International Journal of Prosthodontics and Restorative Dentistry
Volume 13 | Issue 4 | Year 2023

Evaluation of Composite Restoration in Posterior Teeth with Proanthocyanidin Pretreatment Liner Using Fédération Dentaire Internationale Criteria: A Split-mouth Randomized Controlled Trial

Lakshmi C Padarthi1https://orcid.org/0009-0006-1379-3371, Lavanya Anumula2https://orcid.org/0000-0002-0930-8445, Suneel K Chinni3https://orcid.org/0000-0002-2668-2316, Swapna Sannapureddy4https://orcid.org/0000-0002-6363-8242, Kiranmayi Govula5https://orcid.org/0000-0001-8106-7634, Sindhu Ramesh6https://orcid.org/0000-0001-8022-2815

1Department of Conservative Dentistry and Endodontics, Amrutha Multi Speciality Dental Clinic, Jammalamadugu, Andhra Pradesh, India

2Department of Conservative Dentistry and Endodontics, Narayana Dental College and Hospital, Nellore, Andhra Pradesh; Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences (SIMATS) (Deemed to be University), Chennai, Tamil Nadu, India

3–5Department of Conservative Dentistry and Endodontics, Narayana Dental College and Hospital, Nellore, Andhra Pradesh, India

6Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences (SIMATS) (Deemed to be University), Chennai, Tamil Nadu, India

Corresponding Author: Lavanya Anumula, Department of Conservative Dentistry and Endodontics, Narayana Dental College and Hospital, Nellore, Andhra Pradesh; Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences (SIMATS) (Deemed to be University), Chennai, Tamil Nadu, India, Phone: +91 9182627413, e-mail: lavanyamds@gmail.com

Received: 16 September 2023; Accepted: 15 November 2023; Published on: 30 December 2023


Purpose: A split-mouth randomized controlled trial (RCT) to evaluate the impact of a 2% proanthocyanidin (PAC) pretreatment liner on the clinical durability of posterior composite restorations.

Materials and methods: A parallel double-blinded split-mouth RCT adhering to Consolidated Standards of Reporting Trials (CONSORT) guidelines was conducted. A 2% PAC solution was prepared for pretreatment. A total of 44 participants meeting inclusion criteria received composite restorations, each receiving one restoration with PAC liner and one without (test and control). Clinical evaluations include esthetic, functional, and biological aspects over a 6-month and 1-year follow-up period using Fédération Dentaire Internationale (FDI) criteria. Fisher exact test was employed to analyze the differences in ratings between the two groups.

Results: No significant differences were observed between the two groups (p < 0.05). Staining was minimal and comparable between the two groups; neither group experienced postoperative sensitivity or recurrent caries. Both groups exhibited excellent outcomes in surface luster, color match, translucency, and marginal adaptation, with no significant differences between groups. Staining, postoperative sensitivity, and recurrent caries were minimal and comparable. General and oral health remained favorable in both groups during follow-up.

Conclusion: Around 2% PAC pretreatment enhances the clinical durability of posterior composite restorations, leading to excellent esthetic, functional, and biological outcomes. PAC represents a promising dentin biomodification agent for improving restoration performance and longevity.

How to cite this article: Padarthi LC, Anumula L, Chinni SK, et al. Evaluation of Composite Restoration in Posterior Teeth with Proanthocyanidin Pretreatment Liner Using Fédération Dentaire Internationale Criteria: A Split-mouth Randomized Controlled Trial. Int J Prosthodont Restor Dent 2023;13(4):191–200.

Source of support: Nil

Conflict of interest: None

Keywords: Adhesives, Antioxidants, Collagen, Esthetics proteases


Composite restorations have emerged as the preferred option for restoring posterior teeth, owing to their conservative approach and excellent esthetic properties. They provide a superior alternative to traditional amalgam restorations and have revolutionized restorative dentistry.1 Although their long-term success is still being studied, modern biomaterials research has applauded composite restorative materials’ ability to mimic biological tissue in both form and function.2 Using composite materials in posterior direct restoration placements has become standard practice, but the persistent challenges of polymerization shrinkage and hydrolysis of the hybrid layer have hindered the long-term durability and integrity of these restorations.3

The gradual breakdown of the hybrid layer in composite restorations, caused by the degradation of collagen fibers, underscores the necessity for new approaches to improve their effectiveness in clinical applications.4 Matrix metalloproteinases (MMPs) produced by dentin matrix cells, as zymogens (inactive enzymes), play a significant role in this process. Their activation is triggered when the pH levels are lowered to 4.5 or below, as in the case of carious lesions.5 These proteolytic enzymes require zinc and calcium for their activity and are responsible for the degradation of various extracellular matrix (ECM) components, particularly collagen.4 Incomplete resin monomer envelopment of collagen fibrils during bonding protocols renders them susceptible to collagenolytic enzyme degradation, which may compromise the integrity of dentin–resin bonds.5,6 The degradation of collagen fibrils in vivo has also been associated with the activation of MMPs induced by the application of dentinal adhesive systems.7

