Key messages
- Rinsing with chlorhexidine mouthwash before a dental extraction or beginning 24 hours after may help to prevent a dry socket.
- Placing a chlorhexidine gel directly into the socket immediately after tooth extraction may help to prevent a dry socket.
- Chlorhexidine rinses cause some minor adverse (unwanted) effects; chlorhexidine intrasocket gels do not appear to cause adverse effects.
- Alvogyl reduces the pain of a dry socket when compared to zinc oxide eugenol, but the evidence for this is very uncertain.
- Alvogyl does not appear to cause unwanted effects.
- We need future studies to strengthen the evidence and investigate the best ways to prevent and treat dry socket in all teeth.
What is dry socket?
Dry socket is a painful condition that sometimes arises after a tooth has been extracted and is more likely to occur following extraction of wisdom teeth in the lower jaw.
What causes dry socket?
It is thought to be linked to the loss of some or all of the blood clot that forms at the bottom of a tooth socket after a tooth is taken out.
How can we prevent dry socket?
An option for prevention of dry socket is to reduce debris and the bacterial load in the mouth, though dry socket is not bacterial in origin. People with poor oral hygiene (food debris and plaque) are at greater risk of dry socket. Improved oral hygiene and rinsing before a dental extraction or beginning 24 hours after may reduce the likelihood of dry socket.
How can we treat dry socket ?
Options for treating dry socket largely focus on reducing pain locally around the tooth extraction site by placing an obtundent (a soothing medicated dressing).
What did we want to find out ?
We wanted to find out if antiseptic rinses, gels, or healing patches could help to prevent dry socket. We also wanted to find out if placing a medicated dressing could treat a dry socket and whether any unwanted side effects were produced.
What did we do?
We searched for studies that compared antiseptic rinses or intrasocket gels with a placebo (dummy) rinse or nothing and a placebo (dummy) intrasocket gel or nothing.
To find the best way to treat dry socket we searched for studies that compared different soothing agents with a placebo (dummy) with other soothing agents or with nothing.
We compared the results of the studies and summarised the findings. We made an assessment of our confidence in the evidence based on the design of the study and the number of patients recruited.
What did we find?
We identified 49 trials; 39 trials (6219 participants) investigated prevention of dry socket and 10 trials (552 participants) investigated the treatment of dry socket.
We found that:
- rinsing both before and after tooth extraction (commencing 24 hours after extraction) with chlorhexidine gluconate rinse (at 0.12% and 0.2% strength) probably results in a reduction in dry socket;
- placing chlorhexidine gel (0.2% strength) in the socket of an extracted tooth probably results in a reduction in dry socket;
- chlorhexidine rinses and gels are equally effective at reducing dry socket, but the evidence for this comparison is very uncertain;
- chlorhexidine rinses produced some minor unwanted effects; chlorhexidine intrasocket gels appeared to produce no unwanted effects;
- there was a small amount of evidence of very low certainty from two studies that Alvogyl (old formulation) may reduce pain at day 7 in patients with dry socket when compared to zinc oxide eugenol. This evidence relates to the old formulation of Alvogyl which is no longer available. It should be noted that the formulation of Alvogyl has changed, it is now called Alveogyl.
Tooth extractions are generally undertaken by dentists for a variety of reasons, however, all but five studies included in the present review included participants undergoing extraction of third molars, most of which were undertaken by oral surgeons.
What are the limitations of the evidence?
The main limitation of the evidence are that studies:
- reported mostly on tooth extractions involving lower wisdom teeth;
- were undertaken in ways that introduced errors in the conduct of the study leading to errors in the results; and
- produced imprecise results when they were combined.
Due to these errors we have some confidence in the results relating to chlorhexidine rinses and gels but further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
How up to date is this evidence?
The search for existing studies was completed by 28 September 2021.
Tooth extractions are generally undertaken by dentists for a variety of reasons, however, all but five studies included in the present review included participants undergoing extraction of third molars, most of which were undertaken by oral surgeons. There is moderate-certainty evidence that rinsing with chlorhexidine (0.12% and 0.2%) or placing chlorhexidine gel (0.2%) in the sockets of extracted teeth, probably results in a reduction in dry socket. There was insufficient evidence to determine the effects of the other 21 preventative interventions each evaluated in single studies. There was limited evidence of very low certainty that Alvogyl (old formulation) may reduce pain at day 7 in patients with dry socket when compared to zinc oxide eugenol.
