Abstracts

Introduction

Resin composites were introduced in the dental practice decades ago, substantially changing the concept of restorative treatments for tooth structure rehabilitation ¹1. Tyas MJ, Anusavice KJ, Frencken JE, Mount GJ. Minimal intervention dentistry - a review. FDI Commission Project 1-97. Int Dent J 2000; 50:1-12.^,22. Sheiham A. Minimal intervention in dental care. Med Princ Pract 2002; 11 Suppl 1:2-6.^,33. Frencken JE, Peters MC, Manton DJ, Leal SC, Gordan VV, Eden E. Minimal intervention dentistry for managing dental caries - a review. Int Dent J 2012; 62:223-43.. The long-term success for resin composites is well-established, with up to 30 years of reported longevity restorations establishing this as the most commonly used material for direct restorative procedures ⁴4. Pallesen U, van Dijken JWV. A randomized controlled 27 years follow up of three resin composites in class II restorations. J Dent 2015; 43:1547-58.^,55. Pallesen U, van Dijken JWV. A randomized controlled 30 years follow up of three conventional resin composites in class II restorations. Dent Mater 2015; 31:1232-44.. Improvements to the composite properties and in the application of these materials have been studied for years to improve the clinical success of restorations and reduce the technical sensitivity of procedures ⁶6. Ferracane JL. Resin composite - state of the art. Dent Mater 2011; 27:29-38..

The modifications of reinforcing fillers into conventional composites resins have enabled the production of universal composites that combine mechanical strength and esthetics for posterior and anterior applications ⁷7. Chen M-H. Update on dental nanocomposites. J Dent Res 2010; 89:549-60.^,88. Sideridou ID, Karabela MM, Vouvoudi EC. Physical properties of current dental nanohybrid and nanofill light-cured resin composites. Dent Mater 2011; 27:598-607.^,99. Maran BM, de Geus JL, Gutiérrez MF, Heintze S, Tardem C, Barceleiro MO, et al. Nanofilled/nanohybrid and hybrid resin-based composite in patients with direct restorations in posterior teeth: a systematic review and meta-analysis. J Dent 2020; 99:103407.. These modifications changed the state-of-the-art of resin composites and supported the application of nanocomposites for long-term retention of restorative procedures ⁷7. Chen M-H. Update on dental nanocomposites. J Dent Res 2010; 89:549-60.. The simplification of composite application is being studied by adopting bulk-fill strategies to avoid the need for the conventional 2mm-incremental technique and is implemented by modifying the monomer and filler compositions ¹⁰10. Leprince JG, Palin WM, Vanacker J, Sabbagh J, Devaux J, Leloup G. Physico-mechanical characteristics of commercially available bulk-fill composites. J Dent 2014; 42:993-1000.. The application of bulk-fill composites in direct restorations gained popularity in the clinical practice in recent years ¹¹11. Van Ende A, De Munck J, Lise DP, Van Meerbeek B. Bulk-fill composites: a review of the current literature. J Adhes Dent 2017; 19:95-109. while evidence has been generated ¹²12. Arbildo-Vega HI, Lapinska B, Panda S, Lamas-Lara C, Khan AS, Lukomska-Szymanska M. Clinical effectiveness of bulk-fill and conventional resin composite restorations: systematic review and meta-analysis. Polymers (Basel) 2020; 12:1786.^,1313. Cidreira Boaro LC, Pereira Lopes D, de Souza ASC, Lie Nakano E, Ayala Perez MD, Pfeifer CS, et al. Clinical performance and chemical-physical properties of bulk fill composites resin - a systematic review and meta-analysis. Dent Mater 2019; 35:e249-64..

