Wear Characteristics of Denture Teeth

Study Overview
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Brief Summary
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The majority of teeth utilized in the fabrication of conventional complete dentures are made of acrylic resins. These acrylic teeth provide increased bond strength to the denture base and are much easier to adjust for correct denture occlusion compared to teeth made of harder materials, such as porcelain. However, the acrylic teeth will wear faster than the porcelain teeth, leading to alterations in how the teeth contact each other if the denture is not replaced periodically (typically every 5-8 years). With the increase in biting and chewing forces that can be achieved during function with dentures supported by dental implants, the rate of tooth wear may be increased, leading to more frequent need for replacement of the prosthesis. Acrylic teeth made of nano hybrid composite material (NHC) potentially offer greater wear resistance and aesthetic characteristics. The NHC teeth employ a wide range of fillers, including highly cross-linked organic macrofillers, high-density inorganic microfillers and silanized silica based nanofillers. The macrofillers are, to a large part, responsible for the adequate strength and color-stability of the teeth, whereas the microfillers improve the wear resistance. The nanofillers offer fundamentally different optical behaviour from those of larger fillers, improving light reflection without lowering the translucency. This offers additional opportunities in the development of composite teeth, which have to exhibit lifelike aesthetics and translucency. These teeth made of nano-particles and hybrid composites can be made with two different techniques, one where the materials are pressed together and another using an injection technique. The injection method has been found to have better aesthetic results, but resistance to wear in clinical use has not been established. The purpose of this study is to evaluate the wear characteristics of new resin denture teeth (nano particles - hybrid composite) made by an injection technique. Twenty-four edentulous subjects will be enrolled who have completed implant placement for mandibular implant overdentures opposing a maxillary complete denture or implant overdenture, or patients that have previously received these dentures and are interested in having new dentures. Both maxillary and mandibular dentures will be fabricated using injection molded nano-hybrid composite denture teeth. The wear of denture teeth will be evaluated using stereophotographic recordings at baseline, 6, 12, 18 and 24 months after denture treatment.

Official Title
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Evaluation of Wear Characteristics of Nano-Hybrid Denture Teeth

Conditions
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Dentures

Intervention / Treatment
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* Device: Denture teeth


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Being treated at UCLA School of Dentistry clinics with implant-assisted mandibular overdentures and conventional maxillary complete dentures or implant overdentures Previously treated at UCLA School of Dentistry clinics with implant-assisted mandibular overdentures and conventional maxillary complete dentures or implant overdentures and desires new dentures Have healthy, normal soft and hard oral tissues Exclusion Criteria: Oral and medical conditions which would interfere with follow-up evaluations over a two-year period after denture treatment completion Abnormal oral soft or hard tissues that prevents conventional denture fabrication Impaired dexterity the prevents proper oral hygiene Allergy to denture base materials Severe parafunction based on current condition of existing dentures Any limitation in mouth opening or closing Severe TMD symptoms Employees (and their immediate families) of the UCLA School of Dentistry