Two strategies have been explored to stabilize the adhesive interface—the use of nonselective MMP inhibitors, such as chlorhexidine and dentin biomodification.8 Biomodification of dentin, a promising biomimetic therapy, aims to strengthen the collagen network and regulate the degradation of ECM components.9 This approach holds great potential for improving the overall mechanical properties and resilience of dental tissues. The biomodifying agents or cross-linkers can be classified as physical (e.g., ultraviolet light), synthetic (e.g., glutaraldehyde), and natural origin [e.g., genipin, proanthocyanidin (PAC)].

Proanthocyanidin (PAC) is a natural cross-linking agent with potent antioxidant properties that demonstrated exceptional free radical scavenging activity while being minimally toxic.10 It has gained garnered attention for its biocompatibility and various biological benefits, including its ability to inhibit cancer development, reduce inflammation, combat bacteria, and stimulate the immune system.11 PACs form stable complexes with collagen, through hydrogen bonding between the protein amide carbonyl and the phenolic hydroxyl group and also covalent and hydrophobic bonds. PACs-protein complexes have demonstrated a remarkable level of stability, implying a high degree of structural specificity.12 Moreover, its potential for dental applications has expanded due to its ability to inhibit protease activity and interact with proteoglycans in a nonspecific manner.9

Literature has consistently demonstrated the significant impact of PAC on various dental aspects, such as inhibiting the growth of cariogenic bacteria,13 reducing oxidative stress,11 and improving the bond strength of adhesive materials to dentin.14 Several studies15 have highlighted the potential benefits of PAC in enhancing the durability and clinical performance of composite restorations.15,18 However, while these findings offer promising insights, a comprehensive and well-structured randomized controlled trial (RCT) is warranted to validate and quantify the effects of PAC pretreatment on posterior composite restorations accurately.

The purpose of the study was to assess the clinical durability of resin composite as a posterior restoration on dentin, both with and without PAC pretreatment liner, using Fédération Dentaire Internationale (FDI) criteria over a 6-month and 1-year follow-up period. The null hypothesis was that there was no difference in the clinical performance of composite restoration in groups with or without PAC as a pretreatment liner.


Study Design

The study followed a parallel double-blinded, equal allocation rate, split-mouth RCT design, adhering to the Consolidated Standards of Reporting Trials (CONSORT) statement.19 The study received approval from the Institutional Ethical Committee (IEC) of Narayana Dental College and Hospital, with Protocol No. NDC/IECC/CONS/12 - 17/01 and IEC No: D178401012. Before the study began, all patients were provided with an explanation of the study’s purpose, nature, and design. They were also required to provide written informed consent indicating their willingness to participate.


Participants were selected from the Outpatient Department of Conservative Dentistry and Endodontics, based on their order of arrival for the screening session. This formed a convenience sample. No advertisement was made for participant recruitment. A total of 44 individuals, aged 18–40, who were in good general health were evaluated to determine if they met the criteria for inclusion. The evaluations were conducted with the use of a mouth mirror, explorer, and periodontal probe.

Inclusion and Exclusion Criteria

Participants requiring at least two class-I restorations with good oral hygiene, that is, with occlusal caries scoring 4 or 5 on the International Caries Detection and Assessment System (ICDAS) classification,20 17 with normal occlusion were considered for inclusion. Patients with fewer than 20 teeth, existing tooth sensitivity, and bruxism, as well as nonvital teeth, were excluded. Additionally, pregnant or breastfeeding individuals were also excluded from the study.

Sample Size

To ensure accurate comparisons between material groups, a sample size of 40 participants was determined based on an effect size of 0.80, an α-value of 0.05, 80% power, and an anticipated dropout rate. This sample size was deemed sufficient for detecting significant differences.

Randomization and Blinding

This study employed block randomization, utilizing blocks of four with two odd and two even numbers taken from the random table. Restorations will be performed using PAC for odd numbers (group l) and without, for even numbers (group ll), as noted in the case sheet. The randomization was done on an intraindividual basis making sure that each subject received two restorations (Fig. 1). Both the participants and the examiners were blinded to the procedure and group allocation.

