Evaluation of the genotoxic effects of fixed appliances on oral mucosal cells and the relationship to nickel and chromium concentrations: an in-vivo study. Enamel cracks and ceramic bracket failure during debonding in vitro. Enamel matrix proteins in the treatment of intra-bony defects. A prospective 24-month clinical trial. In vivo remineralising effect of GC tooth mousse on early dental enamel lesions: SEM analysis. Microsurgical access flap and enamel matrix derivative for the treatment of periodontal intrabony defects: a controlled clinical study. Enamel matrix proteins and guided tissue regeneration with titanium-reinforced expanded polytetrafluoroethylene membranes in the treatment of infrabony defects: a comparative controlled clinical trial. Clinical and radiographic effects of enamel matrix derivative in the treatment of intrabony periodontal defects: a 12-month longitudinal placebo-controlled clinical trial in adult periodontitis patients. Enamel matrix proteins and bovine porous bone mineral in the treatment of intrabony defects: a comparative controlled clinical trial. Evaluation and comparison of the microhardness of enamel after bleaching with fluoride free and fluoride containing carbamide peroxide bleaching agents and post bleaching anticay application: An in vitro study The Effects of Composite Resin Types and Debonding Pliers on the Amount of Adhesive Remnants and Enamel Damages: A Stereomicroscopic Evaluation Clinical performance of novel resin composites in posterior teeth: 18-month results. A comparison between enamel matrix proteins used alone or in combination with bovine porous bone mineral in the treatment of intrabony periodontal defects in humans. Orthodontic bracket removal using conventional and ultrasonic debonding techniques, enamel loss, and time requirements. Evaluation of efficacy of enamel matrix derivative in the treatment of intrabony defects: a 24-month multicenter study. Evaluation of the Effects of Enameloplasty and Air Abrasion on Sealant Micro-Leakage Microleakage of composite restorations after acid or Er-YAG laser cavity treatments. Histologic evaluation of human intrabony defects following non-surgical periodontal therapy with and without application of an enamel matrix protein derivative.
INTRODUCTION The release of metal ions from fixed orthodontic appliances is a source of concern . The aim of this study was to evaluate genotoxic damage in the oral mucosal cells of patients wearing fixed appliance , and the nickel and chromium ion contents in these cells . METHODS Twenty patients undergoing orthodontic treatment formed the experimental group , and 20 untreated subjects comprised the control group . Oral mucosal smears were collected at 2 times : at debonding and 30 days after debonding . The smears were stained with Papanicolaou stain and studied under a light microscope to evaluate the presence of micronuclei .  Inductively coupled plasma-mass spectrometry was used to quantify the presence of metal ions . The data were subjected to the Mann-Whitney U test and the Spearman rank correlation test . RESULTS The mean micronuclei frequency was significantly higher in the treated group than in the control group at debonding ; the difference was smaller and not statistically significant 30 days after debonding . The nickel and chromium ion contents in the experimental group were not significantly higher than in the control group . No correlation could be established between micronuclei frequency and metal ion content . CONCLUSIONS Nickel and chromium alloys of orthodontic appliances emit metal ions in sufficient quantities to induce localized genotoxic effects , but these changes revert on removal of the appliances OBJECTIVE To test the null hypothesis that no difference in bracket failure characteristics is noted when use of a new ceramic bracket debonding instrument is compared with the use of conventional pliers . MATERIAL S AND METHODS Thirty maxillary premolars were r and omly assigned to one of two groups . In group 1 , Clarity collapsible ceramic brackets ( 3 M Unitek , Monrovia , Calif ) were debonded with the use of conventional Utility/Weingart ( 3 M Unitek , Monrovia , Calif ) pliers . In group 2 , Clarity brackets were debonded with a new Debonding Instrument ( 3 M Unitek ) . For all teeth , the same bracket bonding system was used . Following debonding , teeth and brackets were examined under 10x magnification