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White Paper: Innovation in Early-Stage Caries Detection

INNOVATION IN EARLY-STAGE CARIES DETECTION:

Leveraging Localized pH Sensing To Detect Active Tooth Demineralization

Introduction:

Caries is the most prevalent noncommunicable chronic disease, affecting 90% of the population in the United States (Health 2021). Caries has an increased impact on low-income communities, and children. Dental caries poses significant economic and societal burdens, giving rise to complications such as infection, discomfort, tooth loss, psychological impact, and even death (Gupta et al. 2018; Health 2021).

Dental caries result from tooth-adherent cariogenic bacteria which metabolize sugars to produce acid (Abou Neel et al. 2016; Bowen 2013; Stephan 1944). The lactic acid that is secreted by bacteria drops the pH on the tooth surface. In 1944 Stephan et al. showed a direct association between plaque pH levels and caries (Stephan 1944). They showed that following activation of the cariogenic bacteria with sucrose there is a drop in plaque pH specifically in patients with active caries. It was also noted that a specific pH level of 5.5 switches on the demineralization process of hydroxyapatite and enamel (Li et al. 2014):

Once that pH drops below 5.5, the active demineralization process of the tooth begins. This process undermines the hydroxyapatite crystals’ structure and eventually leads to destruction of the tooth composition and a dental cavity (Fontana et al. 2010; Foros et al. 2021; Li et al. 2014; Urquhart et al. 2019).

Stephan et al. showed that only in patients with active caries the localized plaque pH dropped below the threshold of 5.5 following a sucrose activation step (Figure 1). This means that for patients with no caries activity the sucrose challenge will not cause a drop in pH that is below the demineralization threshold of 5.5.

 


Caries diagnostics is challenging on visible surfaces and even more so in interproximal surfaces/spaces. Here, we report on the very first, low-cost, localized pH-sensing Toothpick that can help detect active demineralization in interproximal surfaces /spaces within 10 seconds.  By design, the CaviSense Toothpick can be used by the entire clinical team and applied at different touchpoints along the patient journey (eg, in the chair; in the waiting room before the chair; and even as part of an on-going, monitoring plan).

Based on our Harvard/Tufts patented technology, the CaviSense Toothpick can locally detect tooth surfaces with pH <5.5 (Matzeu et al. 2021). The CaviSense Toothpick tip changes color within 10 seconds of contacting an actively demineralizing tooth surface. The CaviSense Toothpick can be inserted between teeth as well as into narrow fissures or pits to sense a cavity-conductive environment. The tip of the device changes color in a binary manner from purple to yellow at a pH < 5.5.

Study Objective:

In this study, pediatric dental offices used CaviSense Toothpicks to test the product ease of use and agreement with dental diagnosis of caries.

Materials and methods:

The study was approved by WIRB protocol #20235520. Five pediatric dental offices were selected:

  1. Gila C. Dorostkar DDS, Pediatric Dentistry, CA, USA
  2. Smiles4Children, MD, USA
  3. Naples Pediatric Dentistry, FL, USA
  4. Keep Smiling Kids, OH, USA
  5. Pediatric Dentistry + Orthodontics of Concord and Marlboro, MA, USA

 

Dentists were given a supply of CaviSense Toothpicks for 2 weeks and access to the CaviSense Pro app. Dentists were instructed to use CaviSense Toothpicks at will and where they thought appropriate. Prior to use, a product training session was given by CaviSense. Via the CaviSense Pro app, the dentist and their clinical teams recorded the tooth surfaces tested, the CaviSense Toothpick test results and alignment with their diagnosis based on visual examinations done prior to the test.

For statistical analysis, we used dentist diagnosis as the truth in terms of diagnosis and calculated the agreement percentage between the dentist diagnosis and CaviSense Toothpick Pro result.

Device:

 Figure 2.  CaviSense Toothpick

 

CaviSense developed a unique proprietary colorimetric, pH-sensing material initially discovered at Harvard and Tufts (Matzeu et al. 2021). The CaviSense Toothpick has an active, colorimetric tip that once contacting a tooth surface will sense the pH within 10 seconds (Figure 2).

The CaviSense Toothpick tip will change its color from purple to yellow once sensing a pH<5.5. The reference window (Figure 2) of the Toothpick always remains at the original purple color for easy comparison and validation of color change by the clinician (Figure 2 and 3). Prior to the study, the CaviSense Toothpick was found to be 98% accurate in pH detection in laboratory tests. 

