Root Canal TherapyAS-RCTNCT03053037
Apical Size and Root Canal Treatment Success Trial (AS-RCT Trial)
A study testing final apical size instrumentation in people with Root Canal Therapy, run by University of Washington at 2 sites in United States.
Trial summary
This study is looking into two different ways to perform a root canal treatment. The study will look at differences and compare the two different treatment options over a 2-year period.More specifically, this study evaluates a small "skinny" root canal shape compared to a larger "broad" root canal shape and if this… Read more about this study
- Who is it for?
- Ages 18 to 85 yearsHealthy volunteers can take part
- Conditions the study is for
- Root Canal Therapy
- What is being tested?
- final apical size instrumentation
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 35 participants
- Where
- 2 sitesUnited States
- Study dates
- 5 Aug 2016to 7 Feb 2022
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 85 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Healthy adults 18-85 years old, ASA I, II
- Mandibular molars with diagnosis of necrotic pulp and periapical lesion associated with at least the mesial root
- Lesion with Periapical Index score > 2 and largest lesion dimension <10mm
- Fully developed apices and patent root canals, good periodontal health (probing depth < 4mm)
- Confirmed restorability with crown restoration after root canal treatment or adequate existing full cuspal coverage restoration
Who cannot join
- ASA Class III or IV, immune-compromised patients, pregnant women, history of diabetes or bisphosphonate treatment
- Teeth with coronal cracks that extend below the CEJ, or with non-odontogenic periapical pathology and/or with not fully developed apices
- Molars with c-shape anatomy or middle medial canal
- Patients unable to present for a recall at one-year and/or two-year post-treatment or unwilling to participate
Trial locations and contacts
2 sites in 1 country.
United States2 sites
University of Texas Health Science Center
San Antonio, Texas, 78229
University of Washington Dental School
Seattle, Washington, 98195
About this study
Official title: Impact of Final Apical Size Preparation on Root Canal Treatment Success: A Clinical, Microbiological and Volumetric Evaluation
This study is looking into two different ways to perform a root canal treatment. The study will look at differences and compare the two different treatment options over a 2-year period.More specifically, this study evaluates a small "skinny" root canal shape compared to a larger "broad" root canal shape and if this affects the success of the root canal treatment. Both types of treatment are standard of care and aim to treat the infection inside your tooth. When a tooth is infected with bacteria, we can see a dark area on the radiograph around the roots of the infected tooth. If this dark area becomes smaller or goes away completely after root canal treatment and you do not feel any pain or other symptoms, then we know that the treatment was successful and there is no need for further treatment on this tooth. To measure the size of the dark area around the tooth (i.e. volume) before and after the treatment we will need to take two limited volume three-dimensional radiographs (cone beam computed tomography-CBCT), one prior to treatment and one at two years after the root canal treatment is completed. These radiographs are more accurate in detecting changes in lesion size than the regular periapical radiographs. We will assess the changes in lesion volume for all teeth included in the study and that will help us find differences in success between the two root canal treatment protocols, We are specifically looking for persons that have been diagnosed with a necrotic permanent mandibular molar with an evident radiographic lesion (i.e. dark area around the tooth) that can be retained in the mouth with root canal treatment and permanent restoration. This study place participants in different treatment groups after randomization. Randomization means that you are placed by chance (like flipping a coin) into a treatment group. For this study, there are two treatment groups (protocol) and they are listed below.
Protocol 1: Group S: Root canal treatment will be performed in 2-visits using hand files and rotary instruments to a final canal shape of size #25.
Protocol 2: Group L: Root canal treatment will be performed in 2-visits using hand files and rotary instruments to a final canal shape of size #35
Read the detailed description
We will perform a randomized, blinded clinical trial with clinical, microbiological and volumetric outcomes. The study population will be selected from adult patients in need of endodontic treatment on mandibular molars diagnosed with pulp necrosis and presenting with a visible radiographic lesion associated with at least the mesial root. Patients will be randomized into one of the two arms (group S: apical size#25; group L: apical size#35) and followed for 2 years post-treatment.