for assessment of bracket failure ( fracture ) and of residual adhesive on the enamel surface . Enamel surfaces were visualized with transillumination prior to bonding and after removal of the residual adhesive , so the effect of the debonding forces could be determined . RESULTS The results of Adhesive Remnant Index comparisons indicated that a statistically significant difference ( chi2 = 8.73 ; P = .013 ) in bond failure patterns was apparent when the two groups were compared . Brackets debonded with the new instrument showed a greater tendency for the adhesive to be removed from the tooth during debonding . CONCLUSIONS The hypothesis is rejected . Although the incidence of enamel damage following debonding was similar in the two groups , the use of the new Debonding Instrument decreased the incidence of bracket fracture BACKGROUND A growing flow of recent evidence indicates enamel matrix derivative ( EMD , Emdogain ) as a useful tool for the regeneration of periodontal tissues . This prospect i ve clinical study aim ed to evaluate the efficacy of EMD combined with surgical treatment of periodontal intra-bony defects , as compared with surgery alone , up to 24 months of follow-up . METHODS Twenty-four intra-bony defects were treated in 24 patients in a single clinical centre . Each defect had intra-bony depth ( IBD ) > or = 4 mm and probing pocket depth ( PPD ) > or = 6 mm . Patients were r and omly assigned to either test or control group . Plaque index ( PI ) , gingival index ( GI ) , PPD and periodontal attachment level ( PAL ) were assessed at baseline pre-surgical examination at the site to be treated . Full mouth plaque score ( FMPS ) and full mouth bleeding score ( FMBS ) were also evaluated . Twelve patients were treated by simplified papilla preservation flap technique ( control group ) , while 12 patients were treated with the same surgical technique plus EMD after ethylenediamine tetraacetic acid root conditioning ( test group ) . Any probing at the involved sites was avoided in the first year post-surgery . Radiographs were taken at baseline , 12 and 24 months after surgery using customized bite blocks . Intra-bony defect depth ( IBD ) and angle ( IBA ) were measured from X-rays by a computer-aided technique . At 12 and 24 months post-surgery , FMPS , FMBS , PI , GI , PPD , PAL and radiographic IBD and IBA were assessed . The difference between each follow-up and baseline , and between groups at each follow-up was evaluated for the above parameters by st and ard statistical methods . RESULTS In both groups , clinical and radiographic parameters were improved at either 12 or 24 months when compared with baseline . The test group displayed better outcomes when compared with the control group for IBD , PPD , and PAL gain at 12 months , and only for PAL and IBD gain at 24 months . No adverse event related to the use of EMD was reported . CONCLUSIONS The surgical procedure used in the present study , aim ing for maximum preservation of the regenerative potential of periodontal tissues , showed per se excellent results . The use of EMD as an adjunct to periodontal surgery in the treatment of angular defects possibly enhances periodontal regeneration rate OBJECTIVE Casein phosphopeptide-amorphous calcium phosphate nanocomplexes ( CPP-ACP ) exhibit anticariogenic potential in laboratory , animal and human experiments . The remineralising potential of synthetic CPPs on early enamel caries was investigated . DESIGN In vivo study . SETTING University of Naples ' Federico II ' , School of Dentistry , Department of Paediatric Dentistry , 2010 , Italy . PARTICIPANTS 40 volunteers ( age range 10 - 16 years ) were recruited and divided in two groups of 20 ( Group A and B ) . INTERVENTIONS In Group A subjects two demineralised enamel specimens were placed on the buccal surfaces of the first molars and subjects were instructed to apply a commercial product containing CPPs ( GC Tooth Mousse ) only on the right-sided specimen and a placebo mousse on the left , for 1 month . In Group B subjects two enamel specimens were similarly placed into the mouth and used as controls . RESULTS SEM analysis revealed a diffuse and homogeneous mineral coating , reducing the surface alterations only in the demineralised specimens treated with synthetic CPPs into the mouth . CONCLUSIONS Results demonstrate that CPPs are able to promote remineralisation of early enamel lesions