Enamel Caries and Dentin Caries page 1 Perio Reports Vol. 26 No. 2 page 2 February 2014
in this section Enamel Caries and Dentin Caries by Trisha E. O Hehir, RDH, MS Hygienetown Editorial Director When I was a child, going to the dentist was a scary and often painful experience. It was never a question of did I have a cavity? It was always how many cavities did I have? Entering the dental hygiene field I soon learned that dental disease was completely preventable. The goal is preventing the very first lesion and keeping the mouth healthy for a lifetime is the expectation. This was a revelation to me as my entire family suffered from dental disease. Now, so many decades later, it s surprising to me that the very idea that dental disease is preventable is not widely known. It s actually a well-kept secret. Dentists and hygienists know intellectually that dental disease is preventable, but why doesn t the general public know this? I ve been having fun lately asking people I meet if they believe tooth decay is preventable. It is surprising to learn that most people believe that dental disease is inevitable. They have fillings, their parents had fillings and also lost teeth, so they fully expect their children to have the same. Statistics tell us that caries rates are higher among those at low socioeconomic levels. However, even when I ask highly educated, financially successful people, they don t believe dental disease is preventable. They believe that dental disease is inevitable. Ask your patients, family and friends if they believe tooth decay is inevitable. See what answers you get. Understanding the differences between caries in enamel and caries in dentin provide an opportunity to look at prevention today and make changes for the future. Perhaps one day in the not-too-distant future, everyone will know that dental disease is preventable and that new approaches and technologies are available today to make it a reality. n Inside This Issue 2 Perio Reports» 5 Profile in Oral Health: Understanding the Caries Process: Enamel Caries vs. Dentin Caries 1 FEBRUARY 2014» hygienetown.com
perio reports Brushing with a New vs. Old Manual Brush The general rule, although without scientific evidence, is to replace manual toothbrushes every two to three months. Some professionals suggest replacing the brush when the bristles become frayed, which can be a few weeks for some and a year for others, depending on their brushing force. Researchers at the Academic Centre for Dentistry in Perio Reports Vol. 26, No. 2 Perio Reports provides easy-to-read research summaries on topics of specific interest to clinicians. Perio Reports research summaries will be included in each issue to keep you on the cutting edge of dental hygiene science. Amsterdam compared new and used toothbrushes, with and without toothpaste, to determine plaque removal efficacy. A total of 45 subjects participated in the toothbrushing study. All subjects were non-dental students who routinely used a manual toothbrush. At baseline, each subject was given a standard, four-row, multi-tufted toothbrush and instructed to brush with it twice daily for three months. At that time they were scheduled to see the dental hygienist for professional toothbrushing and to measure toothbrush wear. The RDH brushed each quadrant with a different toothbrushing protocol: 1) new brush with toothpaste, 2) new brush without toothpaste, 3) old brush with toothpaste and 4) old brush without toothpaste. Pre- and post-brushing plaque scores were taken. Prior to the two-minute professional brushing, the brush was moistened with cold water and a timer set for 30 seconds for each quadrant. When comparing different toothbrushes, an absolute difference in plaque removal needs to reach 15 percent. In this study, the absolute difference was only five percent. There was no real difference between old and new toothbrushes. Brushes with little wear outperformed new brushes while worn toothbrushes were less effective compared to new brushes. Toothpaste provided no benefit for plaque removal. Clinical Implications: It s not the age of the toothbrush, but the wear of the bristles that signals time for replacement. n www.hygienetown.com Rosema, N., et al: Plaque-Removing Efficacy of New and Used Manual Toothbrushes - A Professional Brushing Study. Int J Dent Hygiene 11:237-243, 2013. Reducing Patient Fear with a Direct Approach About half of the adult population suffers from some degree of dental fear, making it one of the most prevalent fears. In dentistry, there are three responses to a sense of danger: fear, phobia and anxiety. Dental fear is a reaction to a known danger, provoking the fight or flight response, almost always caused by a previous bad experience. Dental phobia is a response similar to dental fear, only much more intense and debilitating. Dental anxiety is a reaction to an unknown or not immediately present danger. It is often a consequence of receiving negative information without personal experience. The psychological approach of direct interaction was used in an attempt to reduce patients dental fear associated with a dental hygiene visit. A pre- and post-treatment questionnaire was given to patients who showed any level of dental fear. Using a zero to 10 scale, patients were asked how they would rate: 1) fear of your last dental hygiene visit? 