Treatment sequence Endodontic residents under the direct supervision of a study investigator will perform all treatments; all providers will be trained and calibrated for root canal treatment protocol and microbial sample collection. The calibration session will be repeated annually until completion of the study.
Treatment protocol First Appointment
- Pre-operative CBCT will be obtained and baseline clinical signs and symptoms will be recorded. Pain level will be recorded on a 0-10 visual analog scale (VAS).
- After ascertaining adequate local anesthesia, rubber dam isolation will be obtained and the field will be disinfected with 3% hydrogen peroxide and 2.5% sodium hypochlorite (NaOCl) solution as previously described (37).
- Access will be performed and the operative field will be again disinfected with 2.5% NaOCl followed by 5% sodium thiosulphate. A microbiological sample (S0) of the field will be obtained with paper points. S0 will be used as a negative control (i.e. sterility sample).
- The mesial canal walls will then be touched lightly with hand files to disrupt bacterial biofilms and a microbiological specimen (S1) will be obtained (described in detail below).
- Orifice will be enlarged with a Protaper Universal SX rotary file (Dentsply, Tulsa, OK) Apical patency will be determined with a size #10 hand file and working length will be obtained with the use of Root ZX apex locator (J Morita USA, Irving, CA) and verified with a PA radiograph.
- Coronal 2/3 of mesial canal WL will be instrumented with Vortex Blue rotary file 25/06 (Dentsply). First apical binding file (FABF) will be recorded at this stage to serve as a covariable in the analyses.
- Apical 1/3 instrumentation of mesial canals will be carried out according to assigned group as follows:
- Group S: Instrumentation technique to working length (WL) using the sequence 15/04 →20/04 →25/04 →25/06 Vortex Blue rotary file system (Dentsply).
- Group L: Instrumentation technique to WL using the sequence 15/04 →20/04 →25/04 →25/06 → 30/04 →35/04 Vortex Blue rotary file system (Dentsply).
- Distal(s) canal instrumentation will be standardized for both groups as follows:
- Coronal 2/3 of distal canal will be instrumented with Vortex Blue rotary file 25/06 2. Apical instrumentation to WL using the sequence 15/04 →20/04 →25/04 →25/06 → 30/04 →35/04→40/04 Vortex Blue rotary file system (Dentsply) 9. The canals will be irrigated using a 30-gauge side-vented needle with 6% NaOCl (10ml/canal) followed by 17% ethylenediaminetetraacetic acid (EDTA; 5ml/canal) followed by a final rinse of 6% NaOCl (10ml/canal) and 5% sodium thiosulfate (2ml/canal).
- A microbiological specimen (S2) will be obtained from mesial canals, and then the canals will be dried with paper points.
- Calcium hydroxide [Ca(OH)2] will be placed as an interim intracanal medicament and a temporary restoration consisted of Fuji II LC (GC Corp, Tokyo, Japan) will be placed in the access. A post-op radiograph will be made.
Second appointment (within 10-14 days)
- Clinical signs and symptoms will be recorded. Pain level will be recorded on a VAS.
- After ascertaining adequate local anesthesia, rubber dam isolation will be obtained and the field will be disinfected as described above.
- Root canal system will be accessed and a second sterility microbiological sample will be obtained (S00).
- Ca(OH)2 will be removed by irrigating with 6% NaOCl (10ml/canal) followed by 17% EDTA (5ml/canal) and a final rinse of 6% NaOCl (10ml/canal). This will be followed by irrigation with 5% sodium thiosulfate (2ml/canal).
- A microbiological specimen (S3) will be obtained from mesial canals, and then the canals will be dried with paper points.
- Final obturation will be performed with gutta-percha and AH+ sealer utilizing the continuous wave condensation technique.
