Evaluation of Occlusal Adjustment Material Removal on Monolithic Zirconia Blocks: An In Vitro Study
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 入组人数
- 120
- 主要终点
- The amount of material removal per stroke
研究概览
简要总结
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.
详细描述
Clinical occlusal adjustment requires precision within tens of micrometers; however, current literature lacks objective data regarding per-stroke material removal during chairside adjustment of monolithic zirconia. As a result, clinical decision-making largely depends on subjective judgment.
Objective
The objective of this study is to quantify material removal per single reciprocating grinding stroke on monolithic zirconia blocks using a silicon carbide grinding stone and to compare performance among operators with different levels of clinical experience.
Methods
Monolithic zirconia specimens (VITA YZ ST; dimensions: 8 × 2 × 15 mm) will be milled, sintered, and embedded into standardized holders. Operators will include 40 fourth-year dental students, 40 sixth-year dental interns, and 40 experienced clinicians. Each participant will perform 100 grinding strokes along an 8-mm linear path at a frequency of 100 strokes per minute, guided by a metronome.
研究设计
- 研究类型
- Observational
- 观察模型
- Case Control
- 时间视角
- Prospective
入排标准
- 年龄范围
- 20 Years 至 40 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Group A: Forty fourth-year dental students who have completed preclinical courses in operative dentistry, complete denture prosthodontics, and fixed prosthodontics (Part I). They have little to no experience in adjusting zirconia.
- •Group B: Forty sixth-year dental interns. Each participant will be tested twice-once before and once near the end of their clinical training. A questionnaire will also record their prosthodontic clinical experience within the past year.
- •Group C: Forty licensed clinicians with 0-5 years of post-graduation experience (with practical experience in zirconia adjustment). A questionnaire will also document their clinical experience in prosthodontics.
排除标准
- •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).
结局指标
主要结局
The amount of material removal per stroke
时间窗: about 12 months
Amount of Zirconia Material Removed per Grinding Stroke(um/stroke) * Mean thickness of material removed per stroke * Median thickness of material removed per stroke
次要结局
- Change in Material Removal Rate Between Grinding Phases(approximately 12 months)
- Percentile Distribution of Zirconia Material Removal by Operator Experience Level(approximately 12 months)