Effect of Cavity Disinfection
At the end of 6 weeks, the diastemas had closed sufficiently to warrant bracket removal (Fig.3). The brackets were removed in a twisting manner with a 095-Sbracket remover (OrthoPliCorporation, Philadelphia, PA). The six maxillary anterior teeth underwent cosmetic contouring; impressions were taken and Cerinate porcelain laminates (Den-Mat Corporation) were luted in place using Ultrabond bonding composite (Den-Mat Corporation) (Fig.4). The patient expressed his pleasure over the elimination of the diastema and the creation of a "new,beautiful smile."The patient has been observed on 6-month recall visits. The diastema closure has been successfully maintained and stabilized due to the close contacts of the approximating laminate surfaces. Thus, two modalities
of treatment, orthodontics and laminate placement, combined to achieve an excellent esthetic effect that eliminated a long-lasting cosmetic problem.
REFERENCES SchlossbergA. Adult tooth movement in general dentistry. Philadelphia, PA: WB Saunders. 1975. Ramfjord SP, Ash MM. Occlusion. Philadelphia, PA: WB Saunders, 1966. Lombardi RE. A method for the classification of errors in dental esthetics. J Prosthet Dent 1974; 32:501. RennerW. An introduction to dental anatomy and esthetics. Chicago, I L Quintessence, 1985.
Effect of Cavity Disinfection on Bond Strength to Dentin A. John Gwinnett, Ph.D., B.D.S., L.D.S.R.C.S., F.A.D.M.*
The application of a disinfecting step in cavity preparation and tooth restoration is gaining wider acceptance. This study examined the effect of two commercially
available disinfecting agents on the shear bond strength to dentin using a fourth generation dentin bonding agent. The agent tested permitted an evaluation of both dry and wet bonding techniques. It was found that the commercial preparations did not adversely affect shear bond strength to dentin in either the dry or wet application.
everal have demonstrated a relationship between postoperative pulpal pathology and bacterial infection. Acute and chronic inflammatory pulpal responses, previously attributed to restorative rnateria l ~ ,have ~ . ~been shown to have etiology in microleakage at the restoration interface and the existence of bacterial ~ontamination.~.~ The smear layer,8 a narrow zone of superficially altered tissue associated with cavity preparation, is commonly infected with bacteria and provides a safe haven for their propagation. Cavity debridement is intended to cleanse the preparation, but Brannstromgrecognizedthe need to disinfect
it also and developed an antimicrobial preparation containing benzylkonium chloride specifically for that purpose. Published reports and textbooks dealing with operative technique seldom mention or even acknowledge the need for cavity disinfection. Cut mineralized dental tissues are not usually regarded with the same measure of concern as that held for managing incised soft tissue wounds. However,there are agrowing number of clinicians who are now anecdotally cavity disinfection. Recent s t ~ d i e s ~demonstrated ~,'~ that a disinfecting agent might be incorporated into formulations used in the bonding procedure. With significant advances in bonding restorative materials to mineralized dental tissues, it has become necessary to determine the effect, if any, of disinfecting *Professor. Department of Oral Biology & Pathology, School of Dental agents on the bond at the tissue/restoration interface. Medicine. SUNY at Stony Brook, Stony Brook. New York Addressreprhtrequeststo AJohnCwlnnett.Ph.D..B.D.S..L.D.S.RC.S.. The purpose of this study was to determine the shear F.A.D.M.. Professor.Departmentoforal Biology &Pathology.School ofDental bond strength to dentin using a fourth generation Medicine. Health Sciences Center--SouthCampus,State University of New bonding agent involvingtreatment with two commercialYork at Stony Brook. Stony Brook. NY 11794-6702 0 1992 Decker Periodicals Inc. ly available agents recommended for cavity disinfection.
JOURNAL OF ESTHETIC DENTISTRY VOLUME 4, SUPPLEMENT 1992
pen recorder. The values at failure were converted to MPa units with means and standard deviations calculated. The data were analyzed statistically using ANOVA and the Student t-test for significance.