Fig. 1: Consolidated Standards of Reporting Trials (CONSORT) flow diagram depicting the enrolment, allotment, follow-up at different intervals, and analysis of the number of participants in the clinical trial

Allocation and Concealment

An individual who was not involved in the study assigned eligible patients to either arm of the study without knowledge of its details. The allocation was then documented and sealed. During treatment, the person in charge opens the sealed cover and determines whether it is odd or even before proceeding.

Preparation of PAC Solution

Purified PAC from grape seed extract was obtained from Sigma-Aldrich. A 2% PAC solution was prepared by mixing 2 gm of PAC with 100 mL of distilled water.21


To ensure consistency, all restorative procedures were performed by the same operator. Before treatment, periapical radiographs were taken and sensibility test scores were noted. Tooth preparation was done with 245 burs (Mani, Inc. Tokyo, Japan) and cavity depth was evaluated. Only cavities with a depth of <3 mm were included in the study. Acid-etching with 37% phosphoric acid (N-etch, Ivoclar Vivadent, Schaan, Liechtenstein) was done for 15 seconds, followed by a rinse with water for one minute and blot drying. In this study, the moist bonding technique was used. The etch and rinse bonding agent (Tetric-N-Bond, Ivoclar Vivadent, Schaan, Liechtenstein) was applied and light-cured for 20 seconds, followed by the placement of composite restoration using an incremental technique (Fig. 2, control group). The composite was light-cured for 20 seconds21 (Ivoclar Bluephase N, Ivoclar Vivadent, Schaan, Liechtenstein). This formed the control group.

Figs 2A to F: Clinical steps for placing composite restoration without pretreatment liner (control group). (A) Carious lesion (ICDAS 4); (B) Tooth preparation and depth evaluation; (C) Total etching (followed by rinsing and drying); (D) Application of bonding agent; (E) Light curing of the bonding agent; (F) Composite restoration

The contralateral experimental tooth preparations received the same treatment, except that the acid-etched dentin was treated with 2% PAC as a pretreatment liner (Fig. 3, test group). The excess solution was blot-dried after a dwell time of 60 seconds before the application of adhesive and composite. Finally, contouring and finishing of the restorations for both groups was done (Shofu finishing and polishing kit, Shofu Inc. Tokyo, Japan).

Figs 3A to F: Clinical steps for placing composite restoration with proanthocyanidin pretreatment liner. (A) Carious lesion (ICDAS 4); (B) Tooth preparation and depth evaluation; (C) Total etching (followed by rinsing and drying); (D) Application of proanthocyanidin pretreatment liner for a minute and dried; (E) Application of bonding agent followed by curing; (F) Composite restoration


The primary outcome was the long-term durability of composite restorations. Secondary outcomes included esthetic properties (surface luster, color match, staining, and esthetic anatomical form), functional properties (fracture of material and retention, marginal adaptation, and radiograph evaluation), and biological properties (postoperative sensitivity, reoccurrence of caries, general, and oral health) (Table 1).22