The modifications to the restorative materials are well described in the literature, which recommends modifications to the standard-of-care in clinical practice. Although restorative treatments are responsible for a great number of interventions in dentistry ¹⁴14. Schwendicke F, Göstemeyer G, Blunck U, Paris S, Hsu L-Y, Tu Y-K. Directly placed restorative materials: review and network meta-analysis. J Dent Res 2016; 95:613-22., little information is known about the relationship between emerging evidence in the scientific field and their implementation in dental treatments ¹⁵15. Tracy SL. From bench-top to chair-side: how scientific evidence is incorporated into clinical practice. Dent Mater 2014; 30:1-15.^,1616. Chiappelli F. Evidence-based dentistry: two decades and beyond. J Evid Based Dent Pract 2019; 19:7-16.. The translation of scientific knowledge is a well-known challenge ¹⁵15. Tracy SL. From bench-top to chair-side: how scientific evidence is incorporated into clinical practice. Dent Mater 2014; 30:1-15.^,1717. Morris ZS, Wooding S, Grant J. The answer is 17 years, what is the question: understanding time lags in translational research. J R Soc Med 2011; 104:510-20.^,1818. Duda GN, Grainger DW, Frisk ML, Bruckner-Tuderman L, Carr A, Dirnagl U, et al. Changing the mindset in life sciences toward translation: a consensus. Sci Transl Med 2014; 6:264cm12.^,1919. Chambers D, Simpson L, Neta G, Schwarz U, Percy-Laurry A, Aarons GA, et al. Proceedings from the 9th annual conference on the science of dissemination and implementation. Implement Sci 2017; 12:48. since it requires the generation of high-quality evidence, its synthesis and dissemination in the academic field, and, most importantly, its transference into tangible information for the population. Thus, the relationship between the state-of-the-art and standard-of-care in restorative treatment is related to understanding the translation of knowledge, especially in large-scale public healthcare systems, of which the strategies may affect millions of people. Besides, since many purchases are made, the economic impact of such strategies must be considered ²⁰20. Langer A. A framework for assessing Health Economic Evaluation (HEE) quality appraisal instruments. BMC Health Serv Res 2012; 12:253.. This analysis may be valuable to optimize the implementation of innovation, adjusting the application of obsolete techniques, and providing health and cost-effective treatments for the population ²⁰20. Langer A. A framework for assessing Health Economic Evaluation (HEE) quality appraisal instruments. BMC Health Serv Res 2012; 12:253.^,2121. Liu W, Shi L, Pong RW, Dong H, Mao Y, Tang M, et al. Determinants of knowledge translation from health technology assessment to policy-making in China: from the perspective of researchers. PLoS One 2018; 13:e0190732..

The screening for resin composites procurements in one healthcare system may shed light on the current standard-of-care that is being provided, allowing for an economic analysis of the impact of purchased materials and technology implementation in the allocation of public resources. While the purchase of other health products have been analyzed ²²22. Caetano R, Hauegen RC, Osorio-de-Castro CGS. A incorporação do nusinersena no Sistema Único de Saúde: uma reflexão crítica sobre a institucionalização da avaliação de tecnologias em saúde no Brasil. Cad Saúde Pública 2019; 35:e00099619.^,2323. Pontes MA, Tavares NUL, Francisco PMSB, Naves JOS. Investment of financial resources for the procurement of medicines for primary care in Brazilian municipalities. Ciênc Saúde Colet 2017; 22:2453-62.^,2424. Chaves GC, Osorio-de-Castro CGS, Oliveira MA. Compras públicas de medicamentos para hepatite C no Brasil no período de 2005 a 2015. Ciênc Saúde Colet 2017; 22:2527-38., there have been no previous reports assessing the purchase patterns and economic impact of materials used for tooth restorations. This study aims to assess the resin composite purchases in a public health system and identify the variables associated with its cost and the decision-making process over a period of 10 years.

Methods

Data collection

In this longitudinal retrospective observational study, data collection was performed in the Brazilian Healthcare Prices Database (BDHP) of the Brazilian Ministry of Health from January 1^st, 2010 to December 31, 2019. The composite resin information was collected for different conventional composite resins according to their filler size. Flowable and bulk-fill composite information was collected as well. The data were reorganized into categories to perform the analysis. The institutions were categorized according to their location within the Brazilian macroregions. The procurement modality and the type of institutions were recategorized as well. The unit prices were collected in Brazilian Reais (BRL), and inflation was used to adjust the values from 2010-2019. The Extended National Consumer Price Index (IPCA) was applied based on the month and the year of purchase. The adjusted prices were converted to American Dollars (USD), and values were matched based on the day when the procurement was performed by the Central Bank of Brazil. The Consumer Price Index (CPI) from 2010 to 2019 was used to adjust the converted prices. All analyses were performed using Stata 14 (https://www.stata.com).

The number of the procurement process, the total number of purchased units, and the total cost of resin composites purchased were calculated. The average price for each category was collected and analyzed by one-way ANOVA and the Tukey’s test at a 5% significance level.