MATERIALS AND METHODS Six groups were established each containing ten caries-free,recentlyextracted third molar teeth stored in 70% alcohol prior to use. The crowns were cut transversely at their mid-coronal point to expose the dentin using a water cooled rotating diamond blade. The cut surface was dressed with wet 320 grit silicone carbide paper. The teeth, with roots and pulp tissue intact, were then embedded in die stone in one half of a Watanabe14 jig. The samples were placed in water for 24 hours prior to treatment. The dentin in all groups was conditioned with 10% phosphoric acid for 20 seconds and rinsed with an airwater spray for 10 seconds. Groups 1 and 2 were then treated with Tubulicid Red Label (Global Dental Products, North Bellmore. NY), group 1 as recommended by the manufacturer. This involved a 60-s application followed by blotting with a cotton swab and drying with compressed air (5 s). In Group 2, the drying step was omitted, permitting a n evaluation of wet bonding,I5 a procedure known to favor the "water chasing"behavior16 of certain bonding agents that contain acetone similar to the one used in this study. Groups 3 and 4 were treated with Hibiclens (Coe, Chicago, IL). The manufacturer recommends swabbing the surface, rinsing with water, and further swabbing followed by a final rinse. This procedure was followed and Group 3 was dried for 5 s after the final rinse. Group 4 was simply blotted dry similar to Group 2. The rationale for applying the disinfecting agents after acid conditioning was based on the fact that the smear layer was removed by conditioning making it redundant to disinfect the dentin surface prior to that event. Conditioning exposed the critical underlying tissue to the action of the disinfecting agent. Groups 5 and 6 served as controls in which no disinfecting agent was used. Group 5 was air dried for 5 seconds following rinsing of the conditioner: Group 6 was simply blotted dry. AU-Bond 2 (Bisco, Itasca, IL) primer was applied to each specimen. Several applications were made (6-8 with no drying in between) after which the primer was allowed to stand for 5 seconds followed by a gentle air drying for 10 seconds. A shiny film of primer was obtained on the dentin following which a thin Alm of companion bonding agent was applied with a brush and polymerized for 20 seconds. The remaining half of the Watanabe jig was assembled complete with thin self-adhesive, clear PVC tape. A standard, circular window (0.0714em2) had been punched in the tape to define the test area. P50 (3M Dental Products, St. Paul, MN) was added in three 1-mm increments each being polymerized for 60 seconds. The bonded assemblies were placed in water at 37OC for 24 hours. The assemblies were tested in a shear mode in an Instron machine at a cross-head speed of 5 m m / m untilfailure.The events were monitored on a strip chart.
RESULTS Table 1 illustrates the recorded shear bond strength values. The mean values recorded for the wet bonded specimens were the highest, and when compared with the control, it was statistically evident that n o significant differencewas incurred as a result of the treatment with the disinfecting agents. Although lower values were recorded for the dry bonded specimens, there was no statistically significant difference between the control and the specimens treated with the antibacterial agents. Values recorded for the wet bonded groups were statistically si@icantly higher (p = .05) than those of the dry bonded groups.
DISCUSSION Tubulicid Red Label contains 1% benzylkonium chloride, EDTA, and 1%sodium fluoride in aqueous solution. The high substantivity of this quaternary agent makes it a highly effective bactericide. Hibiclens, a popular antibacterial soap and of higher viscosity than Tubulicid, contains 4% chlorhexidine gluconate. Both antimicrobial agents, as applied, lend themselves to the wet bonding technique and do not compromise shear bond strength to dentin. Other ingredients seem to neither enhance nor detract from the values. Benzylkonium chloride is known to cross link to collagen, but this does not seem to impair hybridization,l7 the micromechanical means of resin bonding upon which All-Bond 2, a fourth generation bonding system, is based. Since resin has been shown to infiltrate the intertubular dentin and the tubules in uiuo to seal the restoration interface, the value of the topical application of bactericide may be questioned. Further studies are needed to establish any efficacy of the disinfecting step in the bonding procedures. Such a position does not deny the advantage of disinfection of the preparation where conventional nonbonding or nontotal etch bonding techniques are used.
