The Effect of Two and Four Activations Per Day of the Periodontal Distractor on Pain Intensity and Pulp Vitality of Maxillary Canine: Randomized Clinical Trial
Phase: NA
Conditions: Distraction of Bone
Sponsor: Al-Azhar University

Cover paper 
 
Research title: (The effect of two and four 
activations daily of the periodontal distractor on pain 
intensity and pulp vitality of maxillary canine: 
Randomized Clinical Trial) 
   
Study Start: February 1, 2021   [Actual] 
Primary Completion: August 1, 2022   [Actual] 
Study Completion: October 15, 2022   [Actual] 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
 
 
Objectives:  
Since the periodontal distractor may cause some degree of suffering for the 
patients and may affect pulp vitality, Therefore the aim of the present study was to 
evaluate the effect of twice and four activations day of periodontal distractor on pain 
intensity and pulp vitality of maxillary canine. 
 
Methodology: 
PICO: 
 Problem: orthodontic patients that have  
              (1)Class I malocclusion severe crowding or bi maxillary protrusion 
              (2)Class II div 1 malocclusion. 
 Intervention: performing bilateral maxillary 1st premolar extraction, 
inter septal bone cuts then placing periodontal distractor and activate it 
till complete canine retraction. 
 Comparison: two versus four activation per day. 
 Outcomes:   
   Pain intensity. 
                           Pulp vitality.       
 
Study design 
The study was randomized control study. It was conducted in a sample of 32 
canines on 16 female patients attending the Faculty of Dental Medicine for Girls, Al 
Azhar University, seeking for orthodontic treatment. Their age was ranged from 16 to 
22 years. This prospective study was approved by Research Ethic Committee (REC), 
Faculty of Dental Medicine for Girls, Al Azhar University with this code (REC-OR-
21-01) Fig. (8) Showing CONSROT 2010 flow diagram of this study.  
All study participants have signed on written informed consent prior to 
enrollment. The steps of the study, the aim, the potential benefits, and hazards, all 
were discussed with the patients.  
Sample size calculation: 

To Compare the effects of two different orthodontic treatment modalities on 
pain; independent t test was used for comparison between groups. According to a 
previous study by Raza et al (2021), Mean VAS scores were 16 ± 3.94 (24 hours) at 
control side, in comparison to 46.50 ± 6.69 (24 hours) A minimum total sample size 
of 6 samples on each group are sufficient to detect the effect, by increasing 2 patients 
on each group to overcome dropping out of patients, the number were 8 on each group 
and 16 on both groups (fig 1). 
 
 
Patient Records  
Inclusion criteria were: 1-Orthodontic Patients need extraction of first 
permanent premolar for orthodontic reasons (dentoalveolar maxillary protrusion, 
Class II div 1 malocclusion), 2-No history of previous orthodontic treatment, 3- 
Absence of any systemic disease, 4- Good oral hygiene and healthy gums look, with 
no signs of redness, edema, or bleeding during brushing (periodontal inflammation), 
5- Highly motivation and cooperation  
Exclusion criteria were: 1- Medically compromised patients, -2-Use of 
medication that may affect tooth movement during the period of the study. 
After patient selection, routine records of all the patients such as a detailed 
case history, pretreatment study model, extraoral and intraoral photographs, panorama 
and lateral cephalometric radiographs were acquired. Pain intensity and discomfort 
was evaluated at different times by Visual Analogue scale (1st 48 hour after 
intervention, during each activation of the distractor, and on the Interval between 
activation) as research related records. Electric pulp testing of canine was done before 
and after retraction to evaluate pulp vitality. 
All the patients in the study required bilateral first premolar extraction. They 
were divided into two groups (Group I): Canine retraction was done by periodontal 
distractor with twice activations per day. (Group II): Canine retraction was done by 
periodontal distractor with four activations per day. 
 Randomization Allocation concealment: 
Randomization was accomplished using online research randomizer. Numbers 
were from 1 to 16 and each group contained 8 numbers. Set 1 of numbers was 
assigned to periodontal distractor with two activations per day. Set 2 of numbers was 
assigned to periodontal distractor with four activations per day. The randomized 
numbers for the participant were written in opaque white papers which were folded, 
codes for randomization were kept with another investigator. Allocation of each 
patient to either group was done by picking up by a colleague with allocation ratio 
1:1.  
Study phases: This study included four phases: 
Phase I: Posterior segment leveling and alignment: 
For patients of both groups the orthodontic treatment was started with direct 
bonding of Roth brackets (Dynaflex,USA) to the maxillary canine, second premolars 
first molar only. Sectional nickel titanium (NiTi) arch wires were used starting from 

0.014'' up to stainless steel arch wire 0.016"×0.022". This was undertaken to align the 
posterior segment before premolar extraction to allow proper placement of distractor 
without canting. Fig. (1). 
 