Conventional resin composites

A multiple linear regression model was used to evaluate the effect of the adjusted unit price on the collected variables. The class of conventional resin composite, the macroregion, the year of procurement, the type of institution, the procurement modality, and the manufacturer were included in the univariate analysis model. The significance was assessed for each variable considering α = 0.05, and the selected variables were included in the multinomial regression analysis using ordinary least square means. The model was used to assess outliers within the database. These values were removed in case the studentized residuals surpass 10 standard deviations, totaling 178 observations excluded (0.98% of the entries).

The probability of procurement was assessed with year, type of institution, price, procurement modality, and macroregion as the logistic model response variables. In this case, the unit price was divided by 10 for a better interpretation of the results. A chi-square univariate analysis was performed on the variables, and the multinomial model was adjusted with the variables that were statistically different (α = 0.05). The predictive margins were calculated based on the logistic model to estimate average probability for each variable based on the category reference (nanofilled).

Bulk-fill vs. conventional composites

Recategorization was performed in the material description to classify composites as conventional and bulk-fills to then compare their procurement process. The linear and logistic models were used to describe the influence of adjusted unit price in the procurement process and the odds of purchasing bulk-fills compared to conventional. All analyses were conducted as aforementioned.

Results

The collected data resulted in 18,138 observations that corresponded to 2,129,294 units of composites being purchased, from 2010 to 2019, with an average price of USD 22.25 ± 16.47 per unit and a total cost of USD 43,504,260.00 (Figure 1). Nanofilled composites were the most frequently purchased composite resin corresponding to 34.6% of the total purchased units, representing 41.2% of the total cost of composites in Brazil, in the analyzed period. The average adjusted unit price for these composites was USD 24.13 ± 14.04 (p < 0.05). Microhybrids were the cheapest materials in this analysis, with an average price of USD 16.44 ± 14.62 (p < 0.05), corresponding to 18% of the total purchased units. From the total amount of procurements, 1.5% corresponded to bulk-fill composites, that were purchased for the highest average adjusted unit prices (USD 30.57 ± 13.87; p < 0.05), corresponding to 2.2% of the overall expenditure.

Table 1 shows the linear model for conventional composites. All analyzed variables were statistically significant, being used in the multiple analysis. The reference categories were the most frequent categories in the databank for each variable. The unit price analysis is shown in the adjusted model, considering the predictor variables. The nanofilled composites were used as the reference category, and only the nanohybrids were more expensive than the reference (USD 1.58; p = 0.001), whereas the other categories presented reduced coefficients when compared to the reference. All macroregions presented reduced prices when compared to the reference (Southeast). The procurement modality was shown to influence the price of composites. When compared to the reference category (auction), the bid waiver and other modalities increased the unit price to USD 8.79 and USD 3.77 in the adjusted model, respectively. Universities paid USD 1.67 less than other federal institutions (Table 1; p = 0.001). The manufacturer analysis showed that the reference category (3M) has higher values in the adjusted model when compared to 13 out of 17 manufacturers. Ivoclar, Shofu, and Voco composites were purchased for higher values when compared with 3M.

Tables 2 and 3 show the individual analysis for each category and the multinomial logistic regression model among conventional composites. All response variables were statistically significant in the analysis; thus, all were included in the multinomial logistic regression where the type of composite was used as the response variable. The odds for purchasing hybrids, microfills, and microhybrids decreased from 2010 to 2019 when compared with nanofilled composites. Nanohybrid resin composites were more likely to be purchased over the years when compared with nanofilleds (OR = 1.04; p < 0.001). For each USD 10.00 increase in the price, a reduction in the odds is observed for the purchase of hybrids, microfills, microhybrids, and flowable; whereas an increase is observed for nanohybrids (OR = 1.07; p < 0.001). Universities were more likely to purchase microfills and nanohybrid resins when compared with nanofilled, whereas reduced odds were found for hybrids, microhybrids, and flowable.

The conventional composites were grouped in a single category to compare these materials with bulk-fill composites. The price and the type of composites were used in the regression models as aforementioned. Table 4 summarizes the linear regression models with the price as the predictor for the response variables; the multiple regression model results are found in Figures 2 and 3 and in Tables 5 and 6. The bulk-fill composites were purchased for a higher price (Table 4; USD 15.45; p < 0.01) when compared with the conventional ones, when adjusted for all response variables. The other response variables followed the findings of the price analysis performed for the conventional composites. The year, the procurement modality, the type of institution, and the manufactures influenced the unit price.