2) avoidance of today s visit? 3) confidence in your last RDH? The RDH explained procedures, asked what each patient liked and didn t and showed them what she was doing. Posttreatment questions asked how the patient would rate: 1) fear of today s visit 2) likelihood of avoiding their next dental hygiene visit and 3) confidence in the RDH today. No subjects reported more fear after the visit and 83 percent reported decreased fear after the visit. Modern dentistry should not be a fear-inducing experience. Patients should be treated with empathy and dignity. Clinical Implications: Dental fear can be reduced with a direct approach that takes into consideration the baseline fear of the patient. n Roubalova, L.A.: Can a Patient s Fear be Reduced Using the Psychological Approach of Direct Interaction? OHU Action Research 1A-13, 2013. continued on page 3 hygienetown.com «FEBRUARY 2014 2
perio reports continued from page 2 The Feeling of Xerostomia vs. Clinical Hyposalivation Hyposalivation is the objective measure of reduced saliva. Xerostomia is the subjective feeling of dry mouth. Increasing numbers of medications produce hyposalivation as a side effect, leading to higher levels of dry mouth. The Xerostomia Screening Questionnaire described by Navazesh was designed to identify patients with dry mouth, by assessing the most common, subjective complaints related to xerostomia. The Challacombe Scale of Oral Dryness uses clinical images of various stages of oral dryness to identify objective signs of hyposalivation. Some individuals with salivary gland hypofunction are not aware of a reduction in the amount of saliva they feel in their mouths. A project was designed to compare objective clinical oral dryness scores with subjective responses to the xerostomia screening questionnaire. Twenty patients with clinical signs of oral dryness were asked to complete the Xerostomia Screening Questionnaire. The dental hygienist completed the Challacombe Scale for each patient. According to the Challacombe Scale parameters, 55 percent of the participants had signs of moderate oral dryness and 45 percent had mild oral dryness. Seventy percent of the questionnaire respondents reported too little saliva. Although 100 percent of the participants displayed clinical signs of oral dryness, 30 percent denied experiencing any xerostomia symptoms. Further research is needed to discover why people with reduced salivation don t always feel the symptoms. It might also be that the questionnaire did not contain questions that effectively reflected oral dryness symptoms. Screening should include both objective and subjective aspects of xerostomia. Clinical Implications: Patients with clinical signs of dry mouth may not actually be aware of a reduction in saliva. n Douglas, L.M.: Investigating the Relationship between Clinical Oral Dryness Scores and Xerostomia Screening Questionnaire Responses. OHU Action Research 11A-12, 2013. Video Chats Improve Children s Oral Hygiene Habits Twice yearly dental hygiene visits do not provide adequate coaching to help children and parents stay motivated to follow effective daily oral hygiene. The introduction of new technology provides options for following up with patients between visits. Weekly visits via Skype or FaceTime may provide an option for video coaching to improve oral hygiene habits. For this project, five children (four boys and one girl) and their parents were recruited. The children all had high plaque levels, high decay rate and lacked motivation. Their ages ranged from six to 13 years old. Thorough oral hygiene instructions were given at the clinical appointment, including brushing, interdental cleaning and diet suggestions. Permission was granted from each parent to contact their child for a follow-up video chat. Parents were urged to participate in the video chat as well. During each video chat, the children demonstrated how they brushed their teeth and how they cleaned between their teeth. If technique changes were needed, the RDH would use a model to show proper technique. Diet was also discussed, as well as methods that work best for each individual patient and what goals they would strive to meet before the next visit. The parents that did participate during each of the visits followed close along and were involved in the goal-setting process. Based on the results of a questionnaire for parents, the video chats had a positive impact. Each parent reported improvement in motivation and technique. Four out of five reported their child was brushing twice daily. Parents also reported taking a more active role in their child s oral health. All parents and children would like to continue with meetings via video chat. Clinical Implications: Consider following up with patients using video chat technology. n Richey, C.: Using Technology to Improve Oral Hygiene. OHU Action Research 5A- 13, 2013. 3 FEBRUARY 2014» hygienetown.com