- Access will be restored permanently and patient will be referred to their dentist for full coverage restoration. Adequate existing full coverage restorations will remain in place. A post-op radiograph will be made.
- Conditions
- Root Canal Therapy
- Being tested
- final apical size instrumentation
- Keywords
- apical size, root canal treatment success, micro biome analysis, pulp necrosis
- Medical subject headings
- Dental Pulp Necrosis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
final apical size instrumentationProcedure or surgery
root canal instrumentation to two different final preparation sizes
| Study group | Role | What they receive |
|---|---|---|
| Group S | Active comparator | mesial canals in Group S will be instrumented to size 25 Receives: Procedure: final apical size instrumentation |
| Group L | Active comparator | mesial canals in Group L will be instrumented to size 35 Receives: Procedure: final apical size instrumentation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Success of root canal therapy
Volumetric assessment of the periapical lesion between baseline and endpoint assessment
Measured: 2 years
Secondary outcomes (1)
Relationship between the number and taxa of bacteria remaining in the root canal at the time of obturation and treatment success between the two groups.
Culture-independent, molecular methods will be performed to quantify the total bacterial count before and after treatment in each group as well as identify the specific oral taxa in the root canal and their association to treatment success.
Measured: 2 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Feb 2017
- Study start5 Aug 2016
- Primary completion30 Jan 2022
- Study completion7 Feb 2022
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Root Canal TherapyStudies of the same condition, open and under way.
- More trials run by University of WashingtonThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- randomized clinical trial 2 arms
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 35 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Washington
- Sponsor type
- University, hospital or other
- Collaborators
- American Association of Endodontists
- Responsible party
- Principal investigator, Vanessa Chrepa DDS, MS, University of Washington
- Investigators
- Vanessa Chrepa, DDS, MS, Principal investigator, University of Washington
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03053037
- Sponsor's protocol ID
- 51641
- Acronym
- AS-RCT
- Status last verified
- Feb 2022
- First submitted
- 10 Feb 2017
- Last updated
- 24 Feb 2022
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 24 Feb 2022. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Impact of Final Apical Size Preparation on Root Canal Treatment Success: A Clinical, Microbiological and Volumetric Evaluation
- ClinicalTrials.gov ID
- NCT03053037
- Acronym / sponsor ID
- AS-RCT / 51641
- Conditions
- Root Canal Therapy
- Keywords
- apical size, root canal treatment success, micro biome analysis, pulp necrosis
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 35 participants (actual)
- Lead sponsor
- University of WashingtonUniversity, hospital or other
- Collaborators
- American Association of Endodontists
- Study start
- 5 Aug 2016 (actual)
- Primary completion
- 30 Jan 2022 (actual)
- Study completion
- 7 Feb 2022 (actual)
- First posted
- 14 Feb 2017 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study is looking into two different ways to perform a root canal treatment. The study will look at differences and compare the two different treatment options over a 2-year period.More specifically, this study evaluates a small "skinny" root canal shape compared to a larger "broad" root canal shape and if this affects the success of the root canal treatment. Both types of treatment are standard of care and aim to treat the infection inside your tooth. When a tooth is infected with bacteria, we can see a dark area on the radiograph around the roots of the infected tooth. If this dark area becomes smaller or goes away completely after root canal treatment and you do not feel any pain or other symptoms, then we know that the treatment was successful and there is no need for further treatment on this tooth. To measure the size of the dark area around the tooth (i.e. volume) before and after the treatment we will need to take two limited volume three-dimensional radiographs (cone beam computed tomography-CBCT), one prior to treatment and one at two years after the root canal treatment is completed. These radiographs are more accurate in detecting changes in lesion size than the regular periapical radiographs. We will assess the changes in lesion volume for all teeth included in the study and that will help us find differences in success between the two root canal treatment protocols, We are specifically looking for persons that have been diagnosed with a necrotic permanent mandibular molar with an evident radiographic lesion (i.e. dark area around the tooth) that can be retained in the mouth with root canal treatment and permanent restoration. This study place participants in different treatment groups after randomization. Randomization means that you are placed by chance (like flipping a coin) into a treatment group. For this study, there are two treatment groups (protocol) and they are listed below.