OBJECTIVES Application of the guided tissue regeneration ( GTR ) principle and utilization of enamel matrix derivative ( EMD ) have both been shown to result in periodontal regeneration . While clinical investigations have demonstrated that the use of a microsurgical concept in combination with the GTR technique positively affects the percentage of primary closure and the amount of tissue preservation , no such information is available for EMD-treated periodontal defects . It was the aim of the present investigation to assess the clinical effect of the microsurgical access flap and EMD treatment with an emphasis on the evaluation of early wound healing . MATERIAL AND METHODS Eleven patients displaying at least one pair of intrabony periodontal defects with an intrabony component of > or =3 mm participated in the study . At baseline and at 6 and 12 months after surgery , the following clinical parameters were assessed by a blinded examiner : oral hygiene status ( API ) , gingival inflammation ( BOP ) , probing pocket depth ( PPD ) , clinical attachment level ( CAL ) and gingival recession ( GR ) . Defects were r and omly assigned to test or control treatment , which both consisted of a microsurgical access flap procedure design ed for maximum tissue preservation . The exposed root surfaces of the test sites were conditioned with a 24 % EDTA gel followed by EMD ( Emdogain(R ) ) application . Primary flap closure was achieved by a 2-layered suturing technique . Postoperative healing was evaluated by a newly introduced early wound-healing index ( EHI ) at 1 and 2 weeks after surgery . RESULTS Both test and control treatment result ed in a statistically significant mean CAL gain of 2.8 and 2.0 mm at 6 months , and 3.6 and 1.7 mm at 12 months , respectively ( p<0.05 ) . Differences in CAL gain between the two treatment modalities were statistically significant at both time points ( p<0.05 ) . Additional GR values after 12 months averaged 0.3 and 0.4 mm for test and control sites , respectively , and did not reach statistical significance ( p > or = 0.05 ) . Two weeks after surgery , primary closure was maintained in 89 % of the test sites and in 96 % of the control sites . CONCLUSION Both treatment modalities using the microsurgical flap procedure result ed in a high percentage of primary flap closure and maximum tissue preservation . In terms of PPD reduction and CAL gain , the combination with EMD application appeared to be superior to the microsurgical access flap alone BACKGROUND Several studies have documented the clinical efficacy of guided tissue regeneration ( GTR ) with non-resorbable exp and ed polytetrafluoroethylene ( ePTFE ) membranes and enamel matrix proteins ( EMP ) in the treatment of infrabony defects . The objective of this controlled clinical study was to compare the clinical outcomes of 3 surgical modalities in the treatment of deep interproximal infrabony defects . METHODS Ninety ( 90 ) defects in 90 healthy subjects affected by chronic periodontitis were assigned to 1 of 3 treatment groups by blocking to prognostic variables . The test group was treated with the application of EMP and the simplified papilla preservation ( SPP ) technique ; the second group was treated with titanium-reinforced ePFTE membranes and the SPP technique ; and the third group was treated with the SPP technique used as access flap control procedure . No differences were observed in terms of baseline oral hygiene and defect characteristics among the 3 groups , indicating that the blocking approach was effective . A stringent infection control program was adopted for 1 year . RESULTS The 1-year results indicated that : 1 ) all treatment modalities result ed in clinical ly significant improvements in clinical attachment levels ( CAL ) and reduction in probing depth ( PD ) ; 2 ) a statistically significant treatment effect was demonstrated comparing the EMP test , the membrane control , and the flap control groups in terms of CAL gains ; 3 ) both the EMP test and the membrane control groups showed significant CAL gains compared to the flap control group ; 4 ) a statistically significantly greater amount of CAL gain was demonstrated in GTR-treated compared to EMP-treated patients ; 5 ) deeper residual probing depths but smaller increases in gingival recession were demonstrated following EMP therapy ; and 6 ) smoking habits reduced the clinical outcomes of both regenerative