Compared with the conventional composites, the probability of purchasing the bulk-fill composites was modeled with a logistic model. An increase in the probability of purchasing the bulk-fill composites is observed over time, when compared with the conventional ones (Figure 2; OR = 3.14; p < 0.01). For each USD 10.00 increase, the odds of purchasing the bulk-fill increased by 64% (Figure 3). The North region presented a 5x higher probability of bulk-fill purchase when compared to the Southeast region (Figure 4). Universities were less likely to purchase bulk-fill composites than conventional resins when compared with other federal institutions (Figure 4; OR = 0.55; p < 0.01).

Discussion

Over the years, changes in the resin composites formulations modified their physicomechanical properties and their application in restorative treatments, leading to the incorporation of new materials in the market share ⁶6. Ferracane JL. Resin composite - state of the art. Dent Mater 2011; 27:29-38.^,77. Chen M-H. Update on dental nanocomposites. J Dent Res 2010; 89:549-60.. Among several attempts to increase their clinical effectiveness, the particle size modifications towards the nanoscale were shown to improve their properties, supporting the application of these materials in the clinical scenario. However, it is not clear how this knowledge affects the establishment of public policies in large-scale public health systems. In this study, we screened public procurements within a public health system, assessing the variables that may influence this process. Nanofilled resin composites were the most purchased materials over the 10 years analyzed, compared with other conventional composites. All analyzed variables influenced the unit price of resin composites, and they predicted an increase in the odds of purchasing nanofilled and nanohybrid composites over time. Bulk-fill composites are increasingly being purchased in the public system with higher costs when compared with conventional composites.

Conventional composites corresponded to 98.5% of the total purchased items from 2010 to 2019 in the data from the BDHP (Figure 1). The reinforcing fillers characteristics divided the conventional composites in the database, and this information was used to compare the materials in this class of resin composites according to a previously reported classification ⁶6. Ferracane JL. Resin composite - state of the art. Dent Mater 2011; 27:29-38.. Nanofilled composites are the most purchased materials showing that the collected data follows the current evidence that classifies the nanofilled and nanohybrid resin composites as being a state-of-the-art material within the field ⁶6. Ferracane JL. Resin composite - state of the art. Dent Mater 2011; 27:29-38.. The nanocomposite formulation was the most recent formulation of conventional resin composites; which allows for the incorporation of increased amounts of fillers into the base resin and contributes to lower polymerization shrinkage, increased physical properties, and enhanced aesthetics ⁷7. Chen M-H. Update on dental nanocomposites. J Dent Res 2010; 89:549-60.. Laboratory ⁸8. Sideridou ID, Karabela MM, Vouvoudi EC. Physical properties of current dental nanohybrid and nanofill light-cured resin composites. Dent Mater 2011; 27:598-607.^,2525. da Silva EM, Poskus LT, Guimarães JGA. Influence of light-polymerization modes on the degree of conversion and mechanical properties of resin composites: a comparative analysis between a hybrid and a nanofilled composite. Oper Dent 2008; 33:287-93. and clinical ²⁶26. Demirci M, Tuncer S, Sancakli HS, Tekçe N, Baydemir C. Five-year clinical evaluation of a nanofilled and a nanohybrid composite in class IV cavities. Oper Dent 2018; 43:261-71.^,2727. Yazici AR, Antonson SA, Kutuk ZB, Ergin E. Thirty-six-month clinical comparison of bulk fill and nanofill composite restorations. Oper Dent 2017; 42:478-85.^,2828. Palaniappan S, Bharadwaj D, Mattar DL, Peumans M, Van Meerbeek B, Lambrechts P. Nanofilled and microhybrid composite restorations: five-year clinical wear performances. Dent Mater 2011; 27:692-700.^,2929. Sadeghi M, Lynch CD, Shahamat N. Eighteen-month clinical evaluation of microhybrid, packable and nanofilled resin composites in class I restorations. J Oral Rehabil 2010; 37:532-7. data suggest that nanocomposite formulation may present different behavior compared to microfilled compositions, showing better mechanical properties or increased long-term success for restorative treatments ⁶6. Ferracane JL. Resin composite - state of the art. Dent Mater 2011; 27:29-38.. Despite differences in their composition, the annual failure rates for resin composite restorations are close to 2% regardless of the filler size ²⁶26. Demirci M, Tuncer S, Sancakli HS, Tekçe N, Baydemir C. Five-year clinical evaluation of a nanofilled and a nanohybrid composite in class IV cavities. Oper Dent 2018; 43:261-71.^,3030. van Dijken JWV, Pallesen U. A randomized 10-year prospective follow-up of class II nanohybrid and conventional hybrid resin composite restorations. J Adhes Dent 2014; 16:585-92.^,3131. da Rosa Rodolpho PA, Cenci MS, Donassollo TA, Loguércio AD, Demarco FF. A clinical evaluation of posterior composite restorations: 17-year findings. J Dent 2006; 34:427-35.. Recently, the clinical evidence comparing hybrid composites with nanofilled and nanohybrids was systematically performed, showing no difference in surface features, risk of fracture, loss of restoration, and annual failure rates between different filled composites ⁹9. Maran BM, de Geus JL, Gutiérrez MF, Heintze S, Tardem C, Barceleiro MO, et al. Nanofilled/nanohybrid and hybrid resin-based composite in patients with direct restorations in posterior teeth: a systematic review and meta-analysis. J Dent 2020; 99:103407.^,3232. Angerame D, De Biasi M. Do nanofilled/nanohybrid composites allow for better clinical performance of direct restorations than traditional microhybrid composites? A systematic review. Oper Dent 2018; 43:E191-209.. Despite conflicting results being found in the laboratory and clinical evidence, it is possible to observe that nanocomposites are well-established within the analyzed data, considering that these materials were more recently included in the market. The year significantly predict an increase in the purchase of nanohybrids and reduction in the purchase of hybrids, microfilled, and microhybrids composites when compared with nanofilled. The increase in the probability of purchasing nanocomposites is observed even considering their higher costs. However, the year predicted a reduction in the average unit price in the adjusted model (Table 1; -USD 2.61/year; p < 0.001), contributing to the reduction in prices of these materials. Although nanocomposites were the newest materials among the conventional composites, their effectiveness was described in the early 2010s, and thus, it is expected that the translation of knowledge associated with these materials had overcome the gap between research and clinical practice ¹⁵15. Tracy SL. From bench-top to chair-side: how scientific evidence is incorporated into clinical practice. Dent Mater 2014; 30:1-15.. The reduction in prices also corroborate with the increase in popularity of nanocomposites.

