The Effect of Warm Saline Irrigation on the Amount of Bleeding in Impacted Mandibular Third Molar Surgery: a Split-mouth Single-blinded Randomized Controlled Clinical Trial
Phase: NA
Conditions: Surgical Blood Loss, Third Molar
Sponsor: Tehran University of Medical Sciences

 Official title: The effect of warm saline irrigation on the amount of bleeding in 
impacted mandibular third molar surgery: a split-mouth double-blinded randomized 
clinical trial 
 NCT number: NCT04143373 
 Document date: November 1, 2019 
Study Protocol and Statistical Analysis Plan 
To meet the objectives of this split-mouth double-blinded randomized controlled clinical trial, 20 
patients who were candidates for bilateral surgical extractions of mandibular third molars were 
chosen. The participants were selected based on their attendance in the Department of Oral and 
Maxillofacial Surgery of Tehran University of Medical Sciences, Tehran, Iran from October to 
December 2017. The sample size was defined to obtain test powers greater than 95% (𝛼 = 0.05, β < 
0.05). 
Patients were enrolled in this study voluntarily, and the details on the study design were explained 
to them prior to signing the informed consent agreement. The study design was approved by the 
Institutional Review Board of Tehran University of Medical Sciences, according to the principles of 
the Helsinki declaration (thesis #6234) and was registered in https://clinicaltrials.gov (Code: 
NCT04143373). 
The Inclusion and Exclusion criteria were defined as follows: 
Inclusion criteria 
 
Being a candidate for bilateral mandibular third molar surgery 
 
Both mandibular third molars must have a similar inclination to the second molar 
 
Both mandibular third molars must have same Pell & Gregory's classification, indicating the 
similar surgical difficulty on both sides. 
Exclusion criteria 
 
Presence of any systemic condition or using any type of medication 

 
History of allergy to local anesthetic (LA) solutions 
 
Patients with an active gag reflex, because they are more susceptible to swallow the 
irrigation solution. 
 
Pregnant and post-menopause women 
 
Patients with pericoronitis or any local inflammation 
Since it is easier and less time-consuming for the right-handed surgeon to extract the impacted 
molar on the right side, all surgeries were performed by one right-handed oral and maxillofacial 
surgeon. For each patient, the control and the experimental sides were chosen by a table of random 
numbers. The surgeon was aware of the experimental side, however the outcome assessor who 
checked the amount of suctioned solution, and the data analyst were blind. In the control side and 
the experimental side, 25±2°C and 37±1°C saline were used for irrigation, respectively. All other 
variables such as the flap type, number, and type of LA cartridges and suturing method were 
matched between both sides in each patient. 
The total time needed for surgery was measured from the moment of the LA injection until the end 
of suturing. For each patient only 2 cartridges of lidocaine 2% along with 1:100000 epinephrine were 
used to block the inferior alveolar (direct technique), lingual and long buccal nerves. The timespan 
between LA injection and the start of surgery was relatively the same. In case the surgery on one 
side took a relatively longer time, that case would have been excluded. 
The amount of saline for irrigation was precisely measured and patients were asked to prevent 
swallowing till the end of surgery so that all the solutions and debris were suctioned from the oral 
cavity. In case the volume of irrigation solution was different between control and experimental 
sides, compensative amount of saline was poured into the mouth and suctioned to balance the 
amount of suctioned solutions. Also, it was presumed that in healthy patients who were not on any 
medications, salivary secretion rates were almost the same between surgeries, so that the 
difference between the volumes of suctioned solutions were due to the differences in bleeding.  
The SPSS (Version 23.0, IBM Corp., 2015, New York, USA) and Independent sample T-test were used 
to analyze the findings.