Table 1. Shear Bond Strength To Dentin (MPa) Treatment Hlbiclens Tubullcld Control Hlblclens Tubulicid Control
Dry Dry Dry MOM Moist Moist
27.11 f 4.98 26.36 & 9.05 23.26 & 6.30 31.85 f 4.61 31.51 f 5.01 32.68 f 7.12
Bonding Composite to Glass Ionomer
6. BergenholtzG.CoxC, Loeschew, Syed S. Bacterial leakage around dental restorations. Its effect on the dental pulp. J Oral Path01 Med 1982; 11:439450. 7. Cox C. Biocompatibility of dental materials in the absence of infection. Oper Dent 1987; 12:146-152. 8. Gwinnett A J . Smear layer: morphological considerations. Oper Dent 1984; 3(Suppl):3-12. 9. B r h s t r B m M, Nordenvall KJ. Glantz PO. The effect of EDTA containing surface active solutions on the morphology of prepared dentin: a n in uiuo study. J Dent Res 1980; 59:1127-1131. 10. Alex G. Personal communication. 11. Kanca J. Personal communication. 12. Chan DCN, Hui EYW. Antimicrobial action of chlorhexidineincorporated inanetchant. JDentRes 1992; 71:141. (Abstr 284). 13. WadeW, MoranJ, AddyM. Disinfectionofcavitiesusingan antibacterial dentine primer. Med Sci Res 1989; 17:905. 14. Watanabe LG.Lacy AM, Davis DR. Shear bond strength: single plane vs lap shear. J Dent Res 1988: 67:383. (Abstr 2159). 15. Kanca J. Effect of drying on bond strength. J Dent Res 1991; 70:394. (Abstr 1029). 16. Gwinnett AJ. Moist vs dry dentin: its effect on shear bond strength. Am J Dent 1992; 5:127-129. 17. Nakabayashi N. Kajima K, Masuhara E. Promotion of adhesionby infiltration ofmonomers into tooth substrates. J Biomed Mater Res 1982: 16:265-273.
CONCLUSION Application of the antimicrobial solutions Tubulicid Red Label and Hibiclens to phosphoric acid conditioned dentin does not compromise the shear bond strength of All-Bond 2 applied using either a wet or dry method for bonding.
REFERENCES 1. B r h s t r B m M, Nyborg H. The presence of bacteria in cavities filled with silicateand compositematerials. Svensk Tandlakare-Tidskrift 1941; 64:149-155. 2. B r h s t r B m M. Nyborg H. Bacterial growth and pulpal changes under inlays cemented with zinc phosphate cement and Epoxylite CBA 9080. J Prosthet Dent 1974; 31:556-565. 3. B r h s t r B m M. Vojinovic 0, Nordenvall KJ. Bacteria and pulpal reactions under silicate cement restorations. J Prosthet Dent 1979: 41:290-295. 4. Retief H, Austin J, Fatti L. h l p a l response to phosphoric acid. J Oral Path01 Med 1974; 3:114-122. 5. Stanley H. Going R, Chauncey H. Human pulp response to acid pretreatment of dentin and to composite restorations. J Am Dent Assoc 1975; 91:817-825.
Bonding Composite to Glass lonomer with Adhesive Resin Cements Daryl Styner, D.D.S.," Warren Scherer, D.D.S.! James LoPresti, D.D.S.,* and Bapanaiah Penugonda, B.D.S.,M.S. 4
This study was to determine the bond strength of composite to glass ionomer using the following adhesive resin cements: Imperva Dual, CB Metabond, All-Bond, Geristore, and Panavia. All materials were mixed following the manufacturer's specifications. Bonded samples were thermocycled for 2000 x between 5°C and 55°C. Shear bond strengths were determined using a n Instron Testing Machine. No statistical differences were noted between materials at the p c .05 level of signifcance. In addition, scanning electron micrographs were taken of the primed glass ionomer surfaces. These micrographs revealed varying amounts of matrix dissolution along with roughened surface topographies.
lass ionomer cements bond chemically to enamel .-
addition to these DroDerties thev are also biocompatible with tooth struct&-e.;.2As such,"they may be considered to be ideal liner or base for dentinal restoratives.
istration: New York University'college of Dentistry. &w York. New York Address reprlnt requests to Dr. Warren Scherer. New York University College of Dentistry, 345 East 24th Street. New York. NY 10010 8 1992 Decker Periodicals Inc.