title: The design and analysis of split-mouth studies: what statisticians and clinicians should know. Pit and fissure sealants in high-caries-risk individuals. In vitro assessment of laser efficiency for caries prevention in pits and fissures. Influence of erbium, chromium-doped: Yttrium scandium-gallium-garnet laser etching and traditional etching systems on depth of resin penetration in enamel: A confocal laser scanning electron microscope study Enamel pretreatment with Er:YAG laser: effects on the microleakage of fissure sealant in fluorosed teeth Split-mouth study of sealant retention with carbon dioxide laser versus acid etch conditioning. Clinical evaluation of a nanofilled fissure sealant placed with different adhesive systems: 24-month results. An in vitro investigation of pre‐treatment effects before fissure sealing Evaluation of the Effects of Enameloplasty and Air Abrasion on Sealant Micro-Leakage Pit and Fissure Sealant Retention Following Air Abrasion Preparation with Bioactive Glass and Aluminum Oxide Particles. Comparison of acid versus laser etching on the clinical performance of a fissure sealant: 24-month results. In vitro evaluation of enamel demineralization after Er:YAG and Nd:YAG laser irradiation on primary teeth. Use of Pit-and-Fissure Sealants. Microleakage of sealants after conventional, bur, and air-abrasion preparation of pits and fissures. Retention and effectiveness of dental sealant after 15 years. Evaluation of the effect of enamel preparation on retention rate of fissure sealant Sealing of pits and fissures with an adhesive resin: its use in caries prevention. Effect of acid etching and different Er:YAG laser procedures on microleakage of three different fissure sealants in primary teeth after aging. Effect of Erbium Laser on Microtensile Bond Strength of Fissure Sealant in Primary Teeth: An in vitro Study A comparative evaluation of retention of pit and fissure sealants placed with conventional acid etching and Er,Cr:YSGG laser etching: A randomised controlled trial.
abstract: The split-mouth design is a popular design in oral health research . In the most common split-mouth study , each of two treatments are r and omly assigned to either the right or left halves of the dentition . The attractiveness of the design is that it removes a lot of inter-individual variability from the estimates of the treatment effect . However , already about 20 years ago the pitfalls of the design have been reported in the oral health literature . Yet , many clinicians are not aware of the potential problems with the split-mouth design . Further , it is our experience that most statisticians are not even aware of the existence of this design . Since most of the critical remarks appeared in the oral health literature , we argue that it is necessary to introduce the split-mouth design to a statistical audience , so that both clinicians and statisticians clearly underst and the advantages , limitations , statistical considerations , and implication s of its use in clinical trials and advise them on its use in practice This paper examines the evidence demonstrating the effectiveness of sealants in high-caries-risk children and discusses the Research Triangle Institute/University of North Carolina 's ( RTI/UNC ) systematic review . The strict RTI/UNC protocol limited the number of sealant studies that could be included . This analysis exp and ed their criteria to permit additional methods of determining caries risk ( for example , past caries experience , less than two pairs of sound first permanent molars available/child in half-mouth design s ) and outcome measures in addition to DMFS ( that is , percent sealant retention , survival rates , cost-effectiveness , changes in salivary S. mutans levels ) . Nine clinical studies with a r and omized , half-mouth , clinical trial design and seven studies with observational study design s were included . There is good evidence that  sealants can be used efficaciously and effectively in high-risk  children as long as the sealant is retained . Sealants are more effective in preventing further caries and providing cost savings in a shorter time span if placed in children who have high rather than low caries risk This study aim ed to assess the in vitro efficacy of the lasers Er : YAG , Nd : YAG , and CO(2 ) operating in the low energy mode for caries prevention in pits and fissures . Forty-five caries-free enamel occlusal