Besides the year of purchase, all other variables influenced the unit price of resin composites (Table 1). The adjusted model shows that the reinforcing filler drives differences in the unit price, and when compared to nanofilled composites, only the nanohybrids are purchased at higher prices (1.58; p < 0.001). Also, for each increase in USD 10.00 in the unit price, the nanohybrids were 7% more likely to be purchased, whereas hybrids, microfilled, microhybrids, and all flowable composites were less likely to be chosen when compared with nanofilled composites (Table 2). While the differences among composite prices may affect the total amount spent in a public health system, people responsible for public procurements must critically evaluate the cost-effectiveness of the restorative treatments in the formulation of public policies for materials purchase. The development of new composites for dental restorations aims to improve the quality of treatments, and new materials are constantly being developed in the field ³³33. Attik N, Hallay F, Bois L, Brioude A, Grosgogeat B, Colon P. Mesoporous silica fillers and resin composition effect on dental composites cytocompatibility. Dent Mater 2017; 33:166-74.^,3434. Chiari MDS, Rodrigues MC, Xavier TA, de Souza EMN, Arana-Chavez VE, Braga RR. Mechanical properties and ion release from bioactive restorative composites containing glass fillers and calcium phosphate nano-structured particles. Dent Mater 2015; 31:726-33.^,3535. Balbinot GS, Leitune VCB, Ogliari FA, Collares FM. Niobium silicate particles as bioactive fillers for composite resins. Dent Mater 2020; 36:1578-85.. The economic impact of the implementation of new technologies is known to happen in other areas of healthcare ³⁶36. Pantoja T, Opiyo N, Lewin S, Paulsen E, Ciapponi A, Wiysonge CS, et al. Implementation strategies for health systems in low-income countries: an overview of systematic reviews. Cochrane Database Syst Rev 2017; (9):CD011086., and this may be balanced with the possible benefits of these technologies for the population primarily based on the effectiveness of these materials. While the price may influence the decision-making process, it does not uniquely determine the treatment cost. Public managers must consider the overall cost for implementation of new materials in a broad sense, considering direct costs for treatment and possible retreatments, as well as the indirect and intangible costs related to the population’s health and quality of life ³⁷37. Schwendicke F, Meyer-Lueckel H, Stolpe M, Dörfer CE, Paris S. Costs and effectiveness of treatment alternatives for proximal caries lesions. PLoS One 2014; 9:e86992.^,3838. Listl S, Galloway J, Mossey PA, Marcenes W. Global economic impact of dental diseases. J Dent Res 2015; 94:1355-61..

