Data from: Statistical analysis for subjective and objective evaluations of dental drill sounds

The sound produced by a dental air turbine handpiece (dental drill) can markedly influence the sound environment in a dental clinic. Indeed, many patients report that the sound of a dental drill elicits an unpleasant feeling. Although several manufacturers have attempted to reduce the sound pressure levels produced by dental drills during idling based on ISO 14457, the sound emitted by such drills under active drilling conditions may negatively influence the dental clinic sound environment. The physical metrics related to the unpleasant impressions associated with dental drill sounds have not been determined. In the present study, psychological measurements of dental drill sounds were conducted with the aim of facilitating improvement of the sound environment at dental clinics. Specifically, we examined the impressions elicited by the sounds of 12 types of dental drills in idling and drilling conditions using a semantic differential. The analysis revealed that the impressions of dental drill sounds varied considerably between idling and drilling conditions and among the examined drills. This finding suggests that measuring the sound of a dental drill in idling conditions alone may be insufficient for evaluating the effects of the sound. We related the results of the psychological evaluations to those of measurements of the physical metrics of equivalent continuous A-weighted sound pressure levels (LAeq) and sharpness. Factor analysis indicated that impressions of the dental drill sounds consisted of two factors: “metallic and unpleasant” and “powerful”. LAeq had a strong relationship with “powerful impression”, calculated sharpness was positively related to “metallic impression”, and “unpleasant impression” was predicted by the combination of both LAeq and calculated sharpness. The present analyses indicate that, in addition to a reduction in sound pressure level, refining the frequency components of dental drill sounds is important for creating a comfortable sound environment in dental clinics.牙科涡轮手机（牙钻）运行时产生的声响，会显著影响牙科诊所内的声环境。不少患者均表示，牙钻的声响会引发不适感受。尽管已有多家厂商尝试依据ISO 14457标准，降低牙钻空转状态下的声压级，但这类牙钻在主动钻孔工况下发出的声响，仍可能对牙科诊所的声环境造成负面影响。目前学界尚未明确与牙钻声响引发的负面印象相关的物理指标。本研究针对优化牙科诊所声环境的需求，开展了牙钻声响的心理学测评。具体而言，我们采用语义差分法（semantic differential），对12款牙钻在空转与钻孔两种工况下的声响所引发的主观印象进行了测评。分析结果显示，牙钻声响给人的主观印象在空转与钻孔工况间存在显著差异，且不同受试牙钻之间的印象也各不相同。这一发现表明，仅通过空转工况下的声响测量，或不足以全面评估牙钻声响的整体影响。我们将心理学测评结果，与等效连续A计权声压级（LAeq）及尖锐度（sharpness）两项物理指标的测量结果进行了关联分析。因子分析结果表明，牙钻声响给人的主观印象可归纳为两个因子：“金属感与不适感”以及“力量感”。LAeq与“力量感”存在较强关联，计算得到的尖锐度与“金属感”呈正相关，而“不适感”则可通过LAeq与尖锐度的组合进行预测。本研究的分析结果显示，若要打造牙科诊所内舒适的声环境，除了降低声压级之外，优化牙钻声响的频率成分同样至关重要。