Terri Lively

This Bioactive Filler Had Better Polymerization Kinetics, Study Says. Photo courtesy of Valerii Honcharuk/stock.adobe.com. 


Bioactive composite materials help prevent secondary caries in a restored tooth. However, the additives that benefit the hard tissues and optimize the tooth also affect the polymerization process, not in a good way. An October 2021 Study in 

 looked at a lower sodium version of a bioactive glass that might have the benefits of a bioactive filler without inhibiting polymerization results or rates.

The study, "Polymerization kinetics of experimental resin composites functionalized with conventional (45S5) and a customized low-sodium fluoride-containing bioactive glass," investigated how the 2 bioactive glasses (BG) performed. One is the BG 45S5, and the other is a low-sodium (Na Fluoride (F)-containing BG). While the BG 45S5 did slow the polymerization rate and inhibit the final results, the Low-Na F-containing BG showed a negligible influence compared to controls.

The following summarizes who did the research, why, what they thought would happen, how they did it, and what they learned.

Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Zagreb, Croatia

 Department of Conservative and Preventive Dentistry, Centre for Dental Medicine, University of Zurich, Zurich, Switzerland

, Department of Endodontics and Restorative Dentistry, School of Dental Medicine, University of Zagreb, Zagreb, Croatia

Why Did They Test the 2 Bioactive Glass Fillers for Their Effect on Polymerization Kinetics?

Bioactive materials are useful in dentistry. The restorative material's ability to positively affect the surrounding dentition is a feature that piques many dentists' curiosity.

A bioactive material evokes a response from the living tissue, organisms, or a cell, including the formation of hydroxyapatite, per the 

International Journal of Contemporary Dental and Medical Reviews. 

The ideal properties of bioactive materials are that it kills bacteria as well as prevent their formation, it is sterile, it stimulates dentine formation, and it maintains the pulp of the tooth. Clinicians use bioactive materials for pulp capping, permanent restorative dentistry, dentinal tubule occlusion, regenerating bone, and tooth remineralization.

Bioactive materials can help prevent secondary caries that cause composite resin restorative failures, sometimes in otherwise sound restorations. So, materials development teams started putting reactive additives to protect the hard tissue of a restored tooth from decay. By discouraging bacteria formation to inhibiting and promoting remineralization to improve the restorative seal, these additives provided many benefits to restorations. The bioactive glasses are one the most capable ones.

However, some bioactive glasses (BG 45S5) used have inhibited polymerization kinetics, both in the result and polymerization speed. The rate of polymerization kinetics affects the resulting polymers chain length, composition, distribution, and tacticity.

 The polymerization rate is essential to optimize because all the polymer's properties, chemical, mechanical, and physical, depending on the tacticity, a term that describes the arrangement of the groups on the hydrocarbon chain.

Because of the benefits of the BG on the composites, the researchers wanted to determine if the alternative for BG 45S5, Low-Na F-Containing BG, would provide the benefits without adverse effects on the polymerization kinetics of the materials.

In other words, they wanted to see if they could keep all the pros of the initial BG material and eliminate its cons by replacing it with a new experimental version.

The polymerization kinetics would not affect the composite layer's type, amount, or thickness.

The curing light's transmittance through 2mm would not be affected by either type or amount.

The researchers started by using a similar preparation and grinding for the fillers to ensure similar particle sizes of the BG filler materials and the control. Then, they mixed the BG fillers in a 60:40 mixture of bisphenol-A-glycidyl methacrylate (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA). Then, they added the photoinitiators, camphorquinone, and dimethylamino benzoate and blended them in a dark container for two days. Alongside the ones they mixed just for the experiment, they also used Charisma Classic (Kulzer) as a reference.

The researchers tested the polymerization kinetics using a degree of conversion measurements using a Fourier transform infrared Spectrometer and an attenuated total reflectance accessory. The materials were placed in 6mm diameter thicknesses of .1mm and 2mm thicknesses and cured for 20 seconds. Then, they collected the FTIR spectra continuously for 5 minutes. Five specimens of each type of composite were tested.

Light transmittance was measured during light curing. First, the team collected the light passing through the specimens with a lens directed into a charge-coupled device array fiber spectrometer. Spectra were gathered at a rate of 20-seconds, the time of light curing. Then they divided this measurement by the light intensity of the empty specimen compartment to get the light transmittance percentage.

Then, the research team did a statistical analysis of the data to determine their results.

The researchers determined that the 2mm thick specimen reduced the light transmittance in both BG types. However, they only observed a reduction in polymerization rate and degree of conversion in the experimental composites with BG 45S5, not Low-Na F-containing BG. Moreover, that rate was affected by the amount of BG 45S5 present in the material. The more of it there was, the more the polymerization rate decreased, as did the degree of conversion.