 

Figure 3.  CaviSense Toothpick, positive and negative readings.  Note the color changing colorimetric tip. Also note the reference window color always remains purple. 

 

The Toothpick is single use and can be inserted in interproximal spaces as well as into pits and fissures (Figure 4).

 

Figure 4: CaviSense Toothpick, inserted in an interproximal space, the sensing tip is facing the measured surface, in this case the Distal surface of the lower right E.

 

The CaviSense Toothpick is accompanied by a mobile application (the CaviSense Pro app) with features including toothpick tip magnification for better capturing of results in addition to functionalities facilitating data transfer to practice records and treatment plan follow ups.

Use cases:

Dentists were instructed to use the CaviSense Toothpicks as they deemed appropriate in their clinical work related to the diagnosing and monitoring caries in addition to patient communication.

Common use cases examples were:

  • When x-rays could not be obtained due to gag reflex issues, fearful or apprehensive patients, parents' resistance to radiation or other reasons;
  • When x-rays were not clear;
  • To check the active/arrested status of a demineralized lesion on x-rays;
  • When investigating early-stage cavities not visible on x-rays;
  • To verify secondary cavities – open margins in restorations or crowns
  • To assess patients with braces - evaluating potential active demineralization interproximally or around brackets
  • Monitoring remineralization treatments (eg, SDF).

 

Workflow:

The CaviSense Toothpick was used on new patients as well as established patients prior to any cleaning or dental procedures.

Instructions were:

  1. Provide bacteria activation tablet (included in the CaviSense Toothpick kit). This step is required to activate the acid producing bacteria to their maximal acid production state. This baseline-generating step negates fluctuations attributable to salivary production or prior food/drink consumption.
  2. Insert the Toothpick device into/on the selected tooth surface and maintain contact for 10 seconds.
  3. Withdraw the Toothpick device and record the result in addition to the dentist diagnosis via the CaviSense Pro app.

 

Results:

Overall, 23 pediatric dentists in five pediatric clinics utilized the CaviSense Toothpick to test 264 teeth of patients aged 3-18.  Dentists were instructed to use the CaviSense Toothpick on any surface of the tooth and could delegate the use to any staff member they trained.

The device was evaluated as easy to use by dentists as well as dental hygienists and assistants. No adverse events were reported, and patients did not report any discomfort while using the device. The CaviSense Toothpick was well received both by parents and patients with an acceptance rate slightly above 98%. Five parents declined to be part of the study but did not raise concerns about the device itself.

The clinicians developed confidence and trust in the Toothpick results after using the device in many situations.  Most clinicians began their testing with cases that were obviously positive or negative to see if there was agreement with their diagnosis.  After gaining confidence they began to use the Toothpicks in less obvious cases and eventually in cases where they had the greatest need for the Toothpick information.

  

  

Overall, the agreement between the CaviSense Toothpick results and dentist diagnoses was 72% (ranging between 66-81%) considering all tooth surfaces as a pool. The CaviSense Toothpick was found to be 98% accurate in pH detection in laboratory tests. The high accuracy in lab setting was reflected by the high confidence dentists felt while using the Toothpick. As such, in instances of disagreement between dentist diagnosis and CaviSense Toothpick results, we saw two decision making patterns:

  1. In cases where the dentist diagnosed a negative result and the CaviSense Toothpick yielded a positive result (28 teeth, 10%), dentists attributed the lack of agreement to the ability of the Cavisense Toothpick to detect early-stage tooth demineralization. In these instances, dentists implemented a clinical treatment based on the CaviSense Toothpick result. As part of the test, dentists also tested teeth surfaces with excessive plaque and reported that the CaviSense Toothpick yielded a positive result only when the underneath surface was cavitated/ undergoing demineralization.
  2. In cases where the dentist diagnosed a cavity and the CaviSense toothpick showed negative result (41 teeth, 15%), dentists decided on treatment modalities based on their initial positive diagnosis and attributed the discrepancy to reduced salivary availability on the measured surface or other technical issues.