procedures . CONCLUSIONS The use of a regenerative procedure is indicated in the treatment of deep vertical bony defects since both the regenerative techniques ( GTR and EMD ) in the present study result ed in clinical ly and statistically significant improvements in clinical parameters compared to the access flap procedure . The use of EMP can be helpful in esthetically-sensitive sites and in reducing patient morbidity BACKGROUND This r and omized , double-masked , placebo-controlled clinical trial evaluated the effect of enamel matrix derivative ( EMD ) on clinical and radiographic parameters of periodontal intrabony defects . METHODS A split-mouth design was used in 16 chronic periodontitis patients who had similar defects ( > or = 6 mm of probing depth ) . Both groups underwent scaling and root planing and were acid-etched with EDTA . The test sites received the EMD solution and the controls a placebo . Clinical examinations of all 16 patients and radiographs of 14 patients were available at baseline and 6 and 12 months after surgery . Clinical outcomes included probing depth ( PD ) and clinical attachment level ( CAL ) ; radiographic analysis was performed using computerized linear measurements . Intergroup comparisons were performed by paired sample s t test , and over time comparisons were made by general linear model ( alpha = 0.05 ) . RESULTS A statistically significant improvement over time for PD and CAL and a decrease of the vertical component of the defect was detected in both groups . Comparisons between groups revealed at baseline a mean+/-SD value of CAL of 12.93+/-2.00 and 13.47+/-2.93 for test and control groups , respectively . These values decreased to 10.92+/-1.92 and 11.31+/-1.86 after 12 months for test and control . No statistically significant differences could be observed between groups . PD displayed similar results from 7.57+/-1.02 and 7.38+/-1.16 for test and control groups at baseline to 3.40+/-1.82 and 2.99+/-1.07 after 12 months . If the data are divided into smokers and non-smokers , no differences are observed . CONCLUSION Use of EMD did not result in more improvement in clinical and radiographic parameters compared to the placebo BACKGROUND Various clinical studies have demonstrated that applying commercially available enamel matrix proteins ( EMP ) on the instrumented root surface during access flap surgery promotes clinical ly significant gains of clinical attachment and bone in intrabony defects . The aim of the present controlled clinical trial was to evaluate the adjunctive effect of filling the intrabony lesion with bovine porous bone mineral ( BPBM ) to a simplified papilla preservation ( SPP ) flap and EMP surgical procedure . METHODS Sixty deep interproximal intrabony lesions in 60 patients with chronic periodontitis were treated with the SPP flap and EMP . In the 30 test defects , the intrabony component was filled with BPBM particles previously reconstituted with the EMP gel . A stringent infection control program was adopted for 1 year . The clinical and radiographical reevaluation was made 1 year after surgery . RESULTS Both techniques result ed in clinical ly and statistically significant improvements between baseline and 1 year , in terms of clinical attachment level ( CAL ) gain , probing depth ( PD ) reduction , and radiographic bone fill ; however , the BPBM test treatment showed statistically significantly greater CAL ( 5.8 + /- 1.1 versus 4.9 + /- 1.0 ) and radiographic bone ( DEPTH ) level gains ( 5.3 + /- 1.1 versus 4.3 + /- 1.5 ) , and less increase in gingival recession ( 0.4 + /- 0.6 versus 0.9 + /- 0.5 ) than the control surgical procedure . CONCLUSION The present study data supported the hypothesis that the adjunctive use of BPBM in grafting intrabony defects has the ability to improve clinical and radiographical outcomes achievable with EMP alone Aims and Objectives : The purpose of the study was to evaluate and compare the microhardness of enamel after the application of anticay on bleached enamel with fluoride containing and fluoride free bleaching agent . Material s and Methods : Twenty freshly extracted teeth decoronated and divided mesiodistally into two halves were r and omly divided into five groups with 10 sample s in each group . The enamel surface was treated as follows : Group 1 - no treatment , Group 2 - fluoride free bleaching agent , Group 3 - fluoride containing bleaching agent , and Group 4 - fluoride free bleaching agent followed by anticay application . The sample s were subjected to indentation to test the microhardness using Vicker 's hardness analyzer . Conclusion : Enamel microhardness significantly increased in sample s where anticay was used after the application of bleaching agent Background and aims . This in vitro study was design ed to evaluate the effect of composite resin types and orthodontic debonding pliers on the amount of adhesive remnants and enamel damages using a novel method of measurement . Material s and methods . 