On the contrary, Low-Na F-Containing BG showed a viable and beneficial filler for light-cured dental resin composites. Furthermore, it showed a negligible influence on polymerization. Although it did result in lower light transmittance, the presence of Low-Na F-Containing BG did not impair the polymerization kinetics.

By comparing the polymerization kinetics between the .1mm and 2mm specimens, the researchers also learned that improving light transmittance for BG 45S5 did not improve polymerization kinetics. This analysis led researchers to believe that the BG 45S5 material directly impacts the polymerization reaction.

So, does that mean that materials developers will switch to a new BG in future materials? It might; it might not. Time will tell. However, the science published here indicates that making a switch to a Low-Na F-containing BG for a filler load in a bioactive resin composite is an opportunity for materials manufacturers to move forward.

1. Par, M., Prskalo, K., Tauböck, T.T. 

 Polymerization kinetics of experimental resin composites functionalized with conventional (45S5) and a customized low-sodium fluoride-containing bioactive glass. 

21225 (2021). https://doi.org/10.1038/s41598-021-00774-w

2. Snehal Sonarkar, Rucheet Purba, "Bioactive materials in conservative dentistry," Int J Contemp Dent Med Rev, vol.2015, Article ID: 340115, 2015. DOI: 10.15713/ins.ijcdmr.47

3. What is Polymerization?. Bartlby.com. Accessed February 14, 2022. https://www.bartleby.com/subject/science/chemistry/concepts/polymerization-kinetics.Jankowski, BSChE, Patricia. Tacticity of Polymers: Definition, Types & Examples. Accessed February 14, 2022. https://study.com/academy/lesson/tacticity-of-polymers-definition-types-examples.html.

4. Jankowski, BSChE, Patricia. Tacticity of Polymers: Definition, Types & Examples. Accessed February 14, 2022. https://study.com/academy/lesson/tacticity-of-polymers-definition-types-examples.html.

Articles

An October 2021 Study in Scientific Reports took a look at a lower sodium version of a bioactive glass that might have the benefits you want without inhibiting polymerization results or rates. 

This Bioactive Filler Had Better Polymerization Kinetics, Study Says

The 1960s were a busy time in materials science. After serving in the United States Army and graduating from USC’s Dental school in 1953, Dr Rafael Bowen joined the American Dental Association’s Research Labs in 1956.

 In the early 1960s, Dr Bowen discovered how to chemically treat particles to bond with polymer-containing substances to create a robust restorative material.

That restorative material is bisphenol A-glycidyl methacrylate (Bis-GMA), and it transformed the practice of dentistry. This composite resin has been used in restorative materials for more than 50 years.

In the late 1960s, a second material—known for its high fluoride release and low solubility—emerged that facilitated minimally invasive preps and improved the restorative seal while reducing microleakage.

 It was a glass ionomer. Now, 60 years later, the material continues to be a workhorse in a dentist’s armamentarium.

Glass ionomer, however, is a misnomer. According to the International Organization for Standardization, the official term for them is “glass polyalkenoate cement,” but no one calls them that. Glass ionomer is the recognized term widely used by dental professionals.

 Glass ionomer cements are polymeric acid, glass, and water. The polymeric acid is either the homopolymer or copolymer of acrylic acid. The glass particles are basic glasses, meaning they react with the acid to form a salt. The glasses used are alumino-silicate glasses with fluoride and phosphate added to them. They are self-setting, using an acid-base reaction.

 Introduced in 1991, resin-modified glass ionomers have the same components, plus a monomer component (usually 2-hydroxyethyl methacrylate) and an initiator (camphoquinone). The “resin” means these materials are set based on an acid-base reaction and polymerization.

 Designed to have additional bioactivity (more on that later), glass carbomer is a type of glass ionomer. The difference is that there are other materials present, including a bioactive component that behaves as a secondary filler. To set, it has 2 modified acid-base reactions, one with the acid and the glass filler and another with the hydroxyapatite filler. A curing light is used with this material, but not for polymerization. Instead, the curing light increases the temperature of the material to speed up the set time.

Glass ionomers are known for their versatility in the operatory. There are quite a few things they do for restorative work:

They are biocompatible and release biologically beneficial ions into the surrounding fluid, which can reduce the pH of the patient’s mouth and promote remineralization of the tooth.

They can release fluoride, which can help prevent future caries and inhibit the demineralization of teeth.

They adhere to the tooth’s surface chemically and through micromechanical interlocking rather than an adhesive system.

They match the natural tissue for the coefficient of thermal expansion.

Glass ionomer cements are also known for what they don’t do:

They don’t have a problem with polymerization shrinkage.

They don’t have a problem with areas challenging to isolate from fluids.