sections were r and omly divided into three groups : G1 - Er : YAG ( 80 mJ/2 Hz ) ; G2 - Nd : YAG Laser ( 1 W and 10 Hz ) ; and G3 - CO(2 ) Laser ( 0.4 W and 20 Hz ) . After surface treatment , the sample s were su bmi tted to challenge with acid consisting of a 10-day immersion in demineralizing ( 6 h ) and remineralizing solution ( 18 h ) . Next , enamel demineralization was quantitatively evaluated by subsurface microhardness test and polarized-light microscopy ( PLM , mm(2 ) ) and qualitatively assessed by scanning electron microscopy . The Wilcoxon test was used for comparison of each group with its own control . ANOVA ( α = 5 % ) was employed for comparison among groups , and Fisher 's LSD multiple comparison test was applied , to check the difference in means . Concerning the microhardness analyses , statistical difference between control , and experimental areas was only detected for the CO(2 ) group . Experimental values were higher than the controls . As for PLM analyses , smaller demineralized areas were measured for G2 ( Nd : YAG ) and G3 ( CO(2 ) ) compared with the control areas . In conclusion , the present findings suggest that the CO(2 ) laser should be selected in order to increase the enamel resistance to acid in pits and fissures Objective : This study was performed to assess the resin tag length penetration in enamel surface after bonding of brackets to identify which system was most efficient . Methodology : Our study was based on a more robust confocal microscopy for visualizing the resin tags in enamel . Totally , 100 extracted human first and second premolars have been selected for this study and were r and omly divided into ten groups of 10 teeth each . In Group 1 , the buccal enamel surface was etched with 37 % phosphoric acid ( 3 M ESPE ) , Group 2 with 37 % phosphoric ( Ultradent ) . In Groups 5 , 6 , and 7 , erbium , chromium-doped : Yttrium sc and ium-gallium-garnet ( Er , Cr : YSGG ) laser ( Biolase ) was used for etching the using following specifications : Group 5 ( 1.5 W/20 Hz , 15 s ) , Group 6 ( 2 W/10 Hz , 15 s ) , and Group 7 ( 2 W/20 Hz , 15 s ) . In Groups 8 , 9 , and 10 , Er , Cr : YSGG laser ( Biolase ) using same specifications and additional to this step , conventional etching on the buccal enamel surface was etched with 37 % ( 3 M ESPE ) after laser etching . In Groups 1 , 5 , 6 , 7 , 8 , 9 , and 10 3 M Unitek Transbond XT primer was mixed with Rhodamine B dye ( Sigma-Aldrich , Germany ) to etched surface and then cured for 20 s. In Group 2 , Ultradents bonding agent was mixed with Rhodamine B. In Group 3 , 3 M Unitek Transbond PLUS , Monrovia , USA , which was mixed with Rhodamine B dye ( Sigma-Aldrich , Germany ) . Group 4 , with self-etching primer ( Ultradent-Peak SE , USA ) was mixed with Rhodamine B dye ( Sigma-Aldrich , Germany ) . Later ( 3 M Unitek , Transbond XT , Monrovia USA ) [ Figure 1 ] was used to bond the modified Begg brackets ( T. P. Orthodontics ) in Groups 1 , 3 , 5 , 6 , 7 , 8 , 9 , and 10 . In Groups 2 , 4 Ultradent-Peak LC Bond was used to bond the modified brackets . After curing brackets were debonded , and enamel depth penetration was assessed using confocal laser scanning microscope . Results : Group J had a mean maximum depth of penetration of 100.876 μm , and Group D was the least having a maximum value of 44.254 μm . Conclusions : Laser alone groups had comparable depths of penetration to that of self-etching groups but much lower than conventional acid etched groups Objectives The purpose of this in vitro study was to evaluate the microleakage and penetration of fissure sealant  in permanent molar teeth with fluorosis after pretreatment of the occlusal surface . Material s and Methods A total of 120 third molars with mild dental fluorosis were r and omly divided into 6 groups ( n = 20 ) . The tooth surfaces were sealed with an unfilled resin fissure sealant ( FS ) material . The experimental groups included : 1 ) phosphoric acid etching ( AE ) + FS ( control ) ; 2 ) AE + One-Step Plus ( OS , Bisco ) + FS ; 3 ) bur + AE + FS ; 4 ) bur + AE + OS + FS ; 5 ) Er : YAG laser + AE + FS ; and 6 ) Er : YAG laser + AE + OS + FS . After thermocycling , the teeth were immersed in 0.5 % fuchsin and sectioned . Proportions of mircoleakage ( PM ) and unfilled area ( PUA ) were measured by digital microscope . Results Overall , there were significant differences among all groups in the PM ( p = 0.00 ) . Group 3 