120 extracted human premolars were r and omly divided into four groups ( n = 30 ) . The st and ard edgewise metallic brackets were bonded to the teeth with light-cured composite resin “ Transbond XT ” in the first and second groups , and No-mix composite resin “ Unite ” in the third and fourth groups . Bracket debonding was carried out with Lift Off Debonding Instrument “ LODI ” ( 3 M Unitek ) in the first and third groups , and with Bracket Removing Pliers ( Dentaurum ) in the second and forth groups . yStereomicroscopic evaluation was performed by unbiased sterelogy . All teeth were evaluated for the amount of adhesive remnants and the number and length of enamel cracks . The obtained data on each step was analyzed by two-way ANOVA , chi-square , Wilcoxon , and Kruskal-Wallis . Results . Teeth in group 4 had the lowest adhesive remnants on the enamel surface ( p < 0.01 ) ; and the highest increase in the number of enamel cracks ( p < 0.01 ) among the groups . In addition , groups bonded with Unite showed the highest increase in the length of enamel cracks . Conclusion . Dentaurum debonding pliers with sheer – peel force , when used with the Unite adhesive ( group 4 ) , decreased the amount of adhesive remnants on the enamel surface while it increased enamel damages PURPOSE The aim of this study was to evaluate the clinical success potential of two nanocomposites placed in posterior teeth using an antibacterial adhesive system over 18 months . METHODS A total of 49 Class I and 47 Class II restorations were placed in the permanent teeth of thirty adult patients . The carious lesions were restored with Gr and io ( Voco ) or Filtek Supreme ( 3 M ESPE ) using a two-step self-etching antibacterial adhesive system Clearfil Protect Bond ( Kuraray ) . The restorations were finished with fine-grit diamond burs , Enhance polishing system , and Sof-Lex finishing brushes . The restorations were evaluated at baseline , 6 , 12 , and 18 months after placement using modified Ryge criteria for color stability , marginal discoloration , marginal adaptation , caries formation , anatomic form , postoperative sensitivity , surface roughness , and retention . RESULTS The changes in the parameters were assessed using the Cochran Q test and the McNemar test at a significance level of p < 0.05 . All restorations were classified as clinical ly satisfactory after 18 months . Statistical analysis demonstrated differences only in superficial roughness , with Gr and io exhibiting more surface roughness than Filtek Supreme ( p < 0.05 ) . CONCLUSION Posterior restorations built up with the novel nanocomposites using an antibacterial self-etching system showed satisfactory results at the 18-month recall appointment relative to all criteria except the surface texture in the case of Gr and io . Further evaluations are necessary for a more in-depth analysis BACKGROUND It has been shown that clinical improvement of intrabony periodontal defects can be achieved with the use of enamel matrix proteins ( EMPs ) or by grafting with bovine porous bone mineral ( BPBM ) . There is no report on the potential synergistic effect of EMPs and BPBM in periodontal regenerative therapy . The purpose of this study was to compare the clinical effectiveness of EMPs used alone or in combination with BPBM in the treatment of periodontal intrabony defects in humans . METHODS Twenty-one paired intrabony defects were surgically treated using a split-mouth design . Intrabony defects were treated either with enamel matrix proteins ( EMP group ) or with enamel matrix proteins combined with bovine porous bone mineral ( EMP/BPBM group ) . Re-entry surgeries were performed at 6 months . RESULTS Preoperative probing depths , attachment levels , and transoperative bone measurements were similar for the EMP and EMP/BPBM groups . Postsurgical measurements taken at 6 