pe~ata u skupini A bio je 72%. U 14 zuba pe~at je djelomi~no ili potpuno nedostajao. U skupini Bstupanj retencije bio je 80%. Materijal za pe~a}enje je djelomi~no ili potpuno nedostajao u 10 zuba. Ustanovljeno je {estnovih karijesnih lezija, tri u skupini A i tri u skupini B. Za statisti~ku analizu kori{ten je Mann-Whitney test. Nijeustanovljena statisti~ki zna~ajna razlika u stupnju retencije izme|u tehnika polimerizacije. Potpuna retencija mate-rijala za pe~a}enje u obje skupine nakon tri godine bila je 76% (u 76 zuba) uz {est novih karijesnih lezija. Ustanovljen jeusporediv stupanj retencije izme|u standardne i soft-start tehnike polimerizacije.D. Glavina et al.: Soft Start Polymerization of Fissure Sealant, Coll. Antropol. 31 (2007) 4: 1089–10921092

Soft-Start Polymerization of Fissure Sealant: Retention after Three Years

Abstract

Similar works

Full text

Available Versions

Hrčak - Portal of scientific journals of Croatia