They don’t cause as much postoperative sensitivity as their composite resin counterparts.

There are many clinical situations where glass ionomers, resin-modified glass ionomers, or glass carbomers might benefit the restorations. For example, a 2002 position paper on glass ionomer cement in 

 stated that the literature supports the following uses for the materials:

 Whether for stainless steel crowns, orthodontic bands, or orthodontic brackets (although limited on this one), the enhanced physical properties and easy handling make glass ionomer cements a good choice.

 The best formulations are highly flowable, low-viscosity versions of the materials to get into the areas that need additional protection, sealing, or retention properties.

Class I, II, III, and V restorations in primary teeth: 

Depending on the prep, these materials are ideal choices for these restorations for children for their hydrophobic and self-cure properties.

Class III and V restorations in permanent teeth: 

Especially for high-risk patients or patients’ teeth that cannot be isolated enough for other materials, these can be great restorative material choices.

When you have high-risk patients, repairs of restorations, and atraumatic restorative treatments, these materials’ properties can help prevent future decay.

However, glass ionomers, resin-modified glass ionomers, and glass carbomers are not only for primary dentition. In his “20 Tips for Using Glass Ionomers” for the American Academy of Cosmetic Dentistry, Daniel Ward, DDS, explains that there are some uses for permanent dentition and grown-ups:

 For patients who need to delay a crown, use a glass ionomer in bulk to maintain tooth structure for future crown prep.

Resin-modified glass ionomers can serve as a provisional protecting the cusps until you can place a crown.

Restoring cervical lesions for patients on multiple medications

: Placing glass ionomers can reduce recurrent decay for patients experiencing xerostomia.

 A self-curing glass ionomer can have multiple benefits for small- to medium-sized buildups, such as reducing postoperative sensitivity, protecting against recurrent decay, and providing a stable bond and long-term retention.

 This method can help older patients who have decay around a crown but cannot sit through long treatments.

 Using resin-modified glass ionomers under a deep composite restoration can help relieve pain and sensitivity and provide fluoride to protect against decay due to marginal leakage.

Improving the appearance of class V restorations: 

Resin-modified glass ionomers have better aesthetics than self-curing glass ionomers and have better retention rates than composites that require dentin bonding systems.

Improving physical properties in contaminated preps:

 When you cannot keep it dry for a minute or more, resin-modified glass ionomers will not affect the dentinal bond or the material’s physical properties once it is cured.

Using glass ionomers or resin-modified glass ionomers and glass carbomers has a lot of benefits. Perhaps one of the manufacturers of the bioactive glass powders says it best, that unlike some other materials used in restorative dentistry, glass ionomers become stronger over time as they absorb water and are less likely to fail. However, from a practical perspective, perhaps the most significant reason to use glass ionomers is the chemical bond they make with the tooth, requiring no bonding agent.

 have a different take. The bioactivity of glass ionomers creates an interfacial ion-exchange layer with the patient’s tooth, contributing to the durable bond. Glass ionomers also release fluoride for a long time, which isn’t proven to help, but certainly can’t hurt.

Dr Berg writes that glass ionomers are an excellent material for use in dental operatories, especially when working with children. He notes that their superb handling, ease of use, self-adhesive properties, fluoride-releasing properties, and love of water make them a mainstay in restorative dentistry.6

Like Dr Berg, Dr Ward agrees that glass ionomers are easy to place and are not as technique sensitive as other restorative materials. While they will never replace composite resin materials, Dr Ward writes that they are a helpful adjunct, and that time and experience will show clinicians how they can be the most beneficial in their hands.7

So, the question is not, “Why glass ionomers?” but instead, “Why not?"

Dr. Rafael Bowen obituary. The Washington Post. April 20, 2020. Accessed March 8, 2022. 

https://www.legacy.com/us/obituaries/washingtonpost/name/rafael-bowen-obituary?id=2021842#:~:text=Bowen%20developed%20Bis%2DGMA%2C%20which,of%20the%20Paffenbarger%20Research%20Institute.

Bayne, SC. Beginnings of the dental composite revolution. 

Wilson, AD. Glass-ionomer cement--origins, development and future. 

Sidhu SK, Nicholson JW. A review of glass-ionomer cements for clinical dentistry. 

Nicholson JW, Sidhu SK, Czarnecka B. Enhancing the mechanical properties of glass-ionomer dental cements: a review. 