 

Discussion:

Dental caries is a chronic infectious disease associated with bacterial activity. When diagnosed early, a carious lesion can be remineralized.  However, despite the many options for remineralization, the detection of early-stage cavities is still a challenge (Chan et al. 2023; Cummins 2013; Diniz et al. 2012; Foros et al. 2021; Li et al. 2014; Lino et al. 2015; Souza et al. 2018; Urquhart et al. 2019). The lack of clinical, diagnostic tools impedes the utilization of such remineralization techniques and prevents significant improvement of oral health and potentially overall health. The CaviSense Toothpick is easy to use and does not require any sophisticated or specialized light source or cleaning after use. It also does not require any ionizing radiation and thus can be utilized at any point in time and with any frequency.

The enhanced assessment capabilities afforded by CaviSense technology can help clinicians deliver superior oral health outcomes, better patient experiences and improved profitability. 

In private practice settings, the CaviSense Toothpick helps clinicians:

  • Detect high-caries-risk tooth surfaces on patients where clear x-rays are unavailable or difficult to obtain due to patient issues;
  • Better identify and monitor patients requiring more frequent office visits to better accompany the progression of a patient’s high-risk surfaces;
  • Identify more high-caries-risk tooth surfaces with active demineralization that may not appear on x-rays and that should be addressed immediately;
  • Increase the acceptance rate of recommended treatment plans (including x-rays);
  • Reinforce to patients the prevention-focus approach of the clinical team.

In public health settings, the CaviSense Toothpick helps clinicians:

  • Increase annual dental visit rates;
  • Better identify high-caries-risk tooth surfaces that require immediate, preventive attention that can help avoid more traumatic / more costly restorative procedures;
  • Extend the impact of mobile dentistry and community health outreach programs.

Many high caries risk populations suffer from low accessibility to dental care due to financial limitations, commuting distance, etc. An efficient, early-stage caries detection and risk assessment tool that requires minimal training could significantly improve accessibility and treatment outcomes. Current solutions for early-stage caries detection are predominately based on technologies such as infrared, fluorescence, electrical impedance or dye-based visualization techniques.  Unfortunately, they are either expensive or complicated to operate; especially in a busy office setting or in a remote location with less trained personnel (Chan et al. 2023; Diniz et al. 2012; Foros et al. 2021; Lino et al. 2015; Souza et al. 2018). The CaviSense Toothpick is small, lightweight, low cost and uniquely designed to assist in early-stage-caries risk initiatives wherever the patient is.

Dentists found CaviSense Toothpick reliable and providing additional information and certainty in a questionable diagnosis. In cases where the Toothpick turned yellow in an area that was questionable or considered as negative for caries (10%), dentists followed the CaviSense Toothpick result. In cases where a cavity was perceived but the Toothpick showed a negative result (15%), most dentist attributed the gap as technique related.

In this study we focused on agreement with dentist diagnosis since x-rays which is the gold standard in caries diagnostics is limited in its specificity and sensitivity especially in early-stage caries with sensitivity as low as 15% (Chan et al. 2023). Future studies could focus on defining the specificity and sensitivity of the CaviSense Toothpick specifically looking at early-stage caries.

Conclusions:

  • Easy to use - The Cavisense Toothpick device was perceived by clinicians and the clinical teams to be effective, easy to use and easy to incorporate into their current work flow and of significant value in helping diagnosis of early-stage-caries; especially in hard-to-reach, interproximal spaces whenever x-rays were difficult to obtain.
  • For both Detection and Monitoring - The clinicians agreed that the top use cases for the Cavisense Toothpick we subdivided into detection and monitoring instances.
  • When X-rays are difficult to obtain or inconclusive - Detection was extremely useful in the 4-6 year old age group when getting x-rays was difficult. Other categories with similar characteristics are special needs cases where obtaining high quality x-rays is a challenge.
  • When X-rays are not recommended – in young kids, 2-3 years old, or when x-rays were recently taken.
  • For orthodontics patients - Monitoring was found useful in patients with braces as well as with those undergoing remineralization treatments.
  • For Increased treatment plan acceptance – The Cavisense Toothpick was also found to be a motivational communication tool with parents. When the Toothpick tip turned yellow, clinicians took advantage of the opportunity to educate the patients and parents about pH and motivated parents to accept treatment recommendations: including; but not limited to preventive measures such as the application of SDF or other remineralization agents; more frequent visits; the taking of x-rays; etc.
  • Emotional benefit for children – early caries detection leads to quicker, less invasive treatments that generate less stress on the child and the overall household.

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