Chemical treatment of cavity walls following manual excavation of carious dentin.
OBJECTIVE
To improve the conditioning of cavity walls resulting from minimal mechanical preparation of carious lesions, such as is done in modified Class II tunnel preparations.


METHODS
Proximal carious lesions in premolars and molars were excavated manually and the cavity walls studied using a stereomicroscope and by scanning electron microscopy (SEM) following treatment with either polyacrylic acid, sodium hypochlorite, the enzyme preparation Pronase, or sequential combinations of the agents. Polyacrylic acid (10%) was used according to the manufacturer's instructions, while concentrated sodium hypochlorite (5.25%) was applied with either intermittent scrubbing or with ultrasonic energy for 5-10 minutes, or the cavity wall was incubated with the agent at +/- 37 degrees C for periods up to 24 hours. Incubation with the proteolytic enzyme preparation Pronase was carried out at 37 degrees C for a period up to 48 hours.


RESULTS
Manual excavation did not remove all carious dentin, neither did treatment with polyacrylic acid. Scrubbing or sonication with ample amounts of sodium hypochlorite, followed by treatment with polyacrylic acid, or prolonged incubation with sodium hypochlorite, removed most of the remaining carious dentin. However, the "cleanest" surfaces were obtained after 48 hours of incubation with Pronase. Spots of thicker, soft layers of decayed dentin that were left intentionally at some locations could be disintegrated only by the Pronase treatment. It was concluded that treatment with sodium hypochlorite and polyacrylic acid in tandem, or with Pronase may represent potential supplements to conventional cavity cleaning that deserve further investigation. In the clinic more efficient cavity cleaning may improve the bonding ability and thus reduce the risk of marginal ridge fracture in teeth with Class II tunnel restorations.
Nordbø
H
H
Department of Preclinical Techniques and Material Sciences, School of Dentistry, University of Oslo, Norway.
Brown
G
G
Tjan
A H
AH
D000180:Acrylic Resins / Q000627:therapeutic use; D003731:Dental Caries / Q000473:pathology / Q000628:therapy*; D003737:Dental Cavity Preparation / Q000379:methods*; D019551:Dental Disinfectants / Q000627:therapeutic use; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D003902:Detergents / Q000627:therapeutic use; D006801:Humans; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D011402:Pronase / Q000627:therapeutic use; D012973:Sodium Hypochlorite / Q000627:therapeutic use
D000180:Acrylic Resins; D019551:Dental Disinfectants; D003902:Detergents; C006903:carbopol 940; D012973:Sodium Hypochlorite; D011402:Pronase