showed the greatest PM , and was significantly different from groups 2 to 6 ( p < 0.05 ) . Group 6 showed the lowest PM . Pretreatment with Er : YAG with or without adhesive led to less PM than bur pretreatment . There were no significant differences among groups in PUA . Conclusions Conventional acid etching provided a similar degree of occlusal seal in teeth with fluorosis compared to those pretreated with a bur or Er : YAG laser . Pretreatment of pits and fissures with Er : YAG in teeth with fluorosis may be an alternative method before fissure sealant application A split mouth clinical trial was undertaken to compare the  retention of fissure sealants placed using laser or acid conditioning .  After a mean follow-up period of 14.5 months , the retention rate for laser conditioning was greater than that for acid etching ( 97.9 per cent versus 94.6 per cent , respectively ) , although this difference was not statistically significant . No adverse effects occurred during or subsequent to laser conditioning procedures . It is concluded that carbon dioxide laser conditioning is a viable alternative to acid etching for fissure sealing OBJECTIVE This clinical study compared the retention rates of a nanofilled occlusal fissure sealant placed with the use of an etch- and -rinse or a self-etch adhesive over 24 months . METHODS Two-hundred and forty-four sealants were placed on the permanent premolars and molars of 16 subjects who had no restorations or sealants present on the fissures and no detectable caries . The sealants were placed with either SoloBond M two-step etch- and -rinse adhesive or FuturaBond NR one-step self-etch adhesive by four previously calibrated dentists , using a table of r and om numbers . After completion of the adhesive application , a nanofilled sealant , Gr and io Seal , was applied and light-cured . Clinical evaluations were done at baseline and at 1- , 3- , 6- , 12- , 18- and 24-month recalls . Two other calibrated examiners , who were unaware of which adhesive had been used , independently evaluated the sealants . Evaluation of the sealants on every follow-up visit involved visual examination with the aid of a dental explorer and an intra-oral mirror . Each sealant was evaluated with the following criteria : 1 = completely retained ; 2 = partial loss ; 3 = total loss . The Pearson Chi-square test was used to evaluate differences in the retention rates among the sealants used with different adhesives for each evaluation period . RESULTS For the 12-month recalls , complete retention rates of 89.3 % for the SoloBond M group and 20.5 % for the FuturaBond NR group were observed . Sixteen of the 244 restorations were unavailable after 12 months . At 24 months , a total loss of 9 sealants in the SoloBond M group and 84 in the FuturaBond NR group were observed , result ing in retention rates of 81.6 % and 15.8 % , respectively . There were statistically significant differences in retention rates between the SoloBond M and FuturaBond NR groups in all periods of evaluation ( p < 0.05 ) . No statistically significant difference between the retention rates for premolars and molars was found at each evaluation period ( p > 0.05 ) . There was no new caries formation throughout the 24-month recall period . CONCLUSION Fissure sealants placed with etch- and -rinse adhesive showed better retention rates than those placed with self-etch adhesive BACKGROUND Fissure sealants prevent occlusal caries in permanent molars .  Enamel preparation methods are used before fissure sealing . AIMS To investigate effects of bioglass air-abrasion pre-treatment with and without an adhesive , on fissure enamel of permanent teeth , with respect to etchability , microleakage and microtensile bond strength . DESIGN Half of the occlusal surfaces of 50 extracted premolars underwent bioglass air-abrasion . Dye was applied to the entire occlusal surface . Photographs were taken to score etched surface by dye uptake . Adhesive was applied to 25 of the bioglass-treated areas and all teeth were fissure sealed , sectioned , and evaluated using confocal microscopy . Buccal and lingual surfaces of a further eight premolars were acid-etched and r and omly received : air-abrasion , adhesive , both , or none before sealant application for microtensile bond strength measurement in half of the sample s immediately and half following 6 months of water immersion . RESULTS Linear mixed models and multinomial