Introduction: Debonding of denture teeth from denture bases continues as a problem for wear-resistant denture teeth.  ISO testing methods for tooth-denture assemblies create complex loads, variability in results, and test “toughness” more than tooth-denture “interfacial strengths.”  Objective:  Utilize a micro-tensile bond strength (µTBS) testing to evaluate interfacial bonding of PMMA versus IPN teeth in heat-cured PMMA versus light-cured UDMA denture bases.  Methods:  1-tooth dentures (central incisor, Lucitone-199 denture-base resin, heat-cure, 5 assemblies per flask) were processed with representative combinations of (a) different teeth (PMMA, IPN), (b) surface treatments (none, sandblasting=SB, bur roughening [BR], MMA pretreatment, denture tooth-bonding systems [TBS]), and (c) representative denture-base materials (PMMA, Eclipse UDMA Prosthodontic Resin [Dentsply]).  10 µTBS bars per group (~1x1x30mm) were sectioned from 1-tooth dentures parallel to the tooth long axis and ~90° to the tooth-denture interface and stored (>72h, dry, 25°C) before µTBS testing (E-Z Tester, CHS=0.1mm/min).  Denture bases alone were tested for reference.  Differences (ANOVA, p£0.05, Tukey's post-hoc tests, no shared superscripts) among group means (±sd, MPa) are reported below.  Adhesive-cohesive failure patterns were noted.

Teeth:	---	PMMA	PMMA	PMMA	IPN	IPN	IPN	---
Denture:	PMMA	PMMA	PMMA	PMMA	PMMA	PMMA	UDMA	UDMA
Mech. Tx	---	No	SB	No	No	SB	BR	---
Chem. Tx	---	No	No	MMA	No	No	TBS	---
µTBS (MPa)	46±14ad	45±17ab	66±6bc	69±20ab	57±8ab	73±15bc	50±17ab	59±3ad

Results:  µTBS values were comparable in magnitude to values for dentin bonding systems (~60 MPa).  Results had relatively small sd's making the µTBS approach attractive.  Failures were predominantly interfacial (>55%).  SB or MMA treatments improved µTBS for PMMA, as expected.  UDMA denture-base material was stronger, but with IPN teeth did not produce the highest µTBS values.  Conclusion:  µTBS allowed more careful analysis of tooth-denture interfaces.  Roughened surfaces produced the greatest µTBS values.  Acknowledgment: Supported by Trubyte-Dentsply.