Efficacy of seventh generation bonding agents as desensitizers in patients with dentin hypersensitivity: a randomized clinical trial

Prior to the commencement of the main study, a rigorous examiner calibration process was conducted to ensure consistency and reliability in the application of the Discomfort Interval Scale (DIS) and the Schiff Cold Air Sensitivity Scale. The Department of Periodontology at Dow University of Health Sciences facilitated this training and calibration over five days, involving 20 participants distinct from those in the main study.

Clinical examiners 1 and 2, who were designated for the study, participated in the calibration process. They independently assessed the pain responses of the participants using both the DIS and Schiff scale. To establish intra-examiner reliability, each examiner reassessed the same participants after a suitable interval without referencing their initial scores, ensuring a blind re-evaluation.

The calibration results demonstrated high intra-examiner reliability for both examiners on the DIS, with examiner 1 achieving a reliability score of 0.88 and examiner 2 achieving 0.90. Similarly, for the Schiff scale, Examiner 1, and Examiner 2 reported reliability scores of 0.82 and 0.88, respectively, indicating strong consistency in their assessments.

Inter-examiner reliability was also calculated to determine the degree of agreement between the two examiners. For the DIS, the inter-examiner reliability was 0.75, while the Schiff scale was 0.80. These results suggest a substantial level of agreement and confirm the effectiveness of the calibration process.

Through this comprehensive calibration, we ensured that the examiners were well-aligned in their understanding and application of the scales, thus bolstering the validity of the subsequent measurements in our study.

The collected data were processed and analyzed using SPSS software (version 22). For categorical variables, such as brushing habits, brushing frequency, gender, frequency of sensitivity, and types of sensitivity, frequencies and percentages were calculated. The mean and standard deviation were determined by age.

Cross-tabulation offered in-depth insight into the baseline discomfort interval scale scores across the three groups before applying the desensitizing material. This approach also facilitated a better understanding of the distribution of Schiff scores among the groups in response to various stimuli.

The normality of the DIS and Schiff scores was assessed using both the Kolmogorov-Smirnov Test and the Shapiro-Wilk Test. For every time interval (DIS_before, DIS_immediately, DIS_1wk, and DIS_1mnth), the tests yielded significance values (p-values) less than 0.05 (specifically, 0.000), indicating a significant deviation from a normal distribution. Similarly, for the Schiff scores at all time intervals (Schiff_before, Schiff_immediate, Schiff_1wk, and Schiff_1month), the p-values were consistently less than 0.05, signaling a marked departure from a normal distribution.

To discern differences in both the DIS and Schiff scores across the three desensitizing materials at varied time intervals, the Kruskal-Walli’s test was deployed. Furthermore, to evaluate the changes in the Discomfort Interval Scale (DIS) and Schiff scores pre- and post-application of each desensitizing material (Single Bond Universal, Xeno V+, and Bifluorid 12) at the designated time points (before, immediately, one-week post-application, and one-month post-application), the Wilcoxon Signed-Rank Test was utilized. The threshold for statistical significance was established at less than 0.05.

In summary, all three desensitizing materials (Single Bond Universal, Xeno V+, and Bifluorid 12) significantly reduced discomfort and sensitivity compared to baseline, indicating their effectiveness in managing dental sensitivity. No material showed superiority over others at one month, suggesting their comparable benefits. Thus, the use of these materials can be deemed beneficial for addressing dental sensitivity, irrespective of the specific product chosen.

The present study provides insightful findings on dental hygiene practices, tooth sensitivity patterns, and the efficacy of different desensitizing materials over time. The present study tested the efficacy of seventh-generation dentin bonding agents as desensitizers, taking fluoride varnish as the control group in patients with dentin hypersensitivity.