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Nano Hybrid Composite Denture teeth<br>Denture teeth are made of nano hybrid composite material | Device: Denture teeth<br>* Denture teeth made of nano hybrid composite material<br>* Other names: Ivoclar Vivadent Inc. SR Phonares denture teeth;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Location of Posterior Denture Tooth Wear | Clinical evaluation of posterior wear location (right, left, equal). | 6 months after denture completion | 
| Location of Posterior Denture Tooth Wear | Clinical evaluation of posterior wear location (right, left, equal) | 12 months after denture completion | 
| Location of Posterior Denture Tooth Wear | Clinical evaluation of posterior wear location (right, left, equal) | 18 months after denture completion | 
| Location of Posterior Denture Tooth Wear | Clinical evaluation of posterior wear location (right, left, equal) | 24 months after denture completion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Denture Teeth Esthetics | Clinical evaluation of color deviation of anterior teeth to shade guide (3 levels: high, little, none) | 6 months after denture completion | 
| Amount of Denture Teeth Plaque | Clinical evaluation of plaque for anterior teeth and left posterior teeth and right posterior teeth on four-point scale (0= none; 1 = soft debris covering ≤1/3 of tooth surface; 2 = soft debris covering > 1/3 and ≤ ½ of tooth surface; 3 = soft debris covering more than ½ of tooth surface) | 6 months after denture completion | 
| Denture Teeth Calculus | Clinical evaluation of calculus for anterior teeth and posterior teeth on left and right sides on four-point scale (0= none; 1 = present on ≤ 1/3 of gingival margins; 2 = present on > 1/3 of gingival margins and parts of fissures and/or individual spots around cervical portion of tooth; 3 = covering more than ½ of gingival margins and the complete fissures and/or continuous heavy band of calculus around cervical portion of the tooth) | 6 months after denture completion | 
| Denture Teeth Esthetics | Clinical evaluation of color deviation of anterior teeth to shade guide (3 levels, high, little none) | 12 months after denture completion | 
| Denture Teeth Esthetics | Clinical evaluation of color deviation of anterior teeth to shade guide (3 levels: high, little, none) | 18 months after denture completion | 
| Denture Teeth Esthetics | Clinical evaluation of color deviation of anterior teeth to shade guide (3 levels: high, little, none) | 24 months after denture completion | 
| Amount of Denture Teeth Plaque | Clinical evaluation of plaque for anterior teeth and left posterior teeth and right posterior teeth on four-point scale (0= none; 1 = soft debris covering ≤1/3 of tooth surface; 2 = soft debris covering > 1/3 and ≤ ½ of tooth surface; 3 = soft debris covering more than ½ of tooth surface) | 12 months after denture completion | 
| Amount of Denture Teeth Plaque | Clinical evaluation of plaque for anterior teeth and left posterior teeth and right posterior teeth on four-point scale (0= none; 1 = soft debris covering ≤1/3 of tooth surface; 2 = soft debris covering > 1/3 and ≤ ½ of tooth surface; 3 = soft debris covering more than ½ of tooth surface) | 18 months after denture completion | 
| Amount of Denture Teeth Plaque | Clinical evaluation of plaque for anterior teeth and left posterior teeth and right posterior teeth on four-point scale (0= none; 1 = soft debris covering ≤1/3 of tooth surface; 2 = soft debris covering > 1/3 and ≤ ½ of tooth surface; 3 = soft debris covering more than ½ of tooth surface) | 24 months after denture completion | 
| Denture Teeth Calculus | Clinical evaluation of calculus for anterior teeth and posterior teeth on left and right sides on four-point scale (0= none; 1 = present on ≤ 1/3 of gingival margins; 2 = present on > 1/3 of gingival margins and parts of fissures and/or individual spots around cervical portion of tooth; 3 = covering more than ½ of gingival margins and the complete fissures and/or continuous heavy band of calculus around cervical portion of the tooth) | 12 months after denture completion | 
| Denture Teeth Calculus | Clinical evaluation of calculus for anterior teeth and posterior teeth on left and right sides on four-point scale (0= none; 1 = present on ≤ 1/3 of gingival margins; 2 = present on > 1/3 of gingival margins and parts of fissures and/or individual spots around cervical portion of tooth; 3 = covering more than ½ of gingival margins and the complete fissures and/or continuous heavy band of calculus around cervical portion of the tooth) | 18 months after denture completion | 
| Denture Teeth Calculus | Clinical evaluation of calculus for anterior teeth and posterior teeth on left and right sides on four-point scale (0= none; 1 = present on ≤ 1/3 of gingival margins; 2 = present on > 1/3 of gingival margins and parts of fissures and/or individual spots around cervical portion of tooth; 3 = covering more than ½ of gingival margins and the complete fissures and/or continuous heavy band of calculus around cervical portion of the tooth) | 24 months after denture completion |