Berg, JH. Glass ionomer cements. American Association of Pediatric Dentistry. 2002. Accessed March 1, 2022.


https://www.aapd.org/globalassets/media/publications/archives/berg5-02.pdf

Ward, D. 20 Tips for using glass ionomers: How to use dentistry’s other tooth-colored materials. American Academy of Cosmetic Dentistry. 2011. Accessed March 1, 2022. 

https://aacd.com/proxy.php?filename=files/Students%20and%20Faculty/20%20tips%20Glass%20Ionomers.pdf

The advantages of using glass ionomers in dentistry. News Medical Life Sciences. July 10, 2018. Accessed March 1, 2022. 

https://www.news-medical.net/whitepaper/20180710/The-Advantages-of-Using-Glass-Ionomers-in-Dentistry.aspx

60 years on, the material continues to be a workhorse in a dentist’s armamentarium.

The Who, What, When, Where, Why, and How of Glass Ionomers 

Getting Direct about Indirect Dental Restorative Materials: Why Ceramics and Resins Are Leading Development. Photo courtesy of metr1c/stock.adobe.com. 


In the old days, there weren’t a lot of options for replacing indirect restorations. Or maybe there were, if you think all the animals’ teeth in the animal kingdom were an option, or maybe just their tusks. Of course, you could always get human teeth to replace the missing ones in a mouth, provided there had a been a good haul from the poor districts or a giant battle with lots of casualties in a field nearby.

Luckily, we don’t have to resort to such macabre measures these days to restore missing teeth. Several materials exist to fabricate indirect restorations. Whether you choose them, or the lab does, we take a look at the different types of indirect materials and why ceramics and resin composites could be what you choose for your next case.

Different Types of Indirect Restorative Materials

Today’s indirect materials break down into the following categories and usages:

: Inlays, onlays, crowns, fixed bridges, and infrastructures

 Inlays, onlays, crowns, esthetic veneers

 Inlays, onlays, and long-term temporaries

Each indirect material has advantages and disadvantages, indications and contraindications, per the American Dental Association (ADA). There are also 4 considerations about your indirect materials that should go into the materials selection decision: composition, physical and mechanical properties, processing methods, and clinical indications.

 Of course, patients would likely add a fifth consideration, cost.

 (To be fair, many clinicians would, too.)

There are more clinical considerations regarding material choices for an indirect restoration, too. These include things like the tooth location, the amount of tooth that will show when the patient smiles, the position of the patient’s gum, what the tooth needs to do, how much natural tooth remains, and the appearance of the surrounding dentition.

For example, if you are placing an implant and need to choose a crown material, you would determine what you want the restored tooth to do, the mechanical properties of the material you use and how it will hold up at that position. A temporary crown or restoration to allow the patient’s bone time to heal before placing the permanent one might lead you to select composite-resin. However, if you don’t need a temporary first, you might pick a porcelain-fused-to-metal or an all-ceramic material, like zirconia, instead.

Of course, you might not choose one at all and let your lab technician partner decide, which is also a great solution. It’s all in how you want to work.

The different materials are associated with specific longevity rates. Not surprisingly, gold, and the other metal and metal alloy restorations, have the longest survival rate, with an average of around 20 years, and in some cases double that, and the lowest annual failure rate. Next came, the metal-ceramic crowns, which averaged 10-25 years. Zirconia and feldspathic porcelain (a glass material with a non-crystalline structure) came in at 10 years.

 CAD/CAM materials (single tooth), lithium disilicate or leucite reinforced, glass infiltrated ceramics, and resin composites all had a survival rate of 5 years. There is a comprehensive overview from the ADA on indirect materials if you want to learn more about your choices, use cases, advantage and disadvantages, and survivability and longevity rates.

Ceramics and Resin Composites Are Driving the Indirect Material Development Game

Historically, the choices for indirect restorative materials were a bit easier because of the dearth of options. Clinicians used metals for the restorations because metals were strong and lasted a long time. Even today, after the advent of more esthetic materials than metal, the ADA describes metals, like gold, base metal alloys, and even amalgam as useful restorative materials.

 The ADA’s report from the science and research institute describes high noble alloys (like gold) as “the standard by which other dental materials are judged.”

However, despite the performance of metals like gold, people started wanting tooth-colored restorations, which metal could not deliver, but ceramics could. Unfortunately, ceramic materials could also fracture and couldn’t last as long as the metal restorations did. Regardless of the shortcomings for longevity and strength, materials manufacturers developed many different ceramic materials options from which to choose. These include glass-ceramics, porcelain, and polycrystalline ceramics.

Porcelain fused-to-metal systems were introduced in the mid-twentieth century. Later in the early 60s, incorporating more leucite crystals into the feldspathic porcelain’s makeup increased the strength of the restorations. The leucite crystals increased the thermal expansion of the porcelain, matching it closer with the metal substrate. This enhancement created strong restorations.

Early ceramic restorative materials often had clinicians choosing between those that were strong or those that looked good. However, materials science has advanced to the point today that many of dental newer ceramic indirect materials are strong and esthetic. Also, ceramic materials appealed to clinicians because of their biocompatibility and chemical stability.