months revealed a significantly greater reduction in probing depth in the EMP/BPBM group ( 3.43 + /- 1.32 mm on buccal sites and 3.36 + /- 1.35 mm on lingual sites ) when compared to the EMP group ( 1.91 + /- 1.42 mm on buccal sites and 1.85 + /- 1.38 mm on lingual sites ) . The EMP/BPBM group also presented with significantly more attachment gain ( 3.13 + /- 1.41 mm on buccal sites and 3.11 + /- 1.39 mm on lingual sites ) than the EMP group ( 1.72 + /- 1.33 mm on buccal sites and 1.75 + /- 1.37 mm on lingual sites ) . Surgical re-entry of the treated defects revealed a significantly greater amount of defect fill in favor of the EMP/BPBM group ( 3.82 + /- 1.43 mm on buccal sites and 3.74 + /- 1.38 mm on lingual sites ) as compared to the EMP group ( 1.33 + /1.17 mm on buccal sites and 1.41 + /- 1.19 mm on lingual sites ) . CONCLUSIONS The results of this study indicate that BPBM has the ability to augment the effects of EMPs in reducing probing depth , improving clinical attachment levels , and promoting defect fill when compared to presurgical levels The purpose of this study was to examine the effects of ultrasonic orthodontic bracket removal and cleanup and compare them with conventional debonding and cleaning of the enamel surfaces with burs and polishing disks . The amount of enamel loss and time for bracket removal and clean-up were also addressed . Thirty extracted human premolars were collected . The teeth were r and omly placed in one of the three debonding groups : debonding with orthodontic pliers and enamel clean-up with finishing burs and polishing disks ( group 1 ) , debonding with orthodontic pliers and ultrasonic clean-up of the enamel surface ( group 2 ) , and ultrasonic debonding enamel clean-up ( group 3 ) . The teeth were stored for 48 hours in 100 % humidity before bracket removal . All brackets were then removed . Polyvinyl siloxane impressions were made before and after bracket removal . Direct measurements of the teeth in micrometers were made at all steps . An additional 30 teeth were similarly prepared , and the brackets were debonded and cleaned-up as in the three groups previously described . The total time for bracket removal and enamel clean-up for each group was recorded in seconds . ( ABSTRACT TRUNCATED AT 250 WORDS The aim of this prospect i ve multicenter controlled clinical study was to evaluate the efficacy of Emdogain ( Biora ) , an enamel matrix derivative ( EMD ) , when combined with surgical treatment of periodontal angular defects , as compared to surgery alone , for up to 24 months of follow-up . The study was performed at six Italian universities and 11 private practice s. Patients with one- , two- , or three-wall angular defects were enrolled if intrabony defect depth ( IBD ) was 4 mm or more and probing pocket depth ( PPD ) was at least 6 mm . They were r and omly allocated to either test or control groups . The test group was treated by the simplified papilla preservation ( SPP ) flap plus Emdogain after root conditioning with ethylenediaminetetraacetic acid . The control group was treated by SPP alone .  Plaque Index , Gingival Index , PPD , and periodontal attachment level ( PAL ) at surgical sites were assessed at the presurgical examination ( baseline ) . IBD was measured intraoperatively after debridement . IBD was also evaluated with a computer-aided technique , from periapical radiographs . Plaque Index , Gingival Index , PPD , PAL , and IBD were assessed at 12 and 24 months postsurgery . Data were further divided in two subgroups according to baseline IBD ( 6 mm or less and more than 6 mm ) . The differences between each follow-up and baseline , and between groups at each follow-up , for the above parameters were evaluated by st and ard statistical methods . One hundred fifty-three patients were recruited , accounting for 195 intrabony defects : 83 patients ( 108 defects ) and 70 patients ( 87 defects ) were allocated to the test and control groups , respectively . All parameters were improved at both 12 and 24 months , compared to baseline in both groups . In the test group , IBD , PPD , and PAL at 12 months were significantly better than these parameters in the control group . The test subgroup with IBD of more than 6 mm at baseline displayed a better outcome when compared to the 6 mm or less IBD subgroup . No significant adverse events related to the use of Emdogain were reported . The use of EMD as an