The price differences may also be explained by socioeconomic characteristics found over the country, the type of institution, and the procurement modality. These factors may influence access to information in different places and institutions, impacting the decision-making process and the establishment of evidence-based practices in the selection of materials ³⁹39. Dobrow MJ, Goel V, Upshur REG. Evidence-based health policy: context and utilisation. Soc Sci Med 2004; 58:207-17.. Universities may be more up-to-date in the advances in the scientific field, and this may facilitate the two-way interaction in the knowledge translation, between research findings and the clinical practice ³⁹39. Dobrow MJ, Goel V, Upshur REG. Evidence-based health policy: context and utilisation. Soc Sci Med 2004; 58:207-17.. We observed that universities are more likely to choose nanocomposites in their composite procurements, when compared with other federal institutions (Table 2), highlighting a possible slower translation of knowledge in non-academic fields. Although universities are more prone to purchase nanocomposites, the adjusted unit price in the procurement process is lower when compared with other institutions (Table 1; -USD 1.67; p < 0.01). Controlling the unit price in these public procurements is complicated, since many variables are involved in the process; however, the modeled data suggest that procurement processes that are performed under the auction modality may be efficient in reducing prices, even when the most expensive materials are chosen (Table 1). This modality is recommended by regulatory agencies ²³23. Pontes MA, Tavares NUL, Francisco PMSB, Naves JOS. Investment of financial resources for the procurement of medicines for primary care in Brazilian municipalities. Ciênc Saúde Colet 2017; 22:2453-62.^,4040. Kohler JC, Mitsakakis N, Saadat F, Byng D, Martinez MG. Does pharmaceutical pricing transparency matter? Examining Brazil's public procurement system. Global Health 2015; 11:34. and could be an effective strategy to establish rationality in the public expenditure to achieve cost-effectiveness in the health system.

The most recent innovation in the field of resin composites is low-shrinkage materials ⁶6. Ferracane JL. Resin composite - state of the art. Dent Mater 2011; 27:29-38.. The bulk-fill composites were developed based on a simplification concept to guarantee an adequate polymerization, without the need for incremental technique ¹¹11. Van Ende A, De Munck J, Lise DP, Van Meerbeek B. Bulk-fill composites: a review of the current literature. J Adhes Dent 2017; 19:95-109.. Despite the conflicting results found in in vitro attempts to reduce the shrinkage in these materials, recent data supported their application on direct restorative procedures with comparable results to conventional composites ¹²12. Arbildo-Vega HI, Lapinska B, Panda S, Lamas-Lara C, Khan AS, Lukomska-Szymanska M. Clinical effectiveness of bulk-fill and conventional resin composite restorations: systematic review and meta-analysis. Polymers (Basel) 2020; 12:1786.^,4141. Kruly PC, Giannini M, Pascotto RC, Tokubo LM, Suga USG, Marques ACR, et al. Meta-analysis of the clinical behavior of posterior direct resin restorations: low polymerization shrinkage resin in comparison to methacrylate composite resin. PLoS One 2018; 13:e0191942.. The BDHP registered the first bulk-fill purchase only in 2017, and the number of analyzed processes corresponds to 1.5% of all procurements for resin composites (Figure 1). However, from 2017 an increase in the number of purchased bulk-fills is observed regardless of their higher cost (Table 4). This result is followed by logistic regression findings that show an increase in the odds of purchasing bulk-fill, instead of a conventional composite, as the price increased (Figure 2; Table 6).