 Moreover, computer-aided fabrication techniques are advancing all the time, which increased the popularity of all-ceramic indirect restorations. The classes of ceramics for use in CAD/CAM processing are zirconia, glass ceramics, and resin-ceramic composites.

 Zirconia and lithium disilicate are 2 of the most popular all-ceramic materials today.

However, ceramics are not the only tooth-colored options for indirect restorations. There are also the resin-matrix composites, which are known for their easy-to-manipulate characteristics. However, indirect resin-matrix composites differ from direct restoration composites because these materials often have higher filler loads and higher degrees of polymerization than the direct versions. Also, indirect restorative composites have fewer problems with polymerization shrinkage since they are cured outside the patient’s mouth. In addition, the CAD/CAM blocks of it are more biocompatible than their direct composite counterparts because manufacturers’ use different resins for the block versions. Plus, these indirect CAD/CAM composite versions demonstrate more resistance to degrading and leaking, have more flexibility during chewing forces, and are less abrasive to opposing dentition. However, they also tend to have lower flexural strength and fracture toughness. These indirect composites are usually made of urethan dimethacrylate (UDMA), triethylene glycol dimethacrylate (TEGMDA), or Bis-GMA bisphenol A-glycidyl methacrylate for the matrix, and silica, silica-based glasses, glass-ceramics, zirconia, or zirconia-silica ceramic for the fillers.

Ceramics and resin-based composites tend to be popular for indirect restorations because of their composition and characteristics. For example, all-ceramic indirect restorations are an excellent choice when you are placing crowns, inlays, onlays, veneers and bridges.

 Resin composites have been widely recommended as long-term provisional restorations.

 Also, some evidence suggests that resin composites can offer a better-looking material for posterior indirect restorations, and in some cases, might offer a better solution than ceramics for some patients’ crowns, particularly to absorb chewing stresses in implants when the patient has poor periodontal structures supporting the restoration.

For full-arch cases, however, some dentists prefer all-ceramic materials, like zirconia, to resin composites. In these high-priced, full-mouth restorative treatments, clinicians favor the predictable mechanical performance of the ceramics over ceramic-, acrylic-, and resin-metal alloy prostheses. Moreover, improvements to the material compositions in the last few years have created all-ceramic materials that are strong like their predecessors, but much more esthetic. Some other benefits noted are increased accuracy, decreasedveneering porcelain and the need for minimal occlusal adjustments. Also, using a full occlusal monolithic framework and minimal facial cutback can reduce the chipping of the veneered porcelain.

Things have changed for the better with indirect restorative materials, when you consider what was available over the course of history. All of today’s indirect materials have strengths and weaknesses, but the rising popularity of CAD/CAM systems and milling for chairside or lab production of indirect restorations is likely to continue development in the direction of all-ceramic and composite resin materials. 


Materials for Indirect Restorations. Ada.org. Published 2021. Accessed January 31, 2022. https://www.ada.org/resources/research/science-and-research-institute/oral-health-topics/materials-for-indirect-restorations. 

Larson J. Dental Crown Types, Procedure, When It's Done, Cost, and Aftercare. Healthline. Published 2019. Accessed February 11, 2021. https://www.healthline.com/find-care/articles/dentists/dental-crown#types.

Jones, PhD, FIM, CCHem. FRSC, FBSE D. CDA-ADC Journal. Cda-adc.ca. Published 1998. Accessed February 3, 2022. https://www.cda-adc.ca/jcda/vol-64/issue-9/648.html. 

ADA Council on Scientific Affairs. Direct and indirect restorative materials. J Am Dent Assoc. 2003;134(4):463-472. doi:10.14219/jada.archive.2003.019

Materials for Indirect Restorations. Ada.org. Published 2021. Accessed January 31, 2022. https://www.ada.org/resources/research/science-and-research-institute/oral-health-topics/materials-for-indirect-restorations.

Warner B. COMPARE INDIRECT AND DIRECT RESTORATIVE MATERIALS IN DENTISTRY. Blog.ddslab.com. Published 2022. Accessed February 1, 2022. https://blog.ddslab.com/indirect-and-direct-restorative-materials. 

Larson J. Dental Crown Types, Procedure, When It's Done, Cost, and Aftercare. Healthline. Published 2019. Accessed February 1, 2022. https://www.healthline.com/find-care/articles/dentists/dental-crown#types.

Nandini S. Indirect resin composites. J Conserv Dent. 2010;13(4):184-194. doi:10.4103/0972-0707.73377

Winstead, CDT M, Arce, DDS C. Technique: Fabricating full arch implant prosthesis. Dental Products Report. Published 2017. Accessed February 1, 2022. https://www.dentalproductsreport.com/view/technique-fabricating-full-arch-implant-prosthesis. 