Protocol 1: Group S: Root canal treatment will be performed in 2-visits using hand files and rotary instruments to a final canal shape of size #25.
Protocol 2: Group L: Root canal treatment will be performed in 2-visits using hand files and rotary instruments to a final canal shape of size #35
Detailed description
We will perform a randomized, blinded clinical trial with clinical, microbiological and volumetric outcomes. The study population will be selected from adult patients in need of endodontic treatment on mandibular molars diagnosed with pulp necrosis and presenting with a visible radiographic lesion associated with at least the mesial root. Patients will be randomized into one of the two arms (group S: apical size#25; group L: apical size#35) and followed for 2 years post-treatment.
Treatment sequence Endodontic residents under the direct supervision of a study investigator will perform all treatments; all providers will be trained and calibrated for root canal treatment protocol and microbial sample collection. The calibration session will be repeated annually until completion of the study.
Treatment protocol First Appointment
- Pre-operative CBCT will be obtained and baseline clinical signs and symptoms will be recorded. Pain level will be recorded on a 0-10 visual analog scale (VAS).
- After ascertaining adequate local anesthesia, rubber dam isolation will be obtained and the field will be disinfected with 3% hydrogen peroxide and 2.5% sodium hypochlorite (NaOCl) solution as previously described (37).
- Access will be performed and the operative field will be again disinfected with 2.5% NaOCl followed by 5% sodium thiosulphate. A microbiological sample (S0) of the field will be obtained with paper points. S0 will be used as a negative control (i.e. sterility sample).
- The mesial canal walls will then be touched lightly with hand files to disrupt bacterial biofilms and a microbiological specimen (S1) will be obtained (described in detail below).
- Orifice will be enlarged with a Protaper Universal SX rotary file (Dentsply, Tulsa, OK) Apical patency will be determined with a size #10 hand file and working length will be obtained with the use of Root ZX apex locator (J Morita USA, Irving, CA) and verified with a PA radiograph.
- Coronal 2/3 of mesial canal WL will be instrumented with Vortex Blue rotary file 25/06 (Dentsply). First apical binding file (FABF) will be recorded at this stage to serve as a covariable in the analyses.
- Apical 1/3 instrumentation of mesial canals will be carried out according to assigned group as follows:
- Group S: Instrumentation technique to working length (WL) using the sequence 15/04 →20/04 →25/04 →25/06 Vortex Blue rotary file system (Dentsply).
- Group L: Instrumentation technique to WL using the sequence 15/04 →20/04 →25/04 →25/06 → 30/04 →35/04 Vortex Blue rotary file system (Dentsply).
- Distal(s) canal instrumentation will be standardized for both groups as follows:
- Coronal 2/3 of distal canal will be instrumented with Vortex Blue rotary file 25/06 2. Apical instrumentation to WL using the sequence 15/04 →20/04 →25/04 →25/06 → 30/04 →35/04→40/04 Vortex Blue rotary file system (Dentsply) 9. The canals will be irrigated using a 30-gauge side-vented needle with 6% NaOCl (10ml/canal) followed by 17% ethylenediaminetetraacetic acid (EDTA; 5ml/canal) followed by a final rinse of 6% NaOCl (10ml/canal) and 5% sodium thiosulfate (2ml/canal).
- A microbiological specimen (S2) will be obtained from mesial canals, and then the canals will be dried with paper points.
- Calcium hydroxide [Ca(OH)2] will be placed as an interim intracanal medicament and a temporary restoration consisted of Fuji II LC (GC Corp, Tokyo, Japan) will be placed in the access. A post-op radiograph will be made.
