Salivary Flow, pH, and Buffering Capacity in Fixed and Clear Aligner Orthodontic Treatment

NCT07397871 | Not Yet Recruiting

• 1 other identifier: REU-CA-SALIVA-RCT-001
• Study Type: interventional
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

Study Design: A randomized controlled trial with two parallel arms and an allocation ratio of 1:1. Setting: The study will be conducted in the orthodontic department of Riyadh Elm University hospitals in Riyadh City, Saudi Arabia. Participants: Patients undergoing fixed or clear aligner orthodontic treatment referred to REU dental hospital will be randomly allocated to either the clear aligner group or the fixed orthodontic appliance group. Intervention: Prior to orthodontic treatment, all patients will receive phase I periodontal therapy and oral hygiene instructions. Fixed orthodontic appliances will be bonded using metallic brackets with a 0.022-inch slot and 0.014-inch NiTi archwires. Clear aligner patients will receive Invisalign® treatment. Outcomes and Saliva Collection: Salivary samples will be collected using the spitting method at baseline (T0) and follow-up time points according to the study protocol. Salivary flow rate, pH, and buffering capacity will be assessed as described in the proposal. Randomization and Blinding: Randomization will be performed using a random number generator with allocation concealment via opaque envelopes. The investigators involved in outcome assessment and data analysis will be blinded. Ethical Considerations: The study will be submitted to the Institutional Review Board at Riyadh Elm University and conducted in accordance with IRB policies.

Conditions

Orthodontic Treatment; Saliva

Keywords

Salivary flow; Salivary pH; Buffering capacity; Fixed orthodontic appliance; Clear aligner therapy

Outcome Measures

Primary Outcomes (1)

• Salivary flow rate

  The salivary flow rate will be recorded in each patient. Two mL of whole unstimulated saliva will be collected in a graduated tube. The salivary flow rate will be recorded in all the four time points T0, T1, T3 and T4.

  The outcome measure will be assessed at (T0) just before the commencement of fixed appliance and Clear Aligner therapy, at one week (T1), at two weeks (T2), after three months (T3), and at six months (T4) of treatment.

Secondary Outcomes (2)

• Salivary pH

  The outcome measure will be assessed at (T0) just before the commencement of fixed appliance and Clear Aligner therapy, at one week (T1), at two weeks (T2), after three months (T3), and at six months (T4) of treatment.

• Salivary buffering capacity

  The outcome measure will be assessed at (T0) just before the commencement of fixed appliance and Clear Aligner therapy, at one week (T1), at two weeks (T2), after three months (T3), and at six months (T4) of treatment.

Study Arms (2)

Fixed orthodontic treatment control group

ACTIVE COMPARATOR

Study subjects in control group will receive fixed orthodontic appliances with metallic brackets of 0.022-inch slot size (American Orthodontics). The bonding process will be performed using the same adhesive (BracePaste, American Orthodontics) for all patients, and treatment will be initiated with 0.014-inch NiTi archwires (Highland Metals).

Device: Fixed orthodontic appliances

Clear Aligner Treatment Group

EXPERIMENTAL

Study subjects in Clear Aligner treatment group will receive Invisalign® (Align Technology, Inc., Tempe, AZ, USA). The Clear Aligner treatment protocol will be followed until the end of the treatment.

Device: Clear Aligner Treatment

Interventions

Fixed orthodontic appliances DEVICE

Study subjects in control group will receive fixed orthodontic appliances with metallic brackets of 0.022-inch slot size (American Orthodontics).

Fixed orthodontic treatment control group

Clear Aligner Treatment DEVICE

Study subjects in Clear Aligner treatment group will receive Invisalign® (Align Technology, Inc., Tempe, AZ, USA). The Clear Aligner treatment protocol will be followed until the end of the treatment.

Clear Aligner Treatment Group

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Class I, II and III skeletal malocclusion.
• Age ≥18 undergoing fixed or Clear aligner orthodontic treatment.

You may not qualify if:

• Current medications including antibiotic use within the past 3 months that affect salivary flow and composition.
• Active smoking including vaping and E-cigarette use.
• Diagnosis of systemic diseases/conditions such as Sjogren's syndrome, diabetes, chronic kidney diseases, neurological conditions.
• Active dental caries or signs of gingivitis and/or periodontitis
• Less than three months of orthodontic treatment since it is characterized by acute, temporary changes and patient adaptation to the new appliances.
• Requiring single arch treatment to standardize the research and eliminate a potential confounding variable
• Crown restoration is excluded due to their material properties which may affect salivary composition.
• Pregnancy due to the physiological variation in salivary flow and composition due to hormonal changes.
• Presence of mouth breathing may lead to inconsistent salivary flow rate, Changes in Salivary Composition and pH
• Poor oral hygiene with high levels of dental plaque, calculus, and gingival inflammation can independently alter salivary flow rate, pH, and buffer capacity there by acting as confounding variable.

Sponsors & Collaborators

• Riyadh Elm University: lead

Study Sites (1)

Riyadh Elm University

Riyadh, Saudi Arabia

Location

Related Publications (3)

• Arab S, Nouhzadeh Malekshah S, Abouei Mehrizi E, Ebrahimi Khanghah A, Naseh R, Imani MM. Effect of Fixed Orthodontic Treatment on Salivary Flow, pH and Microbial Count. J Dent (Tehran). 2016 Jan;13(1):18-22.

  PMID: 27536324 BACKGROUND

• Leone CW, Oppenheim FG. Physical and chemical aspects of saliva as indicators of risk for dental caries in humans. J Dent Educ. 2001 Oct;65(10):1054-62.

  PMID: 11699977 BACKGROUND

• Alshahrani I, Hameed MS, Syed S, Amanullah M, Togoo RA, Kaleem S. Changes in essential salivary parameters in patients undergoing fixed orthodontic treatment: A longitudinal study. Niger J Clin Pract. 2019 May;22(5):707-712. doi: 10.4103/njcp.njcp_606_18.

  PMID: 31089027 BACKGROUND

Related Links

• Arab S, Nouhzadeh Malekshah S, Abouei Mehrizi E, et al. (2016) Effect of Fixed Orthodontic Treatment on Salivary Flow, pH and Microbial Count. Journal of Dentistry (Tehran, Iran) 13(1): 18-22. Razan'S Alsalamah Proposal 3-To…
• Dawes C (2003) What is the critical pH and why does a tooth dissolve in acid? Journal (Canadian Dental Association) 69(11): 722-724.
• Leone CW and Oppenheim FG (2001) Physical and chemical aspects of saliva as indicators of risk for dental caries in humans. Journal of Dental Education 65(10): 1054-1062.

MeSH Terms

Interventions

Orthodontic Appliances, Fixed

Intervention Hierarchy (Ancestors)

Orthodontic Appliances; Orthodontics; Dentistry

Central Study Contacts

Razan Musaad Alsalamah

CONTACT

00966553771240; razan.alsalamah2024@student.riyadh.edu.sa

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: The outcome assessor, and data analyst will be blinded.
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor, Preventive Dentistry Department College of Medicine and Dentistry, Riyadh Elm University

Model Details: A non-inferiority randomized controlled trial with two parallel arms and an allocation ratio of 1:1.

Study Record Dates

• First Submitted: February 2, 2026
• First Posted: February 9, 2026
• Study Start: March 15, 2026
• Primary Completion (Estimated): February 15, 2027
• Study Completion (Estimated): May 29, 2027
• Last Updated: February 9, 2026

Record last verified: 2026-02

Locations

SA (1)