Evaluation of Occlusal Adjustment Material Removal on Monolithic Zirconia Blocks: An In Vitro Study
Trial statusNot yet recruiting
Trial phaseNot listed
Trial typeObservational
Biological sexAll
Age20-40
SponsorNational Taiwan University Hospital
About this trial
This study aims to improve understanding of the amount of tooth-replacement material removed during a single grinding "stroke" performed in the adjustment of a zirconia crown. Zirconia is a highly durable ceramic material commonly used for dental restorations, and accurate adjustment is essential for achieving proper occlusion. However, existing literature does not provide quantitative data regarding material removal per stroke during chairside adjustment, resulting in reliance on individual clinical experience.
In this study, standardized zirconia specimens will be prepared and assigned to three operator groups: dental students, dental interns, and experienced clinicians. Each participant will perform a controlled number of grinding strokes on the specimens using a commonly used dental grinding stone. Specimens will be scanned before and after grinding using a three-dimensional scanner to precisely quantify material removal.
Hypothesis
The hypotheses of this study are:
Each grinding stroke results in a measurable and relatively consistent amount of zirconia material removal.
Experienced clinicians demonstrate more controlled and predictable material removal per stroke compared with students and interns.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
None
Disqualifiers
Acute upper-limb/hand injuries or postoperative recovery within the past 3 months that may affect grip strength or fine motor control.
Neuromuscular disorders or tremor/postural control impairments (e.g., essential tremor, peripheral neuropathy, moderate to severe carpal tunnel syndrome) that prevent stable operation.
Uncorrected or inadequately corrected vision that does not meet the requirements for close-range tasks (e.g., inability to clearly see fine markings at a distance of 30-40 cm even with correction).
Inability to follow the metronome rhythm (100 beats per minute).
Trial population
The study population consists of 120 participants from three levels of dental training and early clinical practice, recruited from a dental school and affiliated clinical institutions. The sample includes: 1. Fourth-year dental students 2. Sixth-year dental interns 3. Clinicians with 0-5 years of post-graduation experience Participants are generally healthy adults capable of performing fine motor tasks required for dental procedures. Exclusion criteria include acute hand/upper-limb injuries, neuromuscular disorders, uncorrected poor vision, and inability to follow a metronome rhythm.
Trial design
Design model
Case-control
Time perspective
Prospective
Treatments tested in this trial
perform material removal on monolithic zirconia
Procedure/SurgeryEach participant will perform 100 strokes along an 8-mm path at a rate of 100 strokes per minute, guided by a metronome on the monolithic zirconia
Treatment groups
120 Participants
are divided into 3 treatment groupsGroup A: A.fourth-year dental students1 intervention
Group B: B.sixth-year interns1 intervention
Group C: C.clinicians1 intervention
Trial outcomes
Primary outcomes
1
The amount of material removal per stroke
Amount of Zirconia Material Removed per Grinding Stroke(um/stroke) * Mean thickness of material removed per stroke * Median thickness of material removed per stroke
Time frame
about 12 monthsSecondary outcomes
1
Change in Material Removal Rate Between Grinding Phases
Difference in mean zirconia material removal per stroke between early grinding phase (strokes 1-50) and late grinding phase (strokes 51-100) Unit of Measure: μm/stroke (difference between phases)
Time frame
approximately 12 months2
Percentile Distribution of Zirconia Material Removal by Operator Experience Level
Percentile distribution (e.g., 25th, 50th, 75th percentiles) of zirconia material removal per grinding stroke within each operator experience group Unit of Measure: percentile values
Time frame
approximately 12 monthsLocations
Sponsors and contacts
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Source ClinicalTrials.gov
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