Title

Optimal Post-Bleaching Time Before Placement of Composite Resin Restorations

Clinical Question

Following a cycle of at-home bleaching by a patient using a custom bleaching tray with carbamide peroxide, what is the optimal length of time to wait before placing resin composite restorations that will ensure no clinically significant reduction in shear bond strength to dentin or enamel.

Clinical Bottom Line

There is conflicting data on what the optimal time period post-bleaching should be to avoid reducing the effective bond strength of the restoration. Based on the most current evidence, carbamide peroxide solutions require only 1 day of “rest” versus bleaching with hydrogen peroxide gel (35%) should be given a 7- day rest period. Since none of these studies accurately reproduce the exact conditions of a true clinical situation, it may still be advisable to follow the more conservative guidelines of one to two weeks following any type of bleaching unless the situation does not allow. (See Comments on the CAT below)

Best Evidence

PubMed ID	Author / Year	Patient Group	Study type (level of evidence)
20178218	Barbarosa/2009	80 enamel samples 80 dentin samples 20 volunteers	Randomized clinical trial
Key results	There were no significant differences with regards to the time span for the enamel and dentin groups (P > 0.05). It was concluded that restorative procedures may be performed immediately after the end of the bleaching treatment.
20194386	Bittencourt/2010	20 volunteers	Randomized Clinical Trial
Key results	The authors found that 35 percent hydrogen peroxide reduces the bond strength to enamel and dentin and that it is necessary to wait seven days before performing adhesive restorative procedures. CLINICAL IMPLICATIONS: The results of this study suggest that clinicians should allow seven days to elapse after completion of in-office bleaching with 35 percent hydrogen peroxide before placing adhesive restorations.
17626292	Unlu/2008	135 Samples	Bench-top Lab study
Key results	The results of this study proved that immediate bonding of composite to enamel bleached with 10% carbamide peroxide (CP) and 35% hydrogen peroxide (HP) gels result in a significant decrease in shear bond strength. It is advisable that composite resin application onto bleached enamel surfaces should be delayed at least 24 h for 10% CP and 1 week for 35% HP.

Evidence Search

Search was limited to clinical trial, meta-analysis or randomized controlled trial in English. The Mesh search terms used were “tooth bleaching”, “composite resins” combined with a pubmed search for “shear bond strength” and “elapsed time.”

Comments on
The Evidence

There were numerous examples of clinical trials researching this subject with various methods, some in situ and some bench top studies. Many of these studies contradicted each other, so care was taken to choose the most recent evidence with the greatest significance.

Applicability

Applicable to any restorative dentistry case involving bleaching and esthetic concerns.

Specialty

(General Dentistry) (Restorative Dentistry)

Keywords

composite resins, shear bond strength, tooth bleaching

ID#

612

Date of submission

04/07/2010

E-mail

bushong@livemail.uthscsa.edu

Author

Perry Bushong

Co-author(s)

Co-author(s) e-mail

Faculty mentor

Charles Hermesch, DMD

Faculty mentor e-mail

HERMESCH@uthscsa.edu

Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)

None available

Comments and Evidence-Based Updates on the CAT
(FOR PRACTICING DENTISTS', FACULTY, RESIDENTS and/or STUDENTS COMMENTS ON PUBLISHED CATs)

by Kennon Koenig (San Antonio, Texas) on 08/29/2013
I conducted a pubmed search on this topic in August 2013 and found more recent publications: PMID 22048584, 22645730 , and 22144802. These studies showed that the use of sodium ascorbate hydrogel allowed for the immediate bonding of composite resins to bleached enamel. Although these studies do not directly answer the question, they do offer some clinical significance to the question.