logistic regression were used ( P = 0.05 ) . Bioglass air-abrasion significantly improved enamel etchability and reduced microleakage . The addition of an adhesive made no difference to either microleakage or microtensile bond strength . The combination of bioglass abrasion and adhesive led to more cohesive , rather than adhesive , failure . CONCLUSIONS Bioglass air-abrasion improved enamel etchability and reduced microleakage irrespective of the adhesive use but neither pre-treatment affected the microtensile bond strength Objective : Micro-leakage , one of the major reasons for recurrent decays , may lead to uncontrollable flow of liquids , pulp inflammation and peri-apical pathology . The purpose of this in vitro study was to evaluate micro-leakage of pit and fissure sealants after using three different pit and fissure preparation techniques : 1 ) acid etching , 2 ) fissure enameloplasty and acid etching , and 3 ) air abrasion and acid etching . Material s and Methods : Sixty-nine extracted sound molars and premolars were r and omly divided into three groups ( 23 sample s in each group ) . Teeth were prepared using one of three occlusal surface treatments . Then the sealant was applied on the occlusal fissures of all teeth . The teeth were thermocycled and stored in normal saline . All teeth were sealed apically and coated with nail varnish and then were immersed in a 2 % solution of methylen blue . Two buccolingual sections were made . The surfaces were scored 0 to 3 for the extent of micro-leakage using a stereomicroscope . Data were analyzed by Kruskal- wallis and Dunn procedure . Results : Enameloplasty and acid etching were significantly different regarding micro-leakage ( P= 0.016 ) , but no significant difference in micro-leakage was observed between air abrasion and the other methods . Conclusion : Enameloplasty followed by acid etching produced significantly less micro-leakage than the acid etching technique . Air abrasion acid etching was better than the acid etching technique in reducing micro-leakage too PURPOSE Alumina air abrasion is an alternative for acid-etch technique for tooth preparation before placement of a fissure sealant . The aim of this study was to compare the retention of sealants placed subsequent to air abrasion with alumina and bioactive glass ( BAG ) particles . METHODS Sixty-two 6 - 12 year old children were included in this study . Using a halfmouth design , the fissures were prepared using air abrasion with alumina particles on r and omly assigned permanent m and ibular or/ and maxillary first molars on one side of the mouth ( Group 1 ) and air abrasion with BAG on the contralateral side of the mouth ( Group 2 ) . Sealants were applied on 180 teeth , and were scored as missing , partially retained , and completely retained after three , six , nine and 12 months . Data were analyzed using Friedman and Wilcoxon tests ( α=0.05 ) . RESULTS Sealant retention rates in the alumina group were higher than those in the BAG group at all time periods ( P<0.001 ) . CONCLUSIONS Sealant retention after air abrasion with alumina particles was higher than BAG over 12 months OBJECTIVE To compare the clinical performance of a pit and fissure sealant placed with the use of different enamel preparation methods , i.e. acid or Er , Cr : YSGG laser etching , over 24 months . METHODS Sixteen subjects ( 15 female , 1 male ) with no restorations or sealant present on their fissures and no detectable caries participated . Using a table of r and om numbers , a total of 112 sealants  ( 56 with acid-etching , 56 with laser etching ) were placed on the permanent premolar and molar teeth . All restorative procedures except for application of the laser were performed by the same dentist . After completion of the fissure preparation either with acid or laser , the adhesive was applied ; then a pit and fissure sealant , Clinpro Sealant , was placed and polymerized . Clinical evaluations were done at baseline and at 6- , 12- , 18- , and 24-month follow-up visits by two calibrated examiners , who were unaware of which etching method had been used . The retention of sealants and caries were evaluated with the aid of a dental explorer and an intra-oral mirror . Each sealant was evaluated using the following criteria : 1=completely retained ; 2= partial loss ; 3= total loss . The Pearson chi-square test was used to evaluate differences in the retention rates among the