We take a look at the different types of indirect dental restorative materials and which ones are likely to be the ones you choose for your next case.

Getting Direct about Indirect Dental Restorative Materials: Why Ceramics and Resins Are Leading Development

As a dental professional, you are no stranger to preparing teeth for bonded direct restorations. In fact, you probably do this all day long every day in your practice. Over time, preparations might become rote, a process so comfortable and familiar that you no longer think about them. However, this habitual process could have room for opportunity. Let’s take a closer look at all the steps you do for prep and why they matter to your bonded direct restoration outcomes.

After anesthesia and before the dentist ever picks up a handpiece, shade matching occurs. Some new one-shade-fits-all materials have rendered this step pointless, as would restorative processes that involve metals. However, most dentists are using dental composite resin these days to deliver tooth-colored restorations to their patients. And for dentists using many universal or traditional restorative dental composite resins, the shade matching step is critical for the end result of the restorative process, particularly in the esthetic zone.

Shade matching requires dentists to consider 3 crucial things: Hue, Value, and Chroma. These are Albert Munsell’s 3 dimensions of color. Hue is the perceived color for the viewer, Value is the brightness of the color, and chroma is the intensity of it. On the VITA™ Shade Guide, the Hue is the letter, and the Chroma is the number.

In addition, there is also a critical consideration in how natural teeth react with light. Therefore,Translucency (how light passes through), Fluorescence (how the light absorbs and then emits), and Opalescence (how light reflects and transmits) should weigh in when matching surrounding dentition.

Science lesson aside, shade matching is critical and requires a proven technique to get it right. The reason the shade matching step is first is because as the restorative process continues, the tooth dries out, which changes the tooth’s shade appearance. The problem here is obvious, once the surrounding dentition rehydrate, your restoration will not match. Therefore, keeping the tooth hydrated while shade matching is critical. Using a natural light source is another excellent way to get the best match. Also, use the shade guide that corresponds to the materials you use rather than a universal shade guide (and make sure it isn’t one that you have had lying around for a long time or disinfected a bunch of times).

To learn more about shade matching, read 

Shade Secrets: Best Dental Practices for Getting Your Shade Matching Correct.

Before you rebuild the patient’s occlusion, you have to know what the patient already had. The British Dental Journal has a handy acronym to help with this, Examine, Design, Execute, Check, or EDEC. It starts by asking the patient to bite down on a thin articulating paper or foil to get both a static and dynamic occlusion mark. Then, visualize how this information affects the cavity preparation. Next, you execute the cavity prep. Finally, after the restoration, you ensure that the occlusion of your restoration is the same as the patient’s original occlusion.

To read more about EDEC or the importance of the occlusal check from 

Most bonded composite restorations need a field clear of fluid and contamination to bond properly. This requires excellent isolation of the area you want to restore. Not isolating properly can lead to adverse restorative outcomes that could include sensitivity, contamination, and microleakage.

All dentists know that a rubber dam is effective for isolation of the restorative area. To summarize, it has excellent moisture control, retracts the soft tissue to allow for access to improve interproximal access if necessary, improves patient safety for ingestion of harmful dental materials and instruments, and prevents the transfer of infection. Also, rubber dams provide clinical benefits, including improved access and visibility to the operative procedures. They also protect the soft tissue from sharp instruments and burs, particularly in posterior restorative work. Furthermore, it might provide an enhanced adhesive environment, although that last bit is not 100 percent proven by the literature.

However, there are other options for proper isolation, too, which is great news since many clinicians feel like rubber dams are time consuming to place. The Zyris Isolite® Whole Mouth Solution for example, which includes dental isolation, illumination, and suction. They also have the Isodry® that does keep the area dry, but doesn’t have all the lights.

Of course, there are always cotton rolls and retraction, which some dentists find sufficient. However, a 2016 study from China indicates that rubber dams outperform cotton rolls for increasing dental restorations’ survival time, although the authors thought more study was needed in this area to draw a real conclusion on this point.

To read more about isolation with rubber dams, try 

Why some dentists don’t give a rubber dam—and why some do.

Some dentists will also pre-wedge between the teeth. 

, pre-wedging has a few benefits to your prep. First, it can protect the rubber which can break during cavity prep. Also, it can push the rubber and the gingiva toward the apex. Finally, wedges can separate the teeth in case you need to simplify proximal prep, if needed.

How much tooth you drill and trim varies depending on the restorative treatment you are using. Closing diastemas, fixing chips, or veneering the anterior teeth might not require much trimming. Fixing decayed teeth, sometimes teeth that are extremely damaged, requires more drilling.