adjunct to periodontal surgery in the treatment of angular defects significantly enhanced the rate and degree of periodontal regeneration . The control group also displayed significant tissue regeneration , but at a slower rate compared to the Emdogain group . The surgical procedure itself , with its goal of maximum preservation of the regenerative potential of periodontal tissues , proved to be effective in the treatment of periodontal angular defects . Pockets with IBD greater than 6 mm showed major improvement when treated with Emdogain 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 OBJECTIVES The purpose of this study was to compare microleakage of Class V restorations following acid , laser or laser and acid treatment of cavity walls . METHODS St and ardized lingual and buccal Class V preparations were made in 18 human extracted third molars . The preparations were r and omly assigned to three equal groups ( n=12 ) . Group 1 : cavities were treated with 35 % phosphoric acid . Group 2 : cavities were irradiated with an Er-YAG laser at 2Hz and 250mJ on dentin and 300mJ on enamel , with water cooling . Group 3 : cavities were irradiated with the laser before acid etching . Scotchbond 1 Adhesive System and Z100 resin composite were used for restorations . The specimens were stored in water for 24h at 37 degrees C and thermally cycled ( 500x ) between 6 - 60 degrees C. After 24h immersion in 0.5 % basic fuchsin , dye penetration was recorded according to an ordinal scale . Data were analysed using non-parametric statistical tests ( Kruskal-Wallis and Mann-Whitney ) . RESULTS On the occlusal walls , microleakage in acid etched cavities was significantly lower than that achieved after laser treatment ( P<0.001 ) or after both treatments ( P<0.05 ) . On the gingival walls , no statistical differences were found . SIGNIFICANCE Laser irradiation of enamel is not a valid alternative to acid-etching pretreatment for resin composite material s adhesion . Acid etching alone gave the lowest microleakage at the occlusal margin . No differences were found for microleakage on gingival wall , although lased dentin surfaces presented several characteristics that appear to be advantageous for bonding BACKGROUND Surgical periodontal treatment with enamel matrix protein derivative ( EMD ) has been shown to promote periodontal regeneration . However , it is not known whether nonsurgical periodontal therapy with additional subgingival application of EMD may also enhance periodontal regeneration . The purpose of this study was to clinical ly and histologically evaluate healing of human intrabony defects following non-surgical periodontal treatment with and without application of EMD . METHODS Sixteen patients , each of whom displayed one advanced intrabony defect around teeth or roots scheduled for extraction , were included in the study . The defects were treated as follows : 1 ) scaling and root planing with h and instruments and application of EMD ; 2 ) scaling with an ultrasonic instrument and application of EMD ; or 3 ) scaling with an ultrasonic instrument alone .  Healing was uneventful in all cases . Six months after surgery , the teeth or roots were extracted together with some of their surrounding soft and hard tissues and processed for histologic evaluation . RESULTS Clinical examination revealed a probing depth reduction and a gain of clinical attachment after all 3 treatment modalities . The histological evaluation , however , revealed that healing in all 3 procedures was predominantly characterized by formation of a long junctional epithelium along the instrumented root surface and no predictable regeneration of attachment apparatus . CONCLUSION Within its limits , the present study failed to show periodontal regeneration in advanced human intrabony defects following non-surgical treatment with subgingival application of EMD
Conclusions There is weak evidence indicating length and width of EMCs increase following bracket removal and the scientific evidence concerning quantitative evaluation of the number parameter before and after debonding is insufficient .
However , there is a strong evidence that after debonding the number of EMCs is likely to increase .
Objectives To evaluate and compare the enamel microcracks ( EMCs ) characteristics ( qualitative and quantitative ) in the form of tooth damage before and after debonding from human teeth of in vitro studies .