Second appointment (within 10-14 days)
- Clinical signs and symptoms will be recorded. Pain level will be recorded on a VAS.
- After ascertaining adequate local anesthesia, rubber dam isolation will be obtained and the field will be disinfected as described above.
- Root canal system will be accessed and a second sterility microbiological sample will be obtained (S00).
- Ca(OH)2 will be removed by irrigating with 6% NaOCl (10ml/canal) followed by 17% EDTA (5ml/canal) and a final rinse of 6% NaOCl (10ml/canal). This will be followed by irrigation with 5% sodium thiosulfate (2ml/canal).
- A microbiological specimen (S3) will be obtained from mesial canals, and then the canals will be dried with paper points.
- Final obturation will be performed with gutta-percha and AH+ sealer utilizing the continuous wave condensation technique.
- Access will be restored permanently and patient will be referred to their dentist for full coverage restoration. Adequate existing full coverage restorations will remain in place. A post-op radiograph will be made.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, outcomes assessor)
- Number of arms
- 2
- Model description
- randomized clinical trial 2 arms
| Arm | Type | Receives |
|---|---|---|
| Group S | Active comparator | Procedure: final apical size instrumentationmesial canals in Group S will be instrumented to size 25 |
| Group L | Active comparator | Procedure: final apical size instrumentationmesial canals in Group L will be instrumented to size 35 |
Who may qualify
- Ages
- 18 to 85 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Healthy adults 18-85 years old, ASA I, II
- Mandibular molars with diagnosis of necrotic pulp and periapical lesion associated with at least the mesial root
- Lesion with Periapical Index score > 2 and largest lesion dimension <10mm
- Fully developed apices and patent root canals, good periodontal health (probing depth < 4mm)
- Confirmed restorability with crown restoration after root canal treatment or adequate existing full cuspal coverage restoration
Key exclusion criteria (4 listed)
- ASA Class III or IV, immune-compromised patients, pregnant women, history of diabetes or bisphosphonate treatment
- Teeth with coronal cracks that extend below the CEJ, or with non-odontogenic periapical pathology and/or with not fully developed apices
- Molars with c-shape anatomy or middle medial canal
- Patients unable to present for a recall at one-year and/or two-year post-treatment or unwilling to participate
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| final apical size instrumentationroot canal instrumentation to two different final preparation sizes | Procedure or surgery | Group L, Group S |
Primary outcome
Success of root canal therapy
Time frame: 2 years
Volumetric assessment of the periapical lesion between baseline and endpoint assessment
1 secondary outcome
Relationship between the number and taxa of bacteria remaining in the root canal at the time of obturation and treatment success between the two groups.
Time frame: 2 years
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Feb 2022.
- Individual participant dataSharing planned: No
Related trials for Root Canal Therapy
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Mineral Trioxide Aggregate (MTA) vs Gutta-Percha for Non-Surgical Endodontic Retreatment in Teeth With Apical Lesions
Periapical Diseases, Root Canal Therapy
Active, not recruiting
Treatment Outcome and Patient-reported Outcomes in Patient Undergoing Non-surgical Root Canal Treatment With Different Irrigation Protocols
Root Canal Treatment, Irrigation Activation
RecruitingPhase 2
Postoperative Pain Comparison of Two Root Canal Sealers in Irreversible Pulpitis
Post Operative Pain After Root Canal Therapy
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Comparison of Endodontic Flare up in Single Visit Root Canal Treatment Versus Multiple Visit Root Canal Treatment in Patients Visiting Scd, Swat.
Postoperative Complication, Root Canal Therapy
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Vanessa Chrepa, DDS, MS principal investigator
University of Washington
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing final apical size instrumentation in people with Root Canal Therapy, run by University of Washington at 2 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 24 Feb 2022. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Success of root canal therapy (time frame: 2 years). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Feb 2022; AzTrials last refreshed its copy on 7 Nov 2026.