Your diagnosis, treatment planning, and past experience will dictate what you do here. However, so should the material you intend to use for the restorative treatment. The way you prep the tooth will facilitate the way you adhere the restorative materials to the remaining natural tooth.

A direct restoration caries prep has 3 main steps. It starts by accessing the tooth, then removing the caries, and then finishing the walls of the cavity you formed.

 Once you have prepared a restoration for composite placement, it's a good idea to check the texture of the convergent walls with a mirror to ensure you have all the decay and that the walls of the prep are smooth. You can also confirm that you got all the caries using an explorer at the base and sides of the prep. Then, you can aid retention of the composite resin material by roughening the enamel walls with a diamond bur.

 In the case where you have a proximal preparation, you might also then apply a metallic matrix and ring for rebuilding the proximal walls.

For some types of caries, using an enamel bevel helps with bonding and also to create a gradual transition from material to healthy tooth. In these cases, retention is also aided by using a diamond bur to roughen the surface for a micromechanical retention of material.

You have to clean the surface before you bond anything. Having debris on the surface will degrade the bond.

suggests that the surface-cleaning technique you use could affect bond strength or composite resin restorations. They compared the occlusal surfaces of 25 molars that were divided into 5 groups depending how they were cleaned, which included microairborne-particle abrasion, alcohol, rubber-rotary instrument, desiccating agent, and control. The microairborne-particle abrasion group was significantly better for cleaning the surface and increasing bond strength.

Many dentists will clean the surface of their preps with other solutions. Some popular ones use chlorhexidine applied before the bonding agent. These solutions will clean away microbials or other contaminants. Moreover, by adhering to the tooth’s prepped surface, it can act like a primer that re-wets the collagen. Then, when the bonding agent is applied afterward, it can bond with the tooth in the dentin. Some popular versions are Cavity Cleanser™ (BISCO) and Consepsis™ (Ultradent Products). Another option is GLUMA® (Kulzer), which acts as a desensitizer as well as an antimicrobial for the prepared surface.

To read more about cleaning and other examples of overlooked steps of direct restoration, 

Bonded direct restorations rely on technique for their longevity and function. It starts by prepping the area properly and following the steps. Of course, the need for technique doesn’t end here, but at least if you made it this far with good technique, you have an excellent foundation on which to build your restoration and provide the highest standard of patient care.

Shade Matching In Restorative Dentistry: The Science And Strategies.

. 1st ed. Pubmed; 2003:4. https://www.researchgate.net/publication/9006870_Shade_matching_in_restorative_dentistry_The_science_and_strategies. Accessed 3 February 2022.

2. Lowe, DDS, FAGD, FICD, FADI, FACD, FIADFE R. Composite Restorations: Subtleties in Shade and Technique. Dentalacademyofce.com. https://dentalacademyofce.com/courses/1972/PDF/1011cei_nuance_web2.pdf. Published 2010. Accessed 3 February 2022.

3. Davies, S., Gray, R. & Smith, P. Good occlusal practice in simple restorative dentistry. 

4. Nasser A. Rubber Dam Isolation - When and Why to Use it? Part 1. 

. 2021;28(2):40-41. doi:10.1038/s41406-021-0201-y

5. Wang Y, Li C, Yuan H, et al. Rubber dam isolation for restorative treatment in dental patients. 

. 2016;9(9):CD009858. Published 2016 Sep 20. doi:10.1002/14651858.CD009858.pub2

6. Lazar D. Back to Basics: A step by step protocol - Styleitaliano.org. Styleitaliano.org. https://www.styleitaliano.org/back-to-basics-a-step-by-step-protocol/. Published 2022. Accessed February 4, 2022.

7. How bonding (dental composite) is placed. – The steps of the procedure. Aftercare and precautions. Animated-teeth.com. https://www.animated-teeth.com/tooth-bonding/a32-dentist-composite-fillings.htm. Accessed February 4, 2022.

Class 1 Composite Preparation & Restoration | Operative Dentistry

.; 2020. https://www.youtube.com/watch?v=9HnK8xOcLW8. Accessed February 4, 2022.

9. Ritter A, Walter R, Roberson T. 9: Class III, IV, and V Direct Composite and Glass Ionomer Restorations. pocketdentistry.com. https://pocketdentistry.com/9-class-iii-iv-and-v-direct-composite-and-glass-ionomer-restorations/. Accessed February 4, 2022.

10. Erkut S, Yilmaz B, Bagis B, Küçükeşmen C, Ozdemir E, Acar O. Effect of different surface-cleaning techniques on the bond strength of composite resin restorations. 

. 2014;112(4):949-956. doi:10.1016/j.prosdent.2014.05.001

We take a detailed look at all the steps you should do for dental preps and why they matter to your bonded direct restoration outcomes.

