Hand-arm vibration syndrome in dentistry: a questionnaire survey among dentists and review of literature

Early studies have shown that dental professionals exposed to high-frequency dental tools have shown

Presentation Plan The prevalence of MSK disorders is high among all dental professionals and has been studied worldwide, leading to serious impact on quality of life.• Females show a higher prevalence than males in some studies.
• Use of dental tools are related to repetitive movements of the hand and fingers, pinch force, static and asymmetrical posture, precise hand movements, awkward postures of the wrist, high-frequency vibration, as well as other factors, such as poor visibility, lack of breaks between patients and high job demand.
I C H A V 6 / 9 J U N E 2 0 2 3 -N A N C Y -F R A N C E Background • Handpieces and ultrasonic scalers expose dental professionals to highfrequency mechanical vibration, ranging from 0.5 kHz to 50 kHz.• Air turbines and micromotor handpieces are used for tooth preparation, removal of decays, root canal treatments, restorations, implants surgery, bone cutting procedures and various other procedures.• Traditional handpieces are either air-driven or electrically driven, running with high or low-speed.
• High-speed electric handpieces operate in the range of 200,000 rpm.
• High speed air-driven handpieces: up to 400,000 rpm.
• Low-speed handpieces used for polishing and removing decays between 20,000 rpm to 40,000 rpm.
• Gear reduction of speed used in low-speed micromotor.

Background
• Sonic and ultrasonic scalers are frequently used by dentists, specialists and dental hygienists for periodontal procedures.
• They operate in a wide range of frequencies:  Around 3-8 kHz for sonic scalers  18-45 kHz for piezoelectric ultrasonic scalers  25-50 kHz for magnetostrictive scalers Early studies have shown that dental professionals exposed to high-frequency dental tools have shown neurological and vascular symptoms, especially in the dominant hand, comparable to hand-arm vibration syndrome dating back to 1980 .
It is unclear from current research as to whether the handpiece vibration causes ''white finger'' in dental personnel.
Research is needed to aid in the development, design and production of an ultrasonic handpiece that will eliminate any vibration hazards to the operator.

Results of Vibration Assessment
• Handpieces are mostly studied for their cutting & torque efficiency, noise & pinch force or tool handle shape for non-vibrating curettes.
• Information on vibration characteristics of dental handpieces is sparse.
• Vibration assessment is challenging: high frequency of oscillation & small associated displacement amplitude, technical problems relating to the adding mass of the accelerometer, replication of actual work during restorative procedures & periodontal work.
• Interpretation of results due frequency weighting giving more importance to low-frequency vibration.
Hjortsberg 1989: High-Speed Grinders, 30,000 rpm • Neither the water and air injection nor the grip force of fingers had any significant effect on the vibration level.• During idling, the weighted vibration of used micromotor handpieces was on average twice as high as that of the new ones.• During drilling, the ultravibration was one to six fold compared with idling.
• Drilling increase the vibration of handpieces and the vibration became more broadband.
Scanning laser vibrometer for assessing dental ultrasonic scalers is still at an early stage of development.
Vibration patterns are difficult to quantify due to their high frequency of oscillation.
The oscillation patterns along the length of the scaling tip do vary with water flow rate and power setting.
The tip produces a node (point of zero movement) at 4 mm from the free end of the tip.
Poole, 2002, 2004 Results of the survey among dentists   8) for each subject,1 study with mean cumulative exposure mh/s² Higher frequency in dentists/pharmacists (p < 0.05) (Milerad,1990) No increase of vascular symptoms in the groups exposed to vibration vs non-exposed (Akesson,1995) Significant positive correlation: prevalence and frequency of cold sensation and daily usage time (h) (Yoshida,1991) 1 st and 2 nd fingers in hand holding handpiece (Jaques & Burke,1994)  • Prevalence: 0-94% numbness, clumsiness, loss of dexterity, reduced sensibility, tingling • Difficult to distinguish neurological disorder from CTS  Dentists with long term experience had neurological symptoms in the D hand more often than short term (Ekenvall,1990)  Dentists vs pharmacists: RR: 4.2 (CI 95%: 2.3-7.7)(Milerad,1990)  Women reported more sensorineural disorders OR: 2.6 (CI 95%: 1.06-6.7)(Zoidaki,2013)  Numbness & tingling increase with each hr per week vibrating tools (Morse,2003)  Increase risk of high vs low total time dental filling &root canal OR:1.9 (CI 95%: 1.03-3.6)(Rytkönen,2006)  Sensorineural symptoms in dentists: root canal (manual vs.rotor) OR: 3.4 (CI 95%: 1.08-10.9)(Zoidaki, 2013)  Significant positive correlation: prevalence and frequency of numbness and the daily usage time (h) of highspeed type machines (Yoshida,1991) Neurological Disorder Raised VPT and abnormal tests  Dentists (Lundström and Lindmark, 1982, Ekenvall,1990, Akesson, 1995)  Dental hygienists (Akesson,1995, Conrad,1993, Cherniak,2006, Warren 2010)  Dental technicians (Hjortsberg,1989) -Significant difference between left hands of the dentists and both hands of controls (Lundström,1982) -Some association between the years of work and vibration thresholds Increased warming & cooling threshold (Hjorstberg, 1989, Shabazian, 2009), negative (Ekenvall, 1990) Survey among dentists-Société Dentaire de Québec • Short self-administered questionnaire • Presentation during a annual meeting • Email to 350 dentists • Data collection from september 2016-january 2017 Publication in Dental Journal, August 2016 recorded during normal work in one direction Non-contact vibration during idling with Portable Digital VibrometerI C H A V 6 / 9 J U N E 2 0 2 3 -N A N C Y -F R A N C E During work• The weighted vibrations of air-turbine handpieces: 0.01-0.04m/s² • The weighted vibrations of micromotor handpieces: 0.2-0.9m/s² • The drilling time per one patient varied from 0.2 to 4.5 min, which means that the daily vibration exposure time of dentists is below 2,5m/s² (assuming vibration equal in all 3 directions) A V 6 / 9 J U N E 2 0 2 3 -N A N C Y -F R A N C E 13 studies (1 abstract) • Year: 1989-2021 • Dental hygienists & students, dentists, dental technicians• Study design: Cross-sectional (n = 7), case-control (n = 3), survey among workers seeking compensation (n = 1), longitudinal (n = 1) • Methods: Self-administered questionnaire, SK staging Q, cold provocation test (n = 2) • Prevalence of symptoms: 1,9%-80% sectional, observational intervention study, case-control ,1995-2016   • Dentists, dental hygienists, dental technicians Hand weakness (37,5%-85%), lower grip strength vs control group  Significant associations between the full hand grip and the Sensibility Index (SI) of the little finger of the dominant hand within the dentist group  The pinch grip was significantly associated with the SI for the index finger of the dominant hand  Finger pinch force inversely associated with the finger symptoms  Dental hygienist subgroup with a combination of subjective hand weakness, low calibrated pinch force in task simulations, paresthesias, and raised VPTs I C H A V 6 / 9 J U N E 2 0 2 3 -N A N C Y -F R A N C E • In dental students: No significant differences in nerve conduction study between dental students exposed to hand-held vibrating tools for 2 to 6.5 years and medical residents not exposed to vibration(Limbu.2020)