perio reports Are Hygienists as Effective as They Think They are with Oral Hygiene Instructions? The role of the dental hygienist is to instill the need, desire and ability for his or her patients to achieve optimum oral health. Too often the patient is not motivated to take an active role in their oral health. They aren t interested in what the hygienist is saying and unwilling to comply with oral hygiene instructions. They may not see the value in what they are being told. The result is ongoing dental disease when it could be prevented. The purpose of this study was to determine if patients correctly understood the oral hygiene instructions provided by their dental hygienist and to see if RDHs feel they are giving patients individualize instructions. A seven-question electronic survey was sent to 30 hygienists about recommendation and customization of oral hygiene instructions. A similar seven-question electronic survey was sent to 30 non-dental professionals. These were not the patients of the RDHs questioned, but represent an educated patient pool. Of the RDHs, 57 percent responded. When asked if they offered alternatives to dental floss to clean interproximally, 100 percent answered affirmatively. Of the non-dental professionals, 46 percent responded to the survey. When asked a similar question about whether their RDH offered an alternative to flossing, only 29 percent answered yes. These findings reflect the disconnect between what RDHs believe they are conveying to their patients and what the patients actually hear. Based on these findings, communication and motivational interviewing should include the patient in their oral health-care decisions and oral hygiene care routines. Clinical Implications: Patients do not always hear and understand what RDHs believe they provide in their instructions to patients. n Byrne, C.: Can Patients Achieve Better Oral Health Through Motivational Interviewing. OHU Action Research 5A-13, 2013. What Does it Take for Patients to Change Behavior? Dental health-care providers expend significant effort to help each patient achieve better oral health through prevention. The problem is many patients are not very good at complying with the recommendations offered to them. They frequently return with the same problems and no real change in their oral hygiene. The purpose of this study was to determine if a simple follow-up contact would impact behavior change in a group of 18 patients. For each patient, a specific oral hygiene recommendation was given, based on their individual needs. Included were flossing, antibacterial rinses, interdental brushes and picks. Contact was made with the patients one week after their routine dental hygiene appointment. They were contacted via text messaging or e-mail, based on their preference. Nineteen patients agreed to be part of this study and they were sent a short three-question survey. The patients were asked if they tried the specifically recommended item, if they liked using it, why or why not. The response rate was 50 percent. Those who responded did state that they tried the recommended product, but only 33 percent of the patients felt they would continue to use the recommended product. This action research project showed that in a group of willing participants, only one-third changed their behavior. The author concluded from this study that follow-up contact alone is not an effective method to change behavior and does not increase compliance with oral health recommendations. Clinical Implications: More is needed than one clinical interaction and a single follow-up contact to ensure behavior change in patients when new oral hygiene instructions are given. n Huber, M.: Does Follow-up Contact Increase Patient Compliance with Oral Hygiene Recommendations? OHU Action Research 5A-13, 2013. hygienetown.com «FEBRUARY 2014 4
profile in oral health 5 FEBRUARY 2014» hygienetown.com