All the Steps for Preps for Bonded Direct Restorations

Talking About Oral Systemic Health in the Dental Hygiene Room. Photo courtesy of Drazen/stock.adobe.com. 


Research has established a clear association between a patient’s oral disease and other systemic health conditions, referred to as the oral-systemic link. As a prevention specialist, the hygienist seems a natural fit for patient education about this association. We discuss why this education is essential and the hygienist’s role when it comes to teaching patients about mouth-body connections.

The Oral-Systemic Link is essential for patients to understand for a number of reasons. Research shows a link between periodontal disease and systemic conditions like heart disease, stroke, diabetes, and others. Research also suggests there is a connection between periodontal disease and adverse pregnancy outcomes. In addition, the American Dental Association (ADA) says that both periodontal disease and systemic conditions have similar risk factors for disease, like smoking or a poor diet.

Chris Richardson, DMD, MS, President of the American Academy of Periodontology (AAP), says that the oral-systemic link has been a topic of study for a long time, and the AAP has accumulated, along with academic institutions worldwide, plentfiful data regarding the relationship between the health of the oral cavity and the rest of the body. These connected conditions are serious and worthy of a discussion with patients.

“Some of the diseases that can be affected from an unhealthy oral health perspective are systemic issues like diabetes, rheumatoid arthritis, and cardiovascular disease,” Dr Richardson says.

Dr Richardson refers to a December 2021 study in the British Medical Journal, which suggests that patients with periodontitis or bone loss around teeth,have an increased risk for many systemic conditions. The study encompassed nearly 65,000 adults that had reported a history of periodontal disease who were matched to over 250,000 people without gum disease. The systemic diseases for which the periodontitis group demonstrated anincreased risk included:

Mental Health issues, including anxiety and depression: 37%

“This is a very large retrospective epidemiological body of evidence that corroborates this oral-systemic relationship,” Dr Richardson says.

Samuel Low, DDS, MS, MEd, Professor Emeritus at University of Florida, College of Dentistry, and the Chief Dental Officer and Vice President of Clinical and Dental Affairs for BIOLASE agrees, adding if it had only been a couple of articles that were not substantiated with other quality studies, the conversation might not be essential. However, numerous publications have found a relationship between inflammatory diseases of the body and periodontitis. Most recently, Dr Low says an October 2021 study in the Journal of Dental Research suggests obese patients with periodontal disease and COVID-19 are more likely to be admitted to the hospital and have higher mortality rates than other patients.

Dental professionals are poised to see indications of systemic conditions first, which can be crucial for early intervention. Hayley Johnson, RDH and Myofunctional Therapist, says that the mouth and nose are the gateways into the body, which means systemic conditions may present early with oral manifestations. Moreover, research shows that what is in the mouth doesn’t stay in the oral cavity.

“It has long been established that bacteria and other microbes associated with the oral cavity are active in other parts of the body and can play a role in bacterial endocarditis and other inflammatory diseases,” Johnson explains. “New studies show that the main pathogen in periodontal disease, P. gingivalis is has been associated with Alzheimer’s disease.”

Speaker and writer Richard Nagelberg, DDS, and Director of Medical Affairs for OraPharma, Inc., says the primary factor at play in the oral-systemic connection is inflammation. Reducing inflammation in the body is essential for patients’ health.

“The goal of dentistry really should be to keep the person as relatively free of inflammation as possible over their lifespan,” Dr Nagelberg says. “It is not to reduce pocket depth, bleeding on probing, swelling and all those things; that’s just a means to an end. By treating those things, you’re going to knock down the inflammation, which addresses their oral and overall health.”

Why Hygienists Are a Natural Fit for This Discussion

With such a strong association with all these serious medical conditions, the discussion about the oral-systemic link seems a natural fit for either a dentist or physician’s office. However, physicians tend to stick to the systemic side and dental professionals to the oral health side of the discussion. Moreover, patients expect it to be like this.

“The dentist’s office and the doctor’s office often have different roles in patients’ perception,”Johnson says. “There is a clear separation of oral considerations from the rest of overall health across much of the medical field and the general population. This separation leads to a perception that oral health is less important to overall well-being and therefore, oral health considerations are not prioritized in healthcare.”

Moreover, patients often separate their oral health from their physical well-being. Tom Viola, RPh, CCP, CDE, CPMP speaker, educator, and author on dental pharmacology, founded Pharmacology Declassified to help dental professionals understand the interplay between medications and diseases of the mouth and body. He says that most patients think of the mouth as distant from the body and don’t associate the oral cavity as an influence on systemic health.

It is vital to discuss the dental hygienist’s role when it comes to teaching patients about mouth-body connections.