Key messages
- Lasers may slightly reduce pain after 24 hours. They may reduce pain beyond 24 hours but the evidence is very uncertain.
- Lasers do not appear to cause adverse (unwanted) effects.
- We need future studies to strengthen the evidence and investigate the impact of laser treatment on quality of life.
What causes tooth hypersensitivity?
Tooth hypersensitivity is short, sharp pain that is not due to a dental disease or problem such as caries (holes in the teeth) and can occur when teeth come into contact with hot or cold food or drinks; cold air; or specific food or drinks such as sugar and fizzy (carbonated) drinks. It can also occur when people brush their teeth or receive professional dental care.
How can we treat tooth hypersensitivity?
An option for treating tooth hypersensitivity is to use laser (light) therapy. Lasers produce a narrow, focused beam of light that is applied to the painful tooth to treat it. Depending on the type of laser used, the treatment either aims to seal off the painful area, or to numb it.
What did we want to find out?
We wanted to find out if lasers work to treat tooth hypersensitivity, and whether they are associated with any unwanted (adverse) effects.
What did we do?
We searched for studies that compared lasers against a placebo (dummy treatment) or no treatment for treating tooth hypersensitivity. We compared and summarized the results of the studies and rated our confidence in the evidence, based on factors such as study methods and sizes.
What did we find?
We found 23 studies of different durations up to 6 months that involved 936 people (2296 teeth) over 12 years of age with tooth hypersensitivity.
The evidence:
- suggests that lasers may slightly reduce pain after 24 hours compared to placebo or no treatment;
- is not robust enough to determine if lasers reduce pain beyond 24 hours or not; and
- suggests that lasers do not cause unwanted effects.
No studies investigated the impact of laser treatment on people’s quality of life.
What are the limitations of the evidence?
The main limitations of the evidence are that studies:
- reported inconsistent results;
- were conducted in ways that may have introduced errors into their results; and
- produced imprecise results when they were combined together.
Due to these limitations, we have little confidence in the evidence.
How up to date is this evidence?
The evidence is up to date to October 2020.
Limited and uncertain evidence from meta-analyses suggests that the application of laser overall may improve pain intensity when tested through air blast or tactile stimuli at short, medium, or long term when compared to placebo/no treatment. Overall, laser therapy appears to be safe. Future studies including well-designed double-blinded RCTs are necessary to further investigate the clinical efficacy of lasers as well as their cost-effectiveness.
Dentinal hypersensitivity is characterized by short, sharp pain from exposed dentine that occurs in response to external stimuli such as cold, heat, osmotic, tactile or chemicals, and cannot be explained by any other form of dental defect or pathology. Laser therapy has become a commonly used intervention and might be effective for dentinal hypersensitivity.
To assess the effects of in-office employed lasers versus placebo laser, placebo agents or no treatment for relieving pain of dentinal hypersensitivity.
Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 20 October 2020), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2020, Issue 9), MEDLINE Ovid (1946 to 20 October 2020), Embase Ovid (1980 to 20 October 2020), CINAHL EBSCO (Cumulative Index to Nursing and Allied Health Literature; 1937 to 20 October 2020), and LILACS BIREME Virtual Health Library (Latin American and Caribbean Health Science Information database; from 1982 to 20 October 2020). Conference proceedings were searched via the ISI Web of Science and ZETOC, and OpenGrey was searched for grey literature. The US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases.
Randomized controlled trials (RCTs) in which in-office lasers were compared to placebo or no treatment on patients aged above 12 years with tooth hypersensitivity.
Two review authors independently and in duplicate screened the search results, extracted data, and assessed the risk of bias of the included studies. Disagreement was resolved by discussion. For continuous outcomes, we used mean differences (MD) and 95% confidence intervals (CI). We conducted meta-analyses only with studies of similar comparisons reporting the same outcome measures. We assessed the overall certainty of the evidence using GRADE.
We included a total of 23 studies with 936 participants and 2296 teeth. We assessed five studies at overall low risk of bias, 13 at unclear, and five at high risk of bias. 17 studies contributed data to the meta-analyses. We divided the studies into six subgroups based on the type of laser and the primary outcome measure. We assessed the change in intensity of pain using quantitative pain scale (visual analogue scale (VAS) of 0 to 10 (no pain to worst possible pain)) when tested through air blast and tactile stimuli in three categories of short (0 to 24 hours), medium (more than 24 hours to 2 months), and long term (more than 2 months).
Results demonstrated that compared to placebo or no treatment the application of all types of lasers combined may reduce pain intensity when tested through air blast stimuli at short term (MD -2.24, 95% CI -3.55 to -0.93; P = 0.0008; 13 studies, 978 teeth; low-certainty evidence), medium term (MD -2.46, 95% CI -3.57 to -1.35; P < 0.0001; 11 studies, 1007 teeth; very low-certainty evidence), and long term (MD -2.60, 95% CI -4.47 to -0.73; P = 0.006; 5 studies, 564 teeth; very low-certainty evidence). Similarly, compared to placebo or no treatment the application of all types of lasers combined may reduce pain intensity when tested through tactile stimuli at short term (MD -0.67, 95% CI -1.31 to -0.03; P = 0.04; 8 studies, 506 teeth; low-certainty evidence) and medium term (MD -1.73, 95% CI -3.17 to -0.30; P = 0.02; 9 studies, 591 teeth; very low-certainty evidence). However, there was insufficient evidence of a difference in pain intensity for all types of lasers when tested through tactile stimuli in the long term (MD -3.52, 95% CI -10.37 to 3.33; P = 0.31; 2 studies, 184 teeth; very low-certainty evidence).
Most included studies assessed adverse events and reported that no obvious adverse events were observed during the trials. No studies investigated the impact of laser treatment on participants' quality of life.