Root canal therapy will ideally eliminate post-endodontic pain but occasionally analgesics are needed to diminish the pain [Owatz et al 2007]. Development of pain after completion of root canal treatment may undermine patients' confidence in the procedure and the clinician [Albashaireh and Alnegrish 1998]. Non-steroidal anti-inflammatory drugs are one of the most frequently taken analgesic medications for dental pain. Their popularity attributed to their efficacy in relieving pain and fever and low side effect profile at therapeutic doses [Attar et al 2008]. Mono-therapy analgesic has a low effect on dental pain. Improvement was performance by combining analgesics with different mechanisms of action without raising any adverse effects [Mehlisch 2002], was effective in controlling moderate to severe pain. The combination of a non-steroidal anti-inflammatory drug (NSAID) and paracetamol has shown additive analgesia for treating dental pain in several studies [Breivik et al1999, Keiser and Hargreaves 2002]. Endodontic treatment with a lower prevalence of postoperative pain is usually the treatment of choice.There have been no controlled dental studies evaluating the additive effects of combining a non-steroidal anti-inflammatory drug with paracetamol. Breivik et al1999 & Menhinick et al 2004 found that a combination of acetaminophen and ibuprofen was more effective than ibuprofen alone in managing postoperative pain [Breivik et al1999 & Menhinick et al 2004]. Aim of the present study, to evaluate the efficacy of the paracetamol when used alone and in combinations with three groups of drugs to control postoperative endodontic pain.

Background: Management of pain is challenging part of dental treatment; sometimes pain is a major postoperative symptom after many dental procedures especially for endodontics. The aim of the present randomized clinical trial was to investigate the efficacy of using paracetamol alone and three combinations of non-steroidal anti-inflammatory drugs with paracetamol, to control postoperative endodontic pain.

Methodology: 185 patients who had anterior or premolar teeth with irreversible pulpitis without any signs and symptoms of apical periodontitis and with moderate to severe pain. Patients were divided by allocation randomization into five groups. Four experimental groups receiving different medication; group I (single dose of paracetamol); group II (ibuprofen / paracetamol); group III (mefenamic acid /paracetamol), group IV (diclofenac k / paracetamol) and group V (no medication group). The groups received the medication after the first appointment where the pulp removed, and canals fully prepared. Pain intensity was scored by using both verbal rating scale (VRS-4) and numerical rating scale (NRS-11). The pain scores were recorded before the initial endodontic therapy for up to 8 hours postoperatively. Sign test used for comparing pain score before and after treatment. This randomized control clinical trial was conducted on patients who were considered potential candidates if they had moderate to severe spontaneous pain of odontogenic origin (ranging from 4-10 score based on the numerical rating scale (NRS-11)). Patients were selected from those attending the Conservative dentistry clinics in both the University and the Teaching Hospital Emergency Clinic.

The medications were prepared in the laboratories of faculty of Pharmacy. Four groups of medications were prepared and a placebo as follows; Group I: paracetamol 1000mg Group II: ibuprofen 600mg + paracetamol 1000mg, Group III: Mefenamic acid 500mg + Paracetamol 1000mg Group IV: Diclofenac K 50mg + paracetamol 1000 mg Group V: Placebo

Inclusion Criteria:

1. Spontaneous pain moderate to severe on the verbal rating scale (VRS-4), ranging from 4-10 score based on the numerical rating scale (NRS-11).
2. Adult patients presented for emergency endodontic treatment with a symptomatic maxillary or mandibular tooth (anterior and premolar) with a pulpal diagnosis of Irreversible pulpitis and normal periapex.
3. Patient choose to have root canal treatment for pain of endodontic origin.
4. The patient presented with American Society of Anesthesiologists (ASA) I or II medical history (ASA 1963).
5. The patient had read and thoroughly understood the pain score level sheet

Exclusion Criteria:

1. Patients below 18 years of age;
2. Analgesic taken within the last 4 hours;
3. History of allergy to NSAIDs, paracetamol or local anaesthetics;
4. History of uncontrolled systemic disease [gastrointestinal (GI) disorders, oesophageal reflux, active asthma, decreased hepatic function, haemorrhagic disorders, or poorly controlled diabetes mellitus].
5. Patients currently taking opioids, monoamine oxidase inhibitors, tricyclic antidepressants, carbamazepine, diuretics, or anticoagulants;
6. There was history of opioid addiction or abuse; and
7. Pregnant or nursing female patients.

Not shared

Patients reporting symptoms of irreversible pulpitis were requested to participate in the study, before intervention

2 years

August 2012-August 2014

One limitation was the time frame for the analysis of pain; more information would have been available if there were a 24-hour outcome line