Alveolar osteitis (dry socket) is a complication of dental extractions more often involving mandibular molar teeth. It is associated with severe pain developing 2 to 3 days postoperatively with or without halitosis, a socket that may be partially or totally devoid of a blood clot, and increased postoperative visits. This is an update of the Cochrane Review first published in 2012.
To assess the effects of local interventions used for the prevention and treatment of alveolar osteitis (dry socket) following tooth extraction.
An Information Specialist searched four bibliographic databases up to 28 September 2021 and used additional search methods to identify published, unpublished, and ongoing studies.
We included randomised controlled trials of adults over 18 years of age who were having permanent teeth extracted or who had developed dry socket postextraction. We included studies with any type of local intervention used for the prevention or treatment of dry socket, compared to a different local intervention, placebo or no treatment. We excluded studies reporting on systemic use of antibiotics or the use of surgical techniques because these interventions are evaluated in separate Cochrane Reviews.
We used standard methodological procedures expected by Cochrane. We followed Cochrane statistical guidelines and reported dichotomous outcomes as risk ratios (RR) and calculated 95% confidence intervals (CI) using random-effects models. For some of the split-mouth studies with sparse data, it was not possible to calculate RR so we calculated the exact odds ratio (OR) instead. We used GRADE to assess the certainty of the body of evidence.
We included 49 trials with 6771 participants; 39 trials (with 6219 participants) investigated prevention of dry socket and 10 studies (with 552 participants) looked at the treatment of dry socket. 16 studies were at high risk of bias, 30 studies at unclear risk of bias, and 3 studies at low risk of bias.
Chlorhexidine in the prevention of dry socket
When compared to placebo, rinsing with chlorhexidine mouthrinses (0.12% and 0.2% concentrations) both before and 24 hours after extraction(s) substantially reduced the risk of developing dry socket with an OR of 0.38 (95% CI 0.25 to 0.58; P < 0.00001; 6 trials, 1547 participants; moderate-certainty evidence). The prevalence of dry socket varies from 1% to 5% in routine dental extractions to upwards of 30% in surgically extracted third molars. The number of patients needed to be treated (NNT) with chlorhexidine rinse to prevent one patient having dry socket was 162 (95% CI 155 to 240), 33 (95% CI 27 to 49), and 7 (95% CI 5 to 10) for control prevalence of dry socket 0.01, 0.05, and 0.30 respectively.
Compared to placebo, placing chlorhexidine gel intrasocket after extractions reduced the odds of developing a dry socket by 58% with an OR of 0.44 (95% CI 0.27 to 0.71; P = 0.0008; 7 trials, 753 participants; moderate-certainty evidence). The NNT with chlorhexidine gel (0.2%) to prevent one patient developing dry socket was 180 (95% CI 137 to 347), 37 (95% CI 28 to 72), and 7 (95% CI 5 to 15) for control prevalence of dry socket of 0.01, 0.05, and 0.30 respectively.
Compared to chlorhexidine rinse (0.12%), placing chlorhexidine gel (0.2%) intrasocket after extractions was not superior in reducing the risk of dry socket (RR 0.74, 95% CI 0.46 to 1.20; P = 0.22; 2 trials, 383 participants; low-certainty evidence).
The present review found some evidence for the association of minor adverse reactions with use of 0.12%, 0.2% chlorhexidine mouthrinses (alteration in taste, staining of teeth, stomatitis) though most studies were not designed explicitly to detect the presence of hypersensitivity reactions to mouthwash as part of the study protocol. No adverse events were reported in relation to the use of 0.2% chlorhexidine gel placed directly into a socket.
Platelet rich plasma in the prevention of dry socket
Compared to placebo, placing platelet rich plasma after extractions was not superior in reducing the risk of having a dry socket (RR 0.51, 95% CI 0.19 to 1.33; P = 0.17; 2 studies, 127 participants; very low-certainty evidence).
A further 21 intrasocket interventions to prevent dry socket were each evaluated in single studies, and there is insufficient evidence to determine their effects.
Zinc oxide eugenol versus Alvogyl in the treatment of dry socket
Two studies, with 80 participants, showed that Alvogyl (old formulation) is more effective than zinc oxide eugenol at reducing pain at day 7 (mean difference (MD) -1.40, 95% CI -1.75 to -1.04; P < 0.00001; 2 studies, 80 participants; very low-certainty evidence)
A further nine interventions for the treatment of dry socket were evaluated in single studies, providing insufficient evidence to determine their effects.