profile in oral health Enamel Caries vs. Dentin Cariesby Trisha E. O Hehir, RDH, MS Introduction Enamel is the hardest substance in the human body. It is in a constant state of flux, going back and forth from demineralization to remineralization. Every time there is a drop in the oral ph below 5.5, enamel demineralizes. Drinking orange juice, wine or soda will demineralize the enamel. Remineralization then occurs with the help of salivary minerals and buffering agents. This natural ebb and flow can be disrupted by continuous exposure to acid, usually in areas protected from the remineralizing benefits of saliva. When bacterial biofilm covers pits and fissures and interproximal sites, the acid is held against the tooth surface with no remineralization possible. The demineralization affects enamel, eventually visible as white spot lesions. The next step is cavitation and eventually the demineralization moves into the dentin. At this point, the process changes. Bacteria-produced acids begin the demineralization process in the dentin, and then endogenous, zinc-dependent proteases destroy the dentin. The bacteria are responsible for the initial demineralization and destruction of enamel, but then substances within the body that are often beneficial become destructive to the dentin. This two-phase destruction of tooth structure requires a variety of preventive approaches. Traditionally, the focus was to protect the enamel with fluoride and by disrupting bacterial biofilm formation and reducing the consumption of fermentable carbohydrates. Based on new scientific findings, additional strategies are needed to inhibit the destructive actions of proteases, specifically the family of Matrix metalloproteinases (MMPs). Better understanding the carious process from enamel through dentin will provide new options for preventing and reversing carious lesions. Caries in Enamel Plaque biofilm is composed of a multitude of bacteria including Streptococcus, Lactobacillus and Actinomyces species. Oral bacteria convert carbohydrate foods and drinks in the mouth for their own energy through a process of fermentation. Lactic acid is a byproduct of this fermentation process and with a ph below 4 is capable of demineralizing enamel. This acidification of the biofilm causes demineralization of enamel. The acidification of the biofilm provides an environment conducive to the proliferation of acidogenic and aciduric bacteria, those that prefer a low ph environment and those that produce lactic acid. As long as the environment continues with a low ph, enamel demineralization will continue. No disruption of the biofilm and continued acid production will lead to more demineralization and eventual cavitation. A constant source of fermentable carbohydrates feeds these acid-producing bacteria. Although often referred to as sugar bugs, it s not just sucrose or table sugar that leads to acid production. Hydrolyzed starches can be fermented to produce lactic acid as well. These starches are long chain sugars that contribute to acid production. Potato chips, pasta, bread and other starches will all provide the nutrients necessary to continue the caries process. Although sucrose is the primary factor, hydrolyzed starches are also considered fermentable carbohydrates. Caries in Dentin The carious process within dentin differs from that in enamel. Dentin is less mineralized, containing 20 percent organic material compared to only one percent in enamel. The bacteria-produced acids that dissolve enamel will also dissolve the dentin mineral, uncovering the organic dentin extracellular matrix (ECM). Proteases are then responsible for degradation of ECM, allowing the movement of bacteria toward the pulp. The tubular nature of dentin enhances this movement of bacteria. It was long thought that the proteases degrading the ECM were produced by the bacteria, but recent findings suggest that bacterial proteases cannot withstand the drop in ph that often reaches 4.3. New theory suggests that host-derived, zinc-dependent proteases, specifically Matrix metalloproteinases (MMPs) found within dentin and saliva, are responsible for the degradation of dentin. MMPs are involved in both normal and destructive actions throughout the body. MMPs consist of a family of endogenous proteolytic enzymes. Some are associated with dentogenesis and others are capable of degrading dentin. Active MMPs have been found in demineralized dentin, suggesting they can disorganize and degrade the dentin matrix. MMPs require metal ions, specifically zinc, for activation. Strangely, the MMPs must be activated, often by acids, but then require a neutral ph to destroy the matrix components. The bacteria-produced acids can activate the MMPs and it s thought that salivary buffers then allow dentin destruction by the MMPs. Examination of extracted, carious teeth shows a gradual change in the gelatinous texture of the dentin. The continuum includes a superficial soft carious lesion, an inner soft carious lesion, affected dentin and sound dentin. The Caries/Diet Connection Today s diet no longer includes three meals and a snack after school, as was the trend years ago. Today, fermentable carbohydrates are consumed continuously throughout the day and into the evening. Snacks and fizzy drinks are readily available all day long. This contributes to the ecological plaque hypothesis introduced by Drs. Takahashi and Nyvad that the ph of the plaque biofilm determines disease activity. High intake of fer- continued on page 7 hygienetown.com «FEBRUARY 2014 6
