Whilst dental operating microscopes can provide staggering levels of magnification, many routine dental procedures can be performed well with high quality dental loupes.
When compared to a dental microscope, loupes are less expensive and easier to use. They are also more portable, practical and an excellent flexible alternative to a microscope for procedures requiring less magnification.
The main benefit in using loupes is that they enlarge the image allowing the clinician to observe structures not easily visible to the naked eye. Practically, magnification allows better precision e.g. during crown preparation, or caries removal. Magnification between 2.0 and 6.0 X are routinely available. The level of magnification depends upon the type of procedure being undertaken. For general dental procedures, 2.5 to 3.5 X magnifications are usually sufficient; whilst for periodontal plastic surgery, crown and bridgework and endodontics higher magnifications of 4.5X and 6.0 X may be desired.
A number of features should be considered when purchasing surgical loupes. First and foremost, the resolution of the loupes is critically important. Resolution is the ability to distinguish one small structure from another. The design and quality of the lenses used in manufacturing the loupes will influence the resolution. This makes resolution the primary factor in determining the overall quality of the loupe. The prospective purchaser should be aware that some lenses will provide excellent resolution across a portion but not necessarily the entire field of view. It is difficult to establish the resolution of the instrument without trying on the loupes and comparing them to others. It is important therefore that the clinician request a trial period to assess whether or not a particular instrument will meet their needs.
Which Are The Best: Through The Lens [TTL] Or Flip-Up Loupes?
There are basically two designs of loupes: Through the Lens loupes [TTL], and those with a flip-up design. With TTL loupes the telescopes are fixed directly to the lens of the glasses.
TTL loupes offer the following advantages over flip-up design:
- TTL normally weigh less than the equivalent magnification flip-up design.
- TTL offer a wider field of view than a similar magnification Flip- up design. This is because the magnification telescopes are mounted closer to the eye.
- TTL loupes are manufactured for each individual – they are custom fit. The angle of declination is set at the factory and therefore there is no need to adjust the angle of declination. They allow the clinician to quickly adopt the most ergonomic position without having to adjust the declination angle.
- TTL loupes are generally lighter than their flip-up equivalents. Furthermore the weight is distributed more evenly.
- They fit more comfortably.
The following are the disadvantages of TTL loupes:
- They generally cost more than the equivalent magnification flip-up loupes.
- If you wear prescription glasses and choose to have the prescription incorporated into the lens of the glasses; should your prescription change, the loupes need to be sent to the manufacturer to be modified. This might involve further cost and will mean that you will be without loupes during the period in which they are being modified.
- When communicating with patients TTL loupes could do with being removed. This can be inconvenient. Alternatively it is possible to look over the telescopes.
- Can only be used for the clinician they were prescribed for.
Flip-up loupes have the magnification telescopes mounted on a hinge system. This means the telescopes can be easily flipped-up when not in use.
The advantages of the flip-up loupes include:
- They cost significantly less than TTL loupes.
- They can easily be flipped up when communicating with the patient, or carrying out other routine tasks in the surgery such as paperwork.
- Flip- up loupes are not operator specific and can be shared between multiple operators. The angle of declination is not fixed and can be modified by each user.
- If prescription lenses are incorporated into the glasses, if the clinician’s prescription changes they can be changed by an optician. Of course with prescription lenses the loupes can only be used by the operator they were customised for and not by the remainder of the dental team.
The disadvantages of flip-up loupes include:
- The angle of declination can be adjusted incorrectly, causing strain on the eyes and/or the musculoskeletal system.
- Depending upon the magnification, flip-up loupes typically weigh more than their TTL equivalents.
- Flip-up loupes have a narrower field of view than TTL loupes. This is because the telescopes are mounted further away from the eyes.
Which Are The Best: Through The Lens (TTL) or Flip-Up Loupes?
Galilean or Class II Loupes are named after the 17th Century astronomer Galileo Galilei. They consist of 3 lenses and are capable of magnifications ranging from 2.0 to 3.5X. With Galilean Loupes the image is sharpest within the central circle. Galilean Loupes are lightweight, affordable and easy to use.
Prismatic or Keplerian Loupes
or Class IV Loupes are based on the Keplerian Design named after Johannes Kepler, the 17 Century astronomer. The Loupe consists of a compound system of several lenses. The advantages of prismatic lenses are a superior resolution over Galilean equivalents throughout the field of vision. Since there are more lenses in prismatic loupes they have longer telescopes and tend to be slightly heavier.
The most effective way for a clinician to measure the effectiveness of a magnification system is to try it in their own surgery. Many companies will offer free trial periods to try out loupes. Whenever possible take advantage of these trial periods to determine the best system for you.