The trend for an increase in the bulk-fill procurement process in the last years is observed in the predictive margins that calculate the average probability in the response variable, based on the predictors in the adjusted model (Figure 3). The logistic model predicts 3.14x higher odds of purchasing bulk-fill composites for each price increase over the years when compared with the conventional ones (Figure 3; Tables 5 and 6). The simplification appeal for this type of composites contributed to its popularity among dentists in the last years, as growing evidence is being generated showing laboratory ¹³13. Cidreira Boaro LC, Pereira Lopes D, de Souza ASC, Lie Nakano E, Ayala Perez MD, Pfeifer CS, et al. Clinical performance and chemical-physical properties of bulk fill composites resin - a systematic review and meta-analysis. Dent Mater 2019; 35:e249-64.^,4242. Lins RBE, Aristilde S, Osório JH, Cordeiro CMB, Yanikian CRF, Bicalho AA, et al. Biomechanical behaviour of bulk-fill resin composites in class II restorations. J Mech Behav Biomed Mater 2019; 98:255-61.^,4343. Sampaio CS, Fernández Arias J, Atria PJ, Cáceres E, Pardo Díaz C, Freitas AZ, et al. Volumetric polymerization shrinkage and its comparison to internal adaptation in bulk fill and conventional composites: a µCT and OCT in vitro analysis. Dent Mater 2019; 35:1568-75.^,4444. Ilie N, Bucuta S, Draenert M. Bulk-fill resin-based composites: an in vitro assessment of their mechanical performance. Oper Dent 2013; 38:618-25. and clinical ¹²12. Arbildo-Vega HI, Lapinska B, Panda S, Lamas-Lara C, Khan AS, Lukomska-Szymanska M. Clinical effectiveness of bulk-fill and conventional resin composite restorations: systematic review and meta-analysis. Polymers (Basel) 2020; 12:1786.^,1313. Cidreira Boaro LC, Pereira Lopes D, de Souza ASC, Lie Nakano E, Ayala Perez MD, Pfeifer CS, et al. Clinical performance and chemical-physical properties of bulk fill composites resin - a systematic review and meta-analysis. Dent Mater 2019; 35:e249-64.^,4545. Heck K, Manhart J, Hickel R, Diegritz C. Clinical evaluation of the bulk fill composite QuiXfil in molar class I and II cavities: 10-year results of a RCT. Dent Mater 2018; 34:e138-47.^,4646. Karaman E, Keskin B, Inan U. Three-year clinical evaluation of class II posterior composite restorations placed with different techniques and flowable composite linings in endodontically treated teeth. Clin Oral Invest 2017; 21:709-16.^,4747. van Dijken JWV, Pallesen U. Posterior bulk-filled resin composite restorations: a 5-year randomized controlled clinical study. J Dent 2016; 51:29-35.^,4848. van Dijken JWV, Pallesen U. Bulk-filled posterior resin restorations based on stress-decreasing resin technology: a randomized, controlled 6-year evaluation. Eur J Oral Sci 2017; 125:303-9. outcomes related to these materials. Notably, these procurements still represent a small fraction of the overall process and this is not consistent with the institutions in the country. The universities are 45% less prone to purchase bulk-fills when compared to other federal institutions (OR = 0.55; p < 0.01), while the most developed region (Southeast) in the country is less likely to purchase bulk-fills when compared with the other regions (Table 6). These results are contrary to the conventional composites results, in which the institutions that are more closely related to the scientific knowledge were more likely to purchase newly developed materials. In this case, the difference could be related to the maturity in the evidence to support the large-scale implementation of healthcare technologies ²¹21. Liu W, Shi L, Pong RW, Dong H, Mao Y, Tang M, et al. Determinants of knowledge translation from health technology assessment to policy-making in China: from the perspective of researchers. PLoS One 2018; 13:e0190732.^,3636. Pantoja T, Opiyo N, Lewin S, Paulsen E, Ciapponi A, Wiysonge CS, et al. Implementation strategies for health systems in low-income countries: an overview of systematic reviews. Cochrane Database Syst Rev 2017; (9):CD011086.. While innovation is desired - and the gap between scientific development and clinical practice should be narrowed - the establishment of synthesized evidence of its effectiveness and the translation of this information may take time ¹⁷17. Morris ZS, Wooding S, Grant J. The answer is 17 years, what is the question: understanding time lags in translational research. J R Soc Med 2011; 104:510-20.. The synthesized evidence about the clinical effectiveness of bulk-fill composites is recent ¹²12. Arbildo-Vega HI, Lapinska B, Panda S, Lamas-Lara C, Khan AS, Lukomska-Szymanska M. Clinical effectiveness of bulk-fill and conventional resin composite restorations: systematic review and meta-analysis. Polymers (Basel) 2020; 12:1786.^,1313. Cidreira Boaro LC, Pereira Lopes D, de Souza ASC, Lie Nakano E, Ayala Perez MD, Pfeifer CS, et al. Clinical performance and chemical-physical properties of bulk fill composites resin - a systematic review and meta-analysis. Dent Mater 2019; 35:e249-64., and these studies highlight the need for further analysis with long-term follow-ups to support their findings. Strategies for the implementation of new technologies and material in restorative dentistry are limited, and they are usually centered in an individual experience ⁴⁹49. Rindal DB, Flottemesch TJ, Durand EU, Godlevsky OV, Schmidt AM, Gilbert GH, et al. Practice change toward better adherence to evidence-based treatment of early dental decay in the National Dental PBRN. Implement Sci 2014; 9:177.^,5050. Innes NPT, Schwendicke F. Restorative thresholds for carious lesions: systematic review and meta-analysis. J Dent Res 2017; 96:501-8.^,5151. Afrashtehfar KI, Eimar H, Yassine R, Abi-Nader S, Tamimi F. Evidence-based dentistry for planning restorative treatments: barriers and potential solutions. Eur J Dent Educ 2017; 21:e7-18.^,5252. Afrashtehfar KI, Assery MK. From dental science to clinical practice: knowledge translation and evidence-based dentistry principles. Saudi Dent J 2017; 29:83-92. or generic recommendations for healthcare services ⁵³53. Andrade KRC, Pereira MG. Knowledge translation in the reality of Brazilian public health. Rev Saúde Pública 2020; 54:72.^,5454. Ravioli AF, De Soárez PC, Scheffer MC. Modalidades de gestão de serviços no Sistema Único de Saúde: revisão narrativa da produção científica da Saúde Coletiva no Brasil (2005-2016). Cad Saúde Pública 2018; 34:e00114217.. Technology assessments and horizon scanning for healthcare technologies, usually for new drugs, are recommended by the Brazilian Ministry of Health in the attempt to identify emerging technologies from research and development process, understand its adoption and performance allowing rational decisions in the modifications of healthcare patterns ⁵⁵55. Gomes PTC, Mata VE, Borges TC, Galato D. Horizon scanning in Brazil: outputs and repercussions. Rev Saúde Pública 2019; 53:111.^,5656. Hines P, Yu LH, Guy RH, Brand A, Papaluca-Amati M. Scanning the horizon: a systematic literature review of methodologies. BMJ Open 2019; 9:e026764.^,5757. Ministério da Saúde. Monitoramento do horizonte tecnológico no Brasil: avanços e desafios. Brasília: Ministério da Saúde; 2018.. The use of implementation strategies in Dentistry, and especially in restorative treatments, may contribute towards the use of simplified composites in the public system. Changes may be performed with caution, especially considering the economic impact observed in this analysis (Figure 2).

