Effect of single dose preoperative intramuscular dexamethasone injection on lower impacted third molar surgery


This study aimed to investigate the effects of dexamethasone intramuscular injection 1 h preoperatively, in reducing facial swelling, pain and trismus after lower impacted third molar (LITM) surgery. Twenty healthy Thai patients with both LITM surgical extraction were enrolled in the study. The washout period was 1 month after the first operation. Clinical assessment of the facial swelling, pain and trismus were measured before and after operation for 7 days and the patient’s total analgesic consumption was recorded. The level of significance used in the statistical decisions was P < 0.05. Preoperative intramuscular injection of single-dose 8 mg dexamethasone reduced postoperative swelling after LITM surgical extraction significantly on the second postoperative day, but immediately after surgery and on day 7 after the surgical extraction, no significant difference was found between the dexamethasone and control groups. Dexamethasone also reduced postoperative pain after LITM surgical extraction significantly on postoperative days 2 and 7. Additionally, the amount of paracetamol decreased significantly. There were no significant differences in trismus in the study and control groups 7 days after LITM operation. Single-dose intramuscular injection of dexamethasone can reduce postoperative facial swelling and pain, without affecting trismus after LITM surgical extraction.

Lower impacted third molar (LITM) surgical extraction usually causes complications such as dysaesthesia, severe infection, bone fracture and dry socket . It may also cause facial swelling and severe pain that may seem important to patients. Previous studies have reported that dexamethasone, a well-known corticosteroid, attenuated the inflammatory mediators released from injury tissue and white blood cells .

S kjelbred and L Økken studied the effect of a single intramuscular preoperative injection of 9 mg betamethasone on postoperative pain and swelling in bilateral LITM surgical extraction. Others have used corticosteroids peri-operatively. In 2000, A lexander et al. reviewed the literature on the use of cortisone, hydrocortisone, methylprednisolone, dexamethasone and betamethasone in dental surgery, reducing the release of cortisol, migration inhibiting factor, β-endorphins and inflammatory tissue mediators (lymphokines, prostaglandins, serotonin and bradykinin) from injured tissue. Facial swelling was decreased; the decrease in β-endorphins increased the level of pain.

G raziani et al. studied postoperative pain and facial swelling, using 10 mg submucosal dexamethasone, 4 mg and 10 mg endo-alveolar powder, all given peri-operatively. G rossi et al. studied the effect of submucosal administration of dexamethasone on discomfort after mandibular third molar surgery. Studies on dexamethasone consumption noted a decrease in trismus and facial swelling.

F ilho et al. studied the effects of preoperative dexamethasone (4 and 8 mg) consumption, to decrease pain, facial swelling and trismus. Dexamethasone of 8 mg was more effective than that of 4 mg at reducing facial swelling and trismus.

Many types, dosages and times of administration have been studied for dexamethasone, but no study of 1 h single-dose preoperative intramuscular injection of dexamethasone has been undertaken. Dexamethasone can reduce inflammation, especially following intramuscular injection. This study aimed to investigate the effects of intramuscular injection of 8 mg dexamethasone, given 1 h preoperatively, in reducing facial swelling, pain and trismus (mouth opening limitation) after LITM surgery.

Materials and methods

20 consecutive Thai patients (6 males and 14 females) were studied. They were 19–35 years (average 21 years) of age with no underlying disease and no history of any drug allergy with bilateral LITM in similar positions ( Table 1 ), in whom LITM surgical extraction with bone removal and tooth division was indicated. Patients were randomized for the first operation, the study and control groups used double-blinded randomized sampling. Eight milligrams of (2 ml) dexamethasone was injected intramuscularly into the deltoid muscle 1 h before the operation. Two millilitres of normal saline was used in the control group. The washout period was 1 month after the first operation, and the surgical extractions were undertaken by the same surgeon.

Table 1
Type of bilateral LITM in similar positions in this study.
Type of LTM Number
Horizontal LITM 10
Distoangular LITM 1
Mesioangular LITM 7
Difficult vertical LITM 2

This study was approved and accepted as a clinical study protocol by the Mahidol University Institutional Review Board with Protocol No. MU-IRB 2010/281.0810. All examinations and treatment were performed with the signed consent of the patients in the presence of a witness. Written consent was also obtained from the patients to present the study findings.

The LITM patients were given 1 g amoxicillin 1 h before surgery. The length of their faces was measured using the reference points: inferior border of earlobe to corner of the mouth; inferior border of earlobe to soft tissue pogonion; and lateral corner of the eye to angle of the mandible ( Fig. 1 ). Pain levels were measured using a visual analogue scale and the maximum interincisal distance was also evaluated.

Fig. 1
Reference lines for facial length measurement.

Surgery was performed under local anaesthesia using the same technique: triangular flap elevation, some buccal bone removal with tooth division and wound closure by interrupted suture . The postoperative medication for both groups was 500 mg amoxicillin four times a day for 5 days, and 1 g paracetamol every 4–6 h as needed, but did not exceed 4 g per day. The patients recorded their analgesic (paracetamol) consumption each day for 7 days postoperatively.

Immediately after the surgery and on postoperative days 2 and 7, facial swelling (measured by increase in the length of the face), pain levels and the interincisal distance were measured. The data were analysed statistically, using Statistical Package for the Social Sciences (SPSS), by means of analytical statistics and the Wilcoxon signed ranks test, with the level of significance set at P < 0.05.


This study showed no postoperative infection and no complications from intramuscular injection of 8 mg dexamethasone. No significant difference was found for surgical times between the groups. Dexamethasone significantly reduced postoperative facial swelling after LITM surgical extraction. The difference was not significant immediately after LITM surgical extraction but on postoperative day 2 a significant difference was found between the dexamethasone and control groups in facial swelling; no significant difference was observed on postoperative day 7 ( Table 2 ).

Table 2
Facial swelling (increase in face length after surgery) immediately and on days 2 and 7 after LITM operation.
Time of facial swelling measurements (mm) Dexamethasone group Normal saline solution group p -Value
Mean Std. deviation Mean Std. deviation
Immediately postoperation 4.8 3.02 6.4 5.58 0.48
Day 2 postoperation 8.0 5.49 16.35 15.37 0.02
Day 7 postoperation 2.8 3.5 7 9 0.09
Significance level: p < 0.05.

This study showed no significant difference between the groups in pain, measured by visual analogue scale, immediately after LITM surgical extraction, but dexamethasone was significantly effective in reducing pain on postoperative days 2 and 7 ( Table 3 ). Pain was also evaluated from the total paracetamol consumption. Fewer analgesics were consumed by those who received dexamethasone rather than saline ( Table 4 ).

Jan 26, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Effect of single dose preoperative intramuscular dexamethasone injection on lower impacted third molar surgery
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