Stay Sharp Series, Part 2: Comparing In-Office Sharpening Systems

Welcome to Part 2 of the Stay Sharp series!! Let’s start first by defining critical components of successful and sustainable in-office sharpening, and use those criteria to compare various in-office sharpening systems.

Below, the table provides a quick visual synopsis of article highlights. Be sure to bring this chart to your next team meeting for team alignment. Review the characteristics of effective sharpening, the expanding explanations that follow, and discuss with your team the importance of each in your practice.

Ineffective Instrument Maintenance

Systems: Nordent InstRenew® Traditional Stones Ceramic Stones Battery-operated Diamond Cards Angulation Guides
Expectations: Nordent InstRenew® product Traditional Stones product Ceramic Stones product Battery-operated product Diamond Cards product Angulation Guides product
Fool-Proof Zero manual angulation, anyone can use
Quick Electric, diamond sharpening
Efficient 1 unit sufficient for virtually any practice
Long-Lasting Will not wear into grooves with use
Versatile Sharpens hoes and explorers
Less Hazardous Less risk of hand injury

Expanded Discussions: Effective In-Office Sharpening Systems Are:

Fool-Proof: An ideal sharpening system requires zero manual angulation before or during sharpening strokes. While hygienists receive some training in instrument angulation techniques, other team members usually do not. Therefore, any system that requires in-depth knowledge of manual sharpening angulation will likely eliminate the potential for team efforts in instrument care. This means that instruments will only be sharpened by clinicians, creating excess payroll expenses and/or reducing productive chair time. Moreover, it is unlikely that even a trained clinician can truly maintain perfect angulation while sharpening; after all, the accuracy and proper angulation of cutting edges is measured on microscopic levels.1 Deviation from the correct stone or instrument angle while sharpening results in lateral bevels that are either too narrow (and can gouge root surfaces2 or break), or too wide (and do no engage calculus deposits properly (burnishing and leaving behind deposits). While there are a few adjunctive sharpening guides to be used with stones that provide “stops” or “rests” for terminal shanks, those methods do not lock the angle in place, which means that angulation will still vary, dependent upon the technique and stability of the clinician. This will not produce consistent cutting edges, and can lead to more sharpening than necessary during testing with acrylic sticks, or over the lifetime of the curette in general. The Nordent InstRenew® was made with this in mind; it ensures every scaler, from area-specifics to universals, stays locked in with correct angulation throughout sharpening. It is currently the only system available offering secure locked angulation during sharpening.

Quick: Real-world dentistry moves at a dizzying pace. Team members often only have a few moments in between procedures to disinfect operatories and prepare for incoming patients. This means that sharpening throughout the day is typically impractical and time-consuming. Even when staff does have an opportunity to sharpen, frequently this time is limited to less than 1 hour. What’s more, instruments become dull after as little as 15-45 strokes,3 meaning weekly sharpening, at minimum, is ideal. During the limited time found or provided weekly for this task, staff needs to be able to sharpen all instruments within the hygiene department effectively. This is only achievable in such short time frames with diamond, electric-sharpening systems. Other methods require many manual strokes, or employ very fine stones; this can delay the creation of sharp cutting edges and keep the practice from successfully maintaining ideal armamentarium. Currently, the Nordent InstRenew® is the only system with electric, diamond-surface sharpening, providing a sharpening pace that can keep up with even the busiest practices.

Less Hazardous: While the ultimate measure of safety with any sharpening system involves proper recommended technique by the operator, some systems involve more relative risk of injury than others. Most systems are hand-held and small, requiring both hands be in very close proximity while engaging in sharpening strokes, and involve risk for clinician hand injury and sticks. The Nordent InstRenew® is currently the only available system which is not manually stabilized while instruments are sharpened in the other hand. Rather, it stands on its own, with sufficient weight to remain still during sharpening. Therefore, the non-dominant hand simply acts as a support to the dominant hand, and both hands move together during sharpening, rather than one hand moving the cutting edge towards the other, like many other available systems. This means that clinicians have a much lower risk of ever cutting themselves during sharpening.

Efficient: Dental overhead costs are notoriously high, creating budgetary restrictions which can be challenging and can lead to inadequate equipment purchases and maintenance. Because the InstRenew® provides such time-saving functionality, one unit purchase provides adequate support for virtually any size team. Each clinician can spend one hour a week and fully restore cutting edges to his/her instruments, freeing up time for other clinicians during other hours and days. Many stone-sharpening systems (especially those not electrically-powered) would sharpen too slowly for complete armamentarium maintenance in just one session or day. Often this leads to larger hygiene departments needing to invest in multiple duplicate products and systems for adequate clinician access.

Long-Lasting: Traditional sharpening stones tend to become worn down in areas of frequent use; this is especially true of powered devices. What’s more, the powered devices which employ traditional stone sharpening surfaces use very small stones, and thus need stone replacement more often than those devices which feature diamond or large surfaces. Often, these grooves worn into the traditional stone surfaces can cause slippage or improper adaptation to the sharpening surface throughout the sharpening stroke. This can cause inconsistencies in blade thickness, bevel angle, and proper use while scaling. The InstRenew® features diamond-coated sharpening cones, which eliminates the issue of surface grooves. It also provides locked angulation, which prevents interference with proper adaptation. Diamond sharpening cards are also available for those practices who want a sharpening aid inside of each cassette.

Versatile: In many practices, hygienists are using a wide variety of scaling instruments, from air polishers to ultrasonics, and from plastic implant scalers to subgingival files. While most sharpening systems available can sharpen traditional scaler types, rounded manual stones and Nordent’s InstRenew® can also sharpen hoes and explorers. Hoes are huge time-savers during lingual hand scaling, eliminating precious minutes from stain or tartar removal at lower front teeth. It is important to select a system for your practice which quickly and effectively sharpens all your scalers.

Mess-Free: Traditional sharpening stones require oil lubricant during use, in order to reduce the embedding of metal shavings from curettes. This creates “slurry” or “sludge” on the stone’s surface, which can actually reduce effective contact with cutting edges and impede sharpening.4 Ceramic stones do not require this lubrication, although the use of water to lubricate them is often recommended. Altogether this may delay a team member from picking up those systems in between two procedures and sharpening even just a few instruments. In real-world dentistry, mess-free solutions are needed. Diamond cards, systems with synthetic stones, and Nordent’s InstRenew® all eliminate the need for oil lubricants, and encourage mess-free sharpening anytime.

By now you and your team are thoroughly educated on the various systems available for instrument care; the only task remaining is to follow through with selection, purchase, and implementation. Before you decide, though, a thoughtful cost analysis is in order. After all, even the best systems must be cost-effective. With each step, your practice will be increasingly prepared for this critical practice optimization decision, and your staff will share a confidence in maintaining equipment to the highest quality standards.


1. Di Fiore A, Mazzoleni S, Fantin F, Favero L, De Francesco M, Stellini E. Evaluation of three different manual techniques of sharpening curettes through a scanning electron microscope: a randomized controlled experimental study. Int J Dent Hyg. 2015 May;13(2):145-50. doi: 10.1111/idh.12109. Epub 2014 Nov 9. PMID: 25382386.

2. Ghilzon, Dr. Romanita. Instrument Sharpening. University of Toronto Faculty of Dentistry.

3. Daniel SJ, Harfst SA, Wilder RS. Mosby’s Dental Hygiene Concepts, Cases and Competencies. 2nd ed. Philadelphia: Mosby Elsevier; 2008.

4. Gleason, Roger. The Elusive Edge, sharpening shouldn’t be so difficult, and here’s a guide to success. Dentistry IQ. 30March 2015.