Figure (1) After leveling and alignment of posterior segment with sectional 
wire. 
 
Phase II : Extraction and inter septal bone corticotomy phase. 
Patients were referred to the clinic of Oral and Maxillofacial Department, 
Faculty of Dental Medicine for Girls, Al Azhar University to extract first maxillary 
premolars with written referral note. The post extraction instructions were firm and 
clear not to use NSAIDs drugs for analgesia, paracetamol drugs were prescribed1.  
The second step consisted of performing corticotomies (grooves) in the 
interseptal bone distal to the canine with bur. Initially, two vertical grooves were done 
inside the extraction socket, along the buccal and lingual sides then, another groove 
that was extended obliquely toward the base of the interseptal bone to weaken its 
resistance Fig. (2). The depth of the undermining grooves was dependent on the 
thickness of the interseptal bone, as revealed on the Periapical films that was done 
immediately after extraction . Corticotomy was done by surgical bur on straight hand 
piece (Apple dental, china) using normal saline for irrigation to prevent adverse 
thermal changes in the periodontium. 
 
 
Fig. (2) Inter septal bone Coricotomy with surgical bur on straight hand piece 
Phase III: Periodontal distractor construction and placement: 
 A Hyrax screw(Dentauram, Germany) was modified to form a distractor. 
Bands on molar and canine were placed with a lingual button welded for the 
attachment of the elastomeric chain, to counteract any rotation force that was 
encountered by the canine during the distraction process. 

The screw was opened slightly more than the width of premolar to be extracted and 
extended arms were bent to desirable shape to be soldered on molar and canine bands. 
The distractor was placed and cemented by glass ionmer cement Fig. (3). 
               
 
Fig. (3)  Steps of periodontal distractor appliance construction from hyrax 
screw. 
Phase IV: Activation of periodontal Distraction Fig. (4) : 
Group I : The canine was distracted two per day for a total about 0.4 mm per 
day. 
Group II: four activations of 0.2 mm each for a total about 0.8 mm per day. 
 The distractor was activated till the distal surface of canine became in contact 
with the mesial surface of second premolar Fig. (5). 
The patients were instructed to apply orthodontic wax on the superior edges of 
distractor immediately after its placement to minimize discomfort of the oral mucosa 
as a result of trauma and friction between mucosal tissue and the distractor. 
 
 
Fig. (4) Activation of periodontal distractor with key 
     
     
 
Fig. (5) Before and after complete canine retraction by periodontal distractor 
 
Measurement of pain: Pain intensity and discomfort was evaluated at 
different times by Visual Analogue scale (1st 48 hour after intervention, during each 
activation of the distractor, and on the Interval between activation) Fig. (6) . 

 
Fig. (6)Visual Analogue scale of pain. 
Measurements of Pulp vitality:  
The distracted canine's pulp was recorded with noninvasive, simple and 
clinically popular device. It was electric pulp tester.   
The tip of the probe of EPT (Denjoy, china)was applied on sound enamel 
on the midpoint of each tooth. This area is the most effective site for EPT 
because of its close proximity to the highly innervated area of canine crown 
and because it provides a readily reproducible position. An interface medium 
as tooth paste was placed on tooth after its dryness with air spray to conduct 
electrical impulses to the tooth. The device has a numeric scale, and these 
numbers have been used to register changes in test responses Fig. (7).  
         
 
Fig.7 : Measurement of pulp vitality with electric pulp tester. 

 
 
Fig. (8) CONSROT 2010 flow diagram of patients’ recruitment and follow-up 
Statistical analysis:  
Comparison between different intervals was performed by using Friedman`s test 
(non-parametric data). Comparison between both groups was performed by using 
Mann Whitney`s test (non-parametric).