The mean age reported in the present study was 27.75 ± 7.43, indicating a relatively young adult cohort. This demographic characteristic is consistent with the target population of many oral health studies focused on individuals aged 18–35 years to assess oral health behaviors [18‐20]. Graf et al., in their study, stated that sensitivity is commonly seen in people 20 to 40 years of age [21, 22]. Many studies described different prevalent age groups of dentin hypersensitivity; Vijaya reported 18–27 years [23], Amarasena recorded 30–49 years [24], Bahsi documented 40–49 years [25], and Rees J published 40–50 years [26].

The gender distribution, with more female participants, aligns with research suggesting that women are more likely to report tooth sensitivity, potentially due to differences in perception or reporting behaviors [1]. In the present study, most patients were female, constituting 65.7%, suggesting DH is more commonly observed in females. Feng and companions reported a higher prevalence of DH in females, corresponding to the results of the present study [27]. In Northwest America, a study documented a higher frequency of DH in females, corroborating this study [28]. A study conducted in Australia also found that DH most commonly affects females [24]. Bahsi et al., working on the prevalence of DH [25] and another study on cervical dentin hypersensitivity [29], recorded DH more frequently in females, just like the present study. However, few studies documented a higher prevalence of dentin hypersensitivity among males, contrary to the present study’s findings [30].

Regarding dental hygiene, 96.2% of participants used a toothbrush, while 3.8% used Miswak. This aligns with global oral hygiene practices, where using a toothbrush is predominant. However, the use of Miswak is culturally specific. It has been reported to have similar efficacy to toothbrushing in plaque reduction, as noted in the study by Al-Otaibi et al. (2003) [31].

The frequency of brushing habits revealed that 52.4% of participants brushed once and 44.8% twice daily. It is slightly less than what dental associations recommend globally, which recommends brushing twice a day [32]. It is worth comparing these findings with those of Folayan et al. (2020), who reported a higher prevalence of twice-daily brushing in a similar age group [33]. This variance in dental hygiene habits could be influenced by cultural, educational, or economic factors.

This study reported that cold stimuli were the most common cause of sensitivity. In the present study, almost 51% of patients were sensitive to cold stimuli; the result parallels the study conducted in Karachi in 2016, reporting 71% sensitivity to cold [20]. This observation is corroborated by other studies, such as Rees and Addy (2002), who found that cold stimuli are the most frequently reported trigger for dentinal hypersensitivity [34, 35].

In the present study, lower incisors were the most commonly affected teeth with dentin hypersensitivity, followed by upper incisors. Gingival recession is one of the reasons for the frequent involvement of lower incisors. Teeth involved in hypersensitivity showed much variability in different parts of the world. A study on the prevalence of dentin hypersensitivity in Hong Kong reported lower incisors as the most sensitive teeth [26]. Another study observing the frequency of DH in Pakistan documented mandibular incisors as the most commonly involved teeth in hypersensitivity [20]. Frequent involvement of lower incisors was also reported in Indian Rural Punjab [35]. The results of all these studies are in agreement with the findings of the present study.

In contrast to the results of the present study, a pilot study on CDS reported hypersensitivity in molars. A cross-sectional study on buccal cervical sensitivity in the United Kingdom reported molars and premolars as the most commonly affected teeth, and they also reported lower central incisors to be the least sensitive teeth [36]. Multiple researches also reported sensitivity in bicuspids [5, 36].

All the materials (Single Bond Universal by 3 M ESPE, Xeno-V + by Dentsply, and Bifluorid 12 by Voco) used in the present randomized clinical trial significantly reduced dentin hypersensitivity immediately after application of the desensitizing material after 01 week and over 01 month, proving seventh generation dentin bonding agents as a successful treatment option for treating dentin hypersensitivity.

Bifluorid 12, a fluoride varnish, contains calcium and sodium fluoride. It acts by forming precipitates of Calcium Fluoride within orifices of tubules and on the tooth surface, occluding the patent tubules by crystallizing Sodium Fluoride [37]. TM Silva et al. evaluated the efficacy of desensitizing agents for the relief of dentin hypersensitivity using a split-mouth model; they declared a significant reduction in hypersensitivity after application of Bifluorid 12, for tactile and evaporative stimulus for a period of three and four weeks, respectively [38], corresponding to the results of the present study. An in vivo study conducted in 2010 tested the efficacy of Bifluorid 12 and found it useful for thermal dentin hypersensitivity for 01 month, just like the present study [39], but could not maintain it for mechanical dentin hypersensitivity for 01 month.