sealants used with different etching methods . RESULTS All patients attended the 24-month follow-up visit and all sealants were evaluated ( total recall rate 100 % ) . At the end of 24 months , 83.9 % of the sealants from laser group and 85.7 % of those from acid-etch group were recorded as " completely retained " . There were no statistically significant differences in retention rates among the preparation methods after all evaluation periods ( p>0.05 ) . No statistically significant differences were found between the retention rates of premolar and molars at each evaluation period . No secondary caries was detected in association with any sealants . CONCLUSION The clinical performance of fissure sealants placed after acid or Er , Cr : YSGG laser etching was similar OBJECTIVE This in vitro study evaluated the influence of both Er : YAG and Nd : YAG laser irradiation on  deciduous enamel demineralization .  BACKGROUND DATA Although there are still few studies on the use of the high-intensity laser for caries prevention in deciduous teeth , it is believed that its use on the dental structure can lead to a more acid-resistant surface . METHODS Forty enamel sample s obtained from 22 deciduous first molar teeth were ground and r and omly divided into four groups ( n = 10 ) : group 1 ( G1 ) , no treatment ( negative control ) ; G2 , fluoride ( positive control ) ; G3 , Er : YAG laser ( 2 Hz , 60 mJ , 40.3 J/cm(2 ) ) ; G4 , Nd : YAG laser ( 80 mJ , 10 Hz , 0.8 W ) . After the surface treatment , the sample s were su bmi tted to an acid challenge that consisted of a 5-day immersion in demineralizing ( 3 h ) and remineralizing solution ( 21 h ) . Next , a microhardness test was preformed . RESULTS Analysis of variance ( ANOVA ) and Student Newman Keuls tests were performed ( alpha = 5 % ) . The percentage of lesion inhibition for each group was as follows : G2 , 59.4 % ; G3 , 35.7 % ; and G4 , 40.4 % . As regards the percentage loss of mineral volume , there was no statistical difference between groups G2 ( 444.37 + /- 146.42 ) and G3 ( 441.81 + /- 207.08 ) when compared with group G1 ( 281.03 + /- 134.57 ) . All experimental groups presented a lower mineral loss compared with the non-irradiated sample s ( G4 ) . CONCLUSION The findings of the present study revealed that both Nd : YAG and Er : YAG lasers can be an alternative tool for enhancing deciduous enamel acid resistance BACKGROUND This article presents evidence -based clinical recommendations for the use of pit- and -fissure sealants on the occlusal surfaces of primary and permanent molars in children and adolescents . A guideline panel convened by the American Dental Association ( ADA ) Council on Scientific Affairs and the American Academy of Pediatric Dentistry conducted a systematic review and formulated recommendations to address clinical questions in relation to the efficacy , retention , and potential side effects of sealants to prevent dental caries ; their efficacy compared with fluoride varnishes ; and a head-to-head comparison of the different types of sealant material used to prevent caries on pits- and -fissures of occlusal surfaces . TYPES OF STUDIES REVIEW ED This is an up date of the ADA 2008 recommendations on the use of pit- and -fissure sealants on the occlusal surfaces of primary and permanent molars . The authors conducted a systematic search in MEDLINE , Embase , Cochrane Central Register of Controlled Trials , and other sources to identify r and omized controlled trials reporting on the effect of sealants ( available on the U.S. market ) when applied to the occlusal surfaces of primary and permanent molars . The authors used the Grading of Recommendations Assessment , Development , and Evaluation approach to assess the quality of the evidence and to move from the evidence to the decisions . RESULTS The guideline panel formulated 3 main recommendations . They concluded that sealants are effective in preventing and arresting pit- and -fissure occlusal carious lesions of primary and permanent molars in children and adolescents compared with the nonuse of sealants or use of fluoride varnishes . They also concluded that sealants could minimize the progression of non-cavitated occlusal carious lesions ( also referred to as initial lesions ) that receive a sealant . Finally , based on the available limited evidence , the panel was unable to provide specific recommendations on the relative merits of 1 type of