Immunological and Regenerative Implications of Corrosion of Dental Materials

Phase 2

Completed

• Conditions: Caries; Enamel; Gingivitis
• Interventions: Combination Product: Exposure to oral antiseptics or enamel remineralisation agent

• Registration Number: NCT03334461
• Lead Sponsor: University of Rijeka

Brief Summary

During orthodontic treatment intraoral corrosion results with release of nickel and titanium ions from orthodontic appliances in surrounding tissues. Those transported in the saliva and blood may cause a series of side effects from hypersensitivity reactions and soft tissue proliferation to cyto and genotoxicity. Nickel is one of the strongest contact allergens, present in numerous dental alloys. The aim of this project is to investigate the immune potential of nickel and titan ions (development of allergies, changes in cariogenic potential of dental plaque, resistance of gingivitis to therapy, and bacterial resistance to antibiotics) and changes in performance of orthodontic appliances with repercussion on regeneration of bone and periodontal tissues.

Detailed Description

Tooth movement with appliances based on nickel and titanium has got great osteogenic potential and can regenerate deficient parts of alveolar bone and gingiva and rehabilitate compromised occlusal relations and a patient's masticatory function. Due to the extended duration of this therapy, different procedures are carried out and materials are applied for prevention and regeneration of damaged enamel and oral mucosa. The oral cavity may be considered a galvanic cell in which dental alloys act as electrodes, while saliva and oral preventive and regenerative agents act as electrolites. The interaction causes corrosion, reduction of elasticity and increase of stiffness of appliances, which may in turn result in excessive forces, a disruption of tissue regeneration and irreparable damage of tooth roots, surrounding alveolar bone, periodontal ligament, gingiva and pulp.

During the extended exposion, released corrosive products in surrounding tissues and those transported in saliva and blood may cause a series of side effects from hypersensitivity reactions and soft tissue proliferation to cyto and genotoxicity. Today, allergies are ever more frequent and arise earlier in life. A specific group are children and young adolescents in pubertal growth, a period in which the immune system develops. Nickel is one of the strongest contact allergens, present in numerous dental alloys. Nickel allergy is occurs in up to 28.5% of population and cannot be deemed as low potential risk anymore.

In contrast, titan was considered a biocompatible material of no allergic potential. However, there is an increase in the frequency of presentations of different hypersensitivity reactions to titan, especially in patients with pacemakers. Numerous patients with hip endoprostheses, stents, dental implans and orthodontic appliances are exposed to titan. Titan allergy may be the cause of unexplained cases of failure and rejection of dental implants. Nickel and titan could cause bacterial resistance to antibiotics which may complicate treatment of a series of infections that are more frequent in children and adolescents.

Regulations for safety of medical products regulate safety issues of materials through mandatory laboratory testing and expertise. However, the testing of interactions of these materials with newly formed materials for prevention of damage and regeneration of orodental tissues is not obligatory prior to the start of their commercial use. Such testing should be conducted by independent scientific insitutions and not by producers with direct commercial interest.

The aim of this project is to investigate:

1. the corrosion of dental materials and appliances based on nickel and titan (in saliva and due to interaction with probiotics, remineralising agents and antiseptics)

2. the immune potential of nickel and titan ions (development of allergies, changes in cariogenic potential of dental plaque, resistency of gingivitis to therapy, and bacterial resistance to antibiotics)

3. the effect of nickel and titan ions cellular level

4. changes in performance of dental appliances with repercussion on regeneration of bone and periodontal tissues.

Study Timeline

• Study Start: 2015-12-01
• Study First Submitted: 2017-10-30
• Study First Submitted QC: 2017-11-02
• Study First Posted: 2017-11-07
• Primary Completion: 2022-03-30
• Status Verified: 2022-05
• Study Completion: 2022-05-17
• Last Update Submitted: 2022-05-20
• Last Update Posted: 2022-05-26

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 60

Inclusion Criteria

• patients with fixed orthodontic appliances
• must be able to do a mouthwash

Exclusion Criteria

• patients allergic to fluoride agents and chlorhexidine gluconate

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
oral antiseptic	Exposure to oral antiseptics or enamel remineralisation agent	first month brushing teeth without toothpaste three times per day and using oral antiseptic chlorhexidine mouthwash (Curasept ADS 212 a 200ml 0,12%) twice per day next two months brushing teeth three times per day with toothpaste containing low concentration of fluorides (1450 ppm)
high concentration enamel remineralisation agent	Exposure to oral antiseptics or enamel remineralisation agent	first month brushing teeth three times per day: twice per day with high-fluorides gel (Mirafluor K gel cola 6150 ppm F pH 5.1) and once per day without toothpaste and fluoride gel next two months brushing teeth three times per day with toothpaste containing low concentration of fluorides (1450 ppm)

Primary Outcome Measures

Name	Time	Method
Reaction of oral bacterial flora to oral antiseptics and dental remineralisation agents	30 days	Detection of change of count of Streptococcus mutans, sorbinus and salivarius and total bacterial count assesed by qPCR in the dental plaque before and after intervention in patients with fixed orthodontic appliances.

Secondary Outcome Measures

Name	Time	Method
Friction of dental alloy	90 days	Friction coefficient (no units)
Forces produced by dental alloy	90 days	Load and unload forces measured by three-point bend test (N)
Dental arch shape	90 days	Measuring anterior and posterior dental arch width (in millimeters), anterior depth and depth to width ratio in orthodontic patients wearing uncoated nickel-titanium 0.020''x0.020'' archwire on the day of putting the archwire and on the day of removing it.
Oral hygiene	210 days	Assessing accumulation of dental biofilm with Modified Silness and Loe Plaque Index (0-3; 0=no plaque and 3=continuous line of dental bacterial plaque more than 1 millimetre).
Gingivitis	210 days	Assessing extent of gingivitis by Full Mouth Bleeding Score (percentage).
Corrosion of dental alloy	90 days	Potential of corrosion, passive film breakdown and repassivation (mV)
Hardness of dental alloy	90 days	Vickers Pyramid Number (HV)
pH of dental biofilm	210 days	Measuring pH of dental biofilm (colorimetric test with pH scale range from 4 to 7).
Surface roughness of dental alloy	90 days	Surface roughness assessed by Atomic Force Microscopy (nm)
Stifness of dental alloy	90 days	Young's modulus and yield strength (GPa)
Elasticity of dental alloy	90 days	Modulus of resilience and springback ratio (MJ/m-3)

Trial Locations

Locations (1)

University of Rijeka Faculty of Dental Medicine; 🇭🇷 Rijeka, Croatia