Another randomized controlled trial comparing different desensitizing agents reported a significant reduction in hypersensitivity immediately post-treatment and 02 months post-treatment using fluoride varnish and potassium salt solution, congruent with our findings [40]. Nardi et al. also declared a significant reduction in sensitivity after 30 and 90 days of application of 02 different varnishes [41].

Loveren et al., in their study, indicated the use of DBA as an in-office professional treatment option for treating dentin hypersensitivity [42]. A 03 months follow-up study found no difference while checking the effect of one bottle adhesives in treating hypersensitivity with or without acid etching [43]. In a comparative study of different generations of DBA, the fifth generation was declared more efficient in reducing DH [44]. They also reported that the efficiency of dentin bonding agents to reduce hypersensitivity decreases with time. The study on tooth cervical hypersensitivity tested the effectiveness of the desensitizing ability of glutaraldehyde-based HEMA and one bottle bonding agent and found no differences after 08 weeks follow-up. However, after 09 months, Gluma showed less hypersensitivity and was reported to be more durable [45]. While comparing the effectiveness of one bottle of self-etching adhesive, dentin desensitizer and a combination of both for treating dentin hypersensitivity, Shruti et al. reported significant reduction in all 03 groups for 06 weeks. However, dentin desensitizer and a combination of adhesive with desensitizer showed greater reduction than one bottle of self-etching adhesive [46].

A clinical trial evaluated the efficacy of self-etch adhesives on hypersensitivity after periodontal surgery and found its use beneficial [47]. A randomized clinical trial evaluating dentin desensitizers reported that all the materials used in the study significantly reduced hypersensitivity immediately, and adhesives relieved the pain over 01 month similar to the results of this study [39].

Discrepancies in the findings of various studies could be attributed to differences in the study populations, methodologies, and local practices or perceptions. The contrasting results regarding the most affected teeth and long-term efficacy of treatments underline the complexity of dental health studies and the influence of diverse confounding factors on their outcomes.

In the current study, different desensitizing materials showed a significant reduction in hypersensitivity, with no single material superior over one month. These results are similar to a systematic review where bonding agents have resulted in the immediate term and midterm reduction (one-month duration) in DH [38]. Bonding agents in this systematic review have shown efficacy similar to stannous fluoride, glutaraldehyde with HEMA, hydroxyapatite, glass ionomer cement and Laser groups in midterm reduction of DH [48]. A recent double-blind study compared the efficacy of Colgate Pro-Relief In-office, Admira Protect (Voco), and Bifluorid 12 (Voco) in a cohort of 40 patients diagnosed with DH. The study revealed that Bifluorid 12 demonstrated a more sustained desensitizing impact than Colgate Pro-Relief (applied in the office setting) in response to tactile and evaporative stimuli [38].

Our study demonstrated that seventh-generation dentin bonding agents and Bifluorid 12 were equally effective at reducing DH. No statistical difference was found in terms of their effectiveness and superiority over one another, as shown in Table 3. The results of this study hold important clinical implications, given that seventh-generation bonding agents, which consist of two components – etch and bond – are susceptible to varying degrees of solvent evaporation. Additionally, these agents are sensitive to technique and moisture, more time-intensive, and require multiple steps, making them costlier compared to the single-step application of Bifluorid 12.

This study’s design and execution incorporate several notable strengths, highlighting its contribution to the field of dentistry, particularly in the management of DH. A key feature of this research is its adoption of a double-blind methodology, a critical aspect in clinical trials aimed at reducing reporting bias. By ensuring that neither the participants nor the researchers were aware of the treatment allocation, the study significantly mitigates the potential for subjective influence on the outcomes, thereby enhancing the integrity and validity of the results.