sealant material over the others . Conclusions and practical implication s : These recommendations are design ed to inform practitioners during the clinical decision-making process in relation to the prevention of occlusal carious lesions in children and adolescents . Clinicians are encouraged to discuss the information in this guideline with patients or the parents of patients . The authors recommend that clinicians re-orient their efforts toward increasing the use of sealants on the occlusal surfaces of primary and permanent molars in children and adolescents PURPOSE The aim of this study was to compare the microleakage of unfilled and filled sealants after conventional , bur , and air-abrasion tooth preparation . METHODS Seventy-two extracted molars were r and omly divided into three groups . In group 1 , 24 teeth were prepared by pumicing and acid etching with 37 % phosphoric acid . In group 2 , 24 teeth were prepared with a 1/4-round bur in a low-speed h and piece and then acid etched . In group 3 , 24 teeth were prepared by high-speed ( 160 PSI ) microabrasion using 50 mu alpha alumina particles in a KCP 2000 machine . In each group , 12 teeth were sealed with a filled sealant and 12 teeth with an unfilled sealant . All the teeth were stored in artificial saliva for 7 days and thermocycled for 2000 cycles . Teeth were then sealed apically and coated with nail varnish 1 mm from the margins and stained in 1 % methylene blue for 24 h. Each tooth was sectioned in three locations and ranked ( 0 - 3 ) for microleakage . RESULTS There were 216 sections and 66 % showed no leakage . CONCLUSIONS Chi-square statistical analysis of the data led to the following conclusions : 1 ) superior results were obtained when the tooth surfaces were prepared by a bur , 2 ) conventionally and KCP 2000-prepared tooth surfaces yielded similar results , and 3 ) the unfilled sealant was superior to the filled sealant This l and mark study of a pit and fissure sealant found 27.6 percent complete retention and 35.4 percent partial retention on permanent first molars . In the matched pair analysis , carious or restored surfaces made up 31.3 percent of the surfaces in the sealed group and 82.8 percent in the unsealed group Background : Prevention from caries is a principle in dentistry and fissure sealant therapy is being used as a preventive method success of sealants is directly depending on their retention . Aim : The Aim of the present study is to evaluate effects of enamel preparation on sealant retention . Setting s and Design : Clinical trial . Material s and Methods : About 57 children aged 6 - 8 year old took part in this study . 200 first molar teeth of these children has been r and omly separated into two groups : A case group ( Mechanically preparation of enamel ) and a control group ( conventional method , without preparation ) . After applying fissure sealants children were followed up 6 months later . Statistical Analysis Used : Mann- U- Whitney Test was used . Results : Complete retention after 6 month follow up was 86.7 % in case group and 82.8 % in control group . No significant difference was seen between the groups after 6 month follow up . ( P = 0.508 ) . Conclusion : Although statistical evaluation did n't show significant difference , but sealant retention was more after preparation technique A clinical study to determine the effectiveness of an  enamel adhesive  in protecting pits and fissures from dental decay indicated that the technic has potential as a caries-preventive measure . The adhesive resin can be strongly bonded to enamel surfaces for comparatively long periods The purpose of this study was to evaluate the effects of different surface conditioning procedures on microleakage and unfilled area proportions of three fissure sealants(Aegis , Helioseal and Helioseal F ) in primary molar teeth . One hundred and fifty teeth were r and omly divided into five main groups according to surface conditioning procedures . Main groups were ; acid-etching(Group A ) ; laser 3.75 W(Group B ) and 5 W(Group D ) ; acid-etching combined with laser 3.75 W(Group C ) and 5 W(Group E ) . Sample s were aged by thermocycling and water bath . Afterwards , they were immersed in basic fuchsin solution for 24 h and bucco-lingual sections were obtained from each tooth . Digital images were taken using a stereo-microscope and the microleakage and unfilled area proportions were assessed by using