A dental torque wrench or restorative torque wrench is a

torque wrench A torque wrench is a tool used to apply a specific torque to a fastener such as a nut, bolt, or lag screw. It is usually in the form of a socket wrench with an indicating scale, or an internal mechanism which will indicate (as by 'clicking', a ...

used to precisely apply a specific

torque In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...

to a fastener bolt for fixation of an

abutment An abutment is the substructure at the ends of a bridge span or dam supporting its superstructure. Single-span bridges have abutments at each end which provide vertical and lateral support for the span, as well as acting as retaining walls ...

dentures Dentures (also known as false teeth) are prosthetic devices constructed to replace missing teeth, and are supported by the surrounding soft and hard tissues of the oral cavity. Conventional dentures are removable ( removable partial denture o ...

or prosthetics on a

dental implant A dental implant (also known as an endosseous implant or fixture) is a prosthesis that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown, bridge, denture, or facial prosthesis or to act as an orthodo ...

Manual mechanical torque wrench

Toggle torque wrenches ( friction-style) and beam wrenches ( spring-style) are the most common types in

dentistry Dentistry, also known as dental medicine and oral medicine, is the branch of medicine focused on the teeth, gums, and mouth. It consists of the study, diagnosis, prevention, management, and treatment of diseases, disorders, and conditions o ...

as manual mechanical torque-limiting devices. Beam type wrenches in general are more consistent to its calibration than toggle types. The beam types with a dial indicator are the most precise to set the Tare torque (zero point reset). Because steam sterilization processes like an

autoclave An autoclave is a machine used to carry out industrial and scientific processes requiring elevated temperature and pressure in relation to ambient pressure and/or temperature. Autoclaves are used before surgical procedures to perform sterilizati ...

are applied to the dental torque wrenches and the length of time in use presents stress on the material, fatigue can occur.

Surgical motor

The surgical motor is an

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controlled torque-limiting device that also controls the speed. It is used with a twisted drill to make space in the bone for the implant or to fasten the screw (torque control can be with a torque-limiting attachment) with a screwdriver bit. In high precision areas such as aerospace applications motor or pneumatic torque wrenches are set at a lower torque value after which the final torque is set with a manual mechanical torque wrench, they are calibrated before every use, if a wrench breaks or loses calibration every fastener done with that wrench is redone.

Calibration

Various studies point to deviations of 10% and higher than the desired torque, regular recalibration with a

torque tester A torque tester is used as a quality control device to test or calibrate torque controlled tools. This includes electronic torque wrenches, click torque wrenches, dial torque wrenches, electric screwdrivers, air screwdrivers, pulse tools, cordless s ...

restores the required torque values.

Re-torquing

As the settling effect (the flattening of the material's micro-surface under pressure) causes a lesser torque of around 10% in a relative short time, re-torquing the fastener after 10 minutes reduces this effect as the parts get more seated.

Wet and dry torque

Wet torques (bolts lubricated with

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) have a higher mean torque than dry torques (unlubricated).

References