Central to this study is its focus on evaluating less technique-sensitive desensitizing agents, specifically the seventh-generation dentin bonding agents. This choice reflects a thoughtful consideration of clinical practicality and efficacy. In treating DH, the ease and simplicity of the application process are crucial, especially in a clinical setting where time and resources are often limited. By providing empirical evidence supporting the use of these agents, the study makes a significant contribution to clinical practice, offering a viable and efficient alternative for treating DH.

Furthermore, the study distinguishes itself as a pioneering effort in its demographic context. It is the first in our population to compare seventh-generation dentin bonding agents and fluoride varnishes as desensitizers. This comparative approach not only broadens the understanding of the effectiveness of these treatments but also contextualizes their utility within a specific population, offering valuable insights for localized clinical practices.

The study innovatively employs subjective response measures to assess the desensitizing agents’ efficacy. While subjective responses can vary significantly among individuals, they provide crucial insights into the patient’s perspective and experience of relief, which is a central concern in clinical outcomes. This patient-centered approach to evaluating treatment efficacy reflects a holistic understanding of clinical success, transcending mere clinical measurements.

Recognizing the study’s constraints and opportunities for further inquiry, it should be noted that the research spanned a short follow-up period of just one month. This duration, while providing initial insights into the effectiveness of the treatments, opens avenues for subsequent studies with extended follow-up periods. Longer follow-up durations in future research could yield more comprehensive data, offering a deeper understanding of these treatments’ long-term efficacy and sustainability.

In conducting our research on the effectiveness of desensitizing materials for dental hypersensitivity, we recognized the potential influence of various confounding variables. These confounders were differences in participant characteristics (such as age, gender, and baseline oral health), individual variations in pain perception, adherence to oral hygiene practices, and environmental factors that could affect dental sensitivity.

To mitigate the impact of these confounding variables, our study design incorporated several methodological safeguards:

Our study’s foundation was a randomized controlled trial design. This strategy is pivotal in neutralizing the effects of both known and unknown confounders, thereby ensuring a fair comparison among the treatment modalities. The double-blind nature of our study played a critical role in minimizing biases. This approach was crucial in eliminating biases related to treatment administration and participant response, significantly reducing placebo effects and observer biases. We established stringent inclusion and exclusion criteria for creating a more uniform study population, reducing the impact of confounding variables related to individual dental health histories and systemic health conditions.

Before applying the desensitizing agents, all participants underwent a standardized treatment protocol, including non-surgical scaling and root debridement. Additionally, uniform oral hygiene instructions were provided to all participants. These standardized procedures ensured that each participant started with a similar baseline, thus reducing variability in initial oral health conditions. To ensure consistency in the application of outcome measures, our examiners underwent a thorough calibration process. This step was pivotal in minimizing inter-examiner variability, particularly in interpreting and applying the Discomfort Interval Scale and Schiff Cold Air Sensitivity Scale. The inclusion of a control group and the application of standardized measurement scales provided a structured framework for assessing treatment outcomes. This approach allowed for a more objective evaluation of the effectiveness of the desensitizing materials, reducing the influence of subjective biases.

Future studies should aim to extend the duration of follow-up periods. This will allow for a more comprehensive evaluation of desensitizing materials’ long-term efficacy and sustainability. The study underscores the importance of understanding and documenting oral hygiene practices in relation to DH. Future research should continue to explore how different hygiene habits impact the onset and severity of DH and how they may interact with the effectiveness of desensitizing agents. An important finding is the equivalency noted between different desensitizing agents in the short term. Future research should aim to build on this by comparing a broader range of agents over extended periods to determine the most effective and practical solutions for DH. Given the subjective nature of DH analysis, the results from different clinical trials must be interpreted with caution. Researchers and practitioners should consider the contextual and individual variations that might affect the study outcomes and their applicability in different clinical settings.

By implementing these recommendations, future research can significantly contribute to the understanding and management of Dentin Hypersensitivity, ultimately leading to more effective and patient-centric treatment approaches.