profile in oral health continued from page 6 mentable carbohydrates will favor acid production and proliferation of acid-producing oral bacteria. Changing the diet by reducing the intake of fermentable carbohydrates can elevate the ph, shifting the ecology of the biofilm to one more conducive to health. Introducing oral probiotics may shift the balance of bacteria in the mouth to those preferring a higher ph. Competition between established acid-producing bacteria and specific species contained in oral probiotics leads to metabolism of lactic acid into hydrogen peroxide, which will inhibit S mutan growth. Xylitol also interferes with the sucrose glycolosis. Xylitol is a five-carbon molecule, not six like sucrose. The smaller molecular size allows xylitol to pass through the outer cell wall of the bacteria easily, but it is not the right molecular structure to be used by the bacteria to produce energy. The bacteria must then use its own energy to pump the xylitol molecule out via a membrane pump. This process expends energy without providing an energy source for the bacteria. Xylitol also blocks the communication between bacteria, interfering with quorum sensing, a key function in the formation and maintenance of biofilm structure. Without mechanical disruption of bacterial biofilm, three to five exposures to xylitol daily will reduce bacterial biofilm levels by approximately 50 percent. Preventive Strategies Now and in the Future Until now, caries prevention has focused on enamel caries, with no specific approaches to prevent dentinal caries. Control of diet, adequate biofilm removal and fluoride exposure are components of the current approach to caries prevention. MMP inhibitors may be the next level of prevention focused on prevention of dentin demineralization. Research is now being done to determine if the use of chemical or natural MMP inhibitors can control caries progression within dentin. The tetracycline family of antibiotics can inhibit MMPs, separate from their antimicrobial properties. Zoledronate, a third generation bisphosphonate, is also a potent MMP inhibitor. However, these drugs are used systemically and a better choice will be a topical product. Chlorhexidine as well as Ethylenediaminetetraacetic acid (EDTA) will impair MMP activity and can be used topically. Other potent MMP inhibitors come from natural sources, including green tea polyphenols and grape seed extract. Grape seed extract suppresses lipopolysaccharide-induced MMP secretion by macrophages. Grape seed extract was shown in laboratory studies to both inhibit demineralization and promote remineralization of artificial root caries lesions. Both chemical and natural ingredients can be incorporated into oral rinse and toothpaste products in the future. Conclusion The caries process involves destruction of both enamel and dentin, with a combination of damaging actions. Prevention and remineralization are two critical approaches to address with new scientific knowledge and modern technologies. Prevention and remineralization of early lesions are possible using both traditional and contemporary approaches. n To comment on this article, visit Dentaltown.com/magazine.aspx. Products Services Extra Advertisement Introducing the Contact Genie Uses the patient s own biting force to easily open up blocked or tight contacts. Just place the Contact Genie into the contact area and use thumb pressure or have the patient bite down while gently rocking the Contact Genie up and down. Contacts are easily made floss-able saving valuable chair time. An indispensible tool for your dental toolbox. Order now at Angiesdental.com or call 855-655-4290. PinkBand PinkBand is a rubberized silicone coated matrix band effective in improved moisture control over standard and sectional bands*. Contamination is the number one cause of bond strength reduction in adhesive properties of composite material, causing recurrent decay and post-operative sensitivity. PinkBand s innovative matrix band improves moisture control and reduces contamination. PinkBand saves time, frustration and money. PinkBand is available in universal, pedo and subgingival sizes in both regular 0.0015 and ultra-thin 0.001. Call 847-260-8330 or visit www.pinkband.org *Reference The Dental Advisor, Vol 30, Issue 08, October 2013. 7 FEBRUARY 2014» hygienetown.com