In this study, secondary data were used to evaluate resin composite purchases, and such databases have limitations. The BDHP is filled by local managers in different institutions over the country following no standardization, which introduces random and measurement errors in the registration process. Although inconsistencies were detected in the current data, sensitivity analysis was performed to assess the impact of such issues. The results were robust and the conclusions remained unchanged. The high number of purchases registered over the last 10 years provide significant data for analysis and it is expected that the adherence to government recommendations, for product registration in the database, may contribute to future studies and for the formulations of public policies in the purchase of healthcare products for restorative treatments. Understanding the type of resin composite used in the public health system, considering the characteristics of this process, shows the importance of an evidence-based decision-making process by public institutions to maintain and to improve the quality of provided restorative treatments. The differences between institutions over the country must be considered in the attempt to draw strategies for better allocation of resources in the purchase of clinical and cost-effective materials. The continuous analysis of evidence and the application of strategies to control prices could contribute to the implementation of new technologies to improve healthcare and to minimize the impact of these materials on public resources. Assessing the adherence to scientific evidence in the clinical practice over time may also contribute to the interaction between research and development areas to produce improved materials in consonance with the population’s needs.

Conclusions

The procurement processes in this 10-year analysis were mostly performed to purchase nanofilled conventional composites. In the most recent year, procurements conducted in universities were made by the auction modality at lower prices when considering the conventional and the bulk-fill composites. The conventional nanocomposites and bulk-fill resin composites were increasingly purchased over the years, despite the predicted higher unit prices of the items. These findings highlight possible modifications to the standard-of-care provided in the analyzed public health system, how the prices may influence the market share, and how the translation of knowledge may occur from the development of new materials to their clinical application.

Acknowledgments

G. S. Balbinot would like to thank the Brazilian Graduate Studies Coordinating Board (CAPES; finance code 001). R. K. Celeste, V. C. B. Leitune, and F. M. Collares are scholarship researchers for the Brazilian National Research Council (CNPq; PQ2).

References

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