a software system . Consequently , Aegis FS containing amorphous calcium phosphate was found to exhibit the lowest microleakage in all surface conditioning procedures . Unfilled areas were not detected in Groups C and E of all FSs Background : Laser etching has several advantages as compared with conventional acid etching . However , results of earlier studies on conditioning surfaces with erbium , chromium : yttrium – sc and ium – gallium – garnet ( Er , Cr : YSGG ) before application of the fissure sealant have been inconclusive . Aim : The study aim ed to evaluate the microtensile strength of resin-based fissure sealant bonded to primary enamel conditioned by Er , Cr : YSGG laser with varying power outputs . Material s and Methods : Fifty sound primary first molars were r and omized into the following five groups based on pretreatment choice : Group 1 : 3.5 W laser etching + acid etching ; Group 2 : 2.5 W laser etching + acid etching ; Group 3 : 3.5 W laser etching with no acid ; Group 4 : 2.5 W laser etching with no acid and Group 5 : acid etching with no laser . Acid etch was performed with 35 % orthophosphoric acid for 30 s. Laser etching was performed with Er , Cr : YSGG ( 2780 nm ) laser using G6 tips and 600 μm diameter , 2.5 W or 3.5 W power outputs , pulse duration of 140 μs and a repetition rate of 20 Hz . Sealant was applied on the buccal surface followed by an incremental buildup with composite resin . Microtensile bond strength was assessed and compared among the five groups using one- and two-way ANOVA . Results : There was no statistical difference in the mean bond strength between groups except in Group 4 ( 9.66 MPa ) ( Group 1 : 15.57 MPa ; Group 2 : 14.18 MPa ; Group 3 : 14.78 MPa ; Group 5 : 14.63 MPa ) . Conclusion : Pretreatment with 3.5 W Er , Cr : YSGG laser alone results in microtensile bond strengths similar to that produced by acid etching , indicating that enamel etching using 3.5 W Er , Cr : YSGG laser would result in the long-term success of pit and fissure sealants in primary teeth Aim : The aim of this study was to compare the retention rates of sealant placed either with conventional acid etching or Er , Cr : YSGG laser pretreatment of enamel surface . Material s and methods : This is a prospect i ve , single blind r and omised controlled clinical trial enrolling 200 permanent first molars in 50 patients , aged 6 - 12 years for sealant placement . Study followed split mouth design where each side of the arch was r and omly allocated to the two treatment group . Group A(Acid etch group ) : 37 % phosphoric acid ( Scotchbond , 3 M ESPE , Seefeld , Germany ) was applied for 15 seconds , rinsed with water for 20 seconds and then air-dried using air spray . Group L(Laser etch group ) : Fissures were prepared with an Er , Cr : YSGG laser system ( Waterlase , BIOLASE Technology , San Clemente , CA , USA ) emitting photons at a wavelength of 2.78 µm . Laser irradiation at 1.5 W ( 60 % air and 40 % water ) , in a noncontact mode , with a repetition rate of 20 Hz for 10seconds was used . Pit and fissure sealant ( 3 M ESPE , Clinpro ) was applied and cured for 20 seconds . One blinded , calibrated examiner , who was unaware of which preparation method has been used and who was not involved in the treatment procedures , evaluated the sealant at baseline and at 3 , 6 , 9 and 12 month follow-up visits . Results : It was observed that overall retention rate in group A was slightly higher as compared to group L at all time periods , however , the difference was statistically non-significant ( p-value>0.05 ) . CONCLUSION Er , Cr : YSGG laser etching is comparable to acid etching in terms of retention and patient acceptability
target: One study reported that laser preparation as an adjunct to acid-etching enhanced the retention rate .
  No significant difference in the incidence of caries was reported .
  And no significant differences were found in heart rates , oxygen saturation or degree of the patient dental anxiety between acid-etching and laser preparation .
  Conclusion The present limited evidence suggests that lasers could be an effective pretreatment method .
  The retention rate was similar to that of conventional acid etching .
background: Background This systematic review aim ed to assess the clinical effects of laser preparation compared to other types of chemical or mechanical preparation of tooth surfaces used in fissure sealant placement .