Table 1: Selected FDI esthetic, functional, and biological criteria for evaluating the restorations at baseline, 6, and 12 months
Properties Criteria
Surface luster 1 Luster comparable to enamel
2 Slightly dull, not noticeable from a speaking distance, with some isolated pores
3 Dull surface but acceptable if covered with a film of saliva, multiple pores on more than one-third of the surface
4 Rough surface, cannot be masked by saliva film, simple polishing is not sufficient. Further intervention is necessary. Voids
5 Very rough, unacceptable plaque retentive surface
Staining 1 No surface staining. No marginal staining
2 Minor surface staining, easily removable by polishing, minor marginal staining, and easily removable by polishing
3 Moderate surface staining may also be present on other teeth. Moderate marginal staining, not esthetically unacceptable
4 Unacceptable surface staining on the restoration and major intervention necessary for improvement
5 Severe surface staining and/or subsurface staining, generalized or localized, not accessible for intervention. Deep marginal staining
Color match and translucency 1 Good color match, no difference in shade and/or translucency
2 Minor deviations in shade and/or translucency
3 Distinct deviation but acceptable. Does not affect esthetics, more opaque, more translucent, darker, and brighter
4 Localized clinical deviation that can be corrected by repair. Too opaque, too translucent, too dark, and too bright
5 Unacceptable. Replacement necessary
Esthetic anatomical form 1 Form is ideal
2 Form is only slightly deviated from the normal
3 Form deviates from the normal but is esthetically unacceptable
4 The form is affected and unacceptable esthetically. Intervention is necessary
5 The form is unsatisfactory and/or lost. Repair is not feasible. Replacement needed
Fracture of material and retention 1 No fractures/cracks
2 Small hairline crack
3 Two or larger hairline cracks and/or material chip fractures do not affect the marginal integrity or approximal contact
4 Material chip fractures damage the marginal quality or approximal contacts. Bulk fractures with partial loss (less than half of the restoration)
5 (Partial or complete) loss of restoration or multiple fractures
Marginal adaptation 1 Harmonious outline, no gaps, no white or discolored lines
2 Marginal gap (<150 µm), white lines, small marginal fracture removable by polishing, slight ditching, slight step/flashes, and minor irregularities
3 Gap < 250 µm not removable, several small marginal fractures, major irregularities, ditching, or flash steps
4 Gap > 250 µm or dentin/base exposed, severe ditching or marginal fractures, larger irregularities or steps (repair necessary)
5 Restoration (complete or partial) is loose but in situ, generalized major gaps or irregularities
Radiographic examination 1 No pathology, the harmonious transition between restoration and tooth
2 Acceptable material excess present, positive/negative step present at margin <150 µm
3 Marginal gap < 250 µm, negative steps visible < 250 µm. No adverse effects were noticed, poor radiopacity of filling material
4 Marginal gap >250 µm, material excess accessible; but not removable, negative steps >250 µm, and repairable
5 Secondary caries, large gaps, large overhangs, apical pathology. Fracture/loss of restoration or tooth
Postoperative hypersensitivity 1 No hypersensitivity, normal vitality
2 Minor hypersensitivity for a limited period of time, normal vitality
3 Moderate hypersensitivity, delayed/mild sensitivity; no subjective complaints, no treatment needed
4 Intense hypersensitivity. Delayed with minor subjective symptoms. No clinically detectable sensitivity. Intervention is necessary but not replacement
5 Intense, acute pulpitis or nonvital tooth. Endodontic treatment is necessary and restoration has to be replaced
Recurrence of caries 1 No secondary or primary caries
2 Small and localized demineralization, erosion, or abfraction
3 Larger areas of demineralization, erosion or abrasion/abfraction, dentin not exposed. Only preventive measures are necessary
4 Caries with cavitation and suspected undermining caries, erosion in dentin, and abrasion/abfraction in dentin. Localized and accessible can be repaired
5 Deep caries or exposed dentin that is not accessible for repair or restoration
Oral and general health 1 No oral or general symptoms
2 Minor transient symptoms of short duration; local or generalized
3 Transient symptoms, local and/or general
4 Persisting local or general symptoms of oral contact stomatitis or lichen planus or allergic reactions. Intervention is necessary but no replacement
5 Acute/severe local and/or general symptoms

Calibration Procedures for Clinical Evaluation

The examiners underwent calibration for clinical evaluation and were able to achieve at least 85% intraexaminer agreement. In the event of any disagreement between examiners, a consensus was reached.

Clinical Evaluation

At each recall time (baseline, 6 months, and 12 months), two examiners evaluated the restorations using a standardized evaluation form based on FDI criteria. Out of the 16 criteria available,22 10 criteria were chosen for use in this study (Table 1).

Statistical Analysis

Data were analyzed using Statistical Package for the Social Sciences (SPSS) software, SPSS software (IBM Corp. Released 2012. IBM SPSS Statistics for Windows, version 21.0. Armonk, New York: IBM Corp.) and descriptive statistics were used to describe the distributions of the evaluated criteria. Fisher exact test was employed to analyze the differences in ratings between the two groups at 6 and 12 months. The intention-to-treat protocol was followed for statistical analyses.


The scores achieved at baseline, 6, and 12 months are shown in Table 2. Regardless of the pretreatment liner used, all restorations received a clinical rating of either excellent or good. Out of the 40 participants, only four were lost to follow-up at the 6-month period, and this number did not change at the 12-month follow-up (36 patients).

Table 2: Comparison of clinical evaluation of esthetic, functional, and biological properties of restorations at baseline, 6, and 12 months
Technique PAC pretreatment liner Without pretreatment liner Fisher exact test
FDI criteria Baseline 6 months 12 months Baseline 6 months 12 months p-value
Surface luster
1 40 (100%) 32 (88.9%) 30 (83.3%) 40 (100%) 33 (91.7%) 33 (91.7%)
2 0 4 (11.1%) 6 (16.7%) 0 3 (8.3%) 3 (8.3%) Baseline: NA
3 0 0 0 0 0 0 6 months: 1.00
4 0 0 0 0 0 0 12 months: 0.48
5 0 0 0 0 0 0
1 40 (100%) 32 (88.9%) 28 (77.8%) 40 (100%) 32 (88.9%) 28 (77.8%)
2 0 4 (11.1%) 8 (22.2%) 0 4 (11.1%) 8 (22.2%) Baseline: NA
3 0 0 0 0 0 0 6 months: 1.00
4 0 0 0 0 0 0 12 months: 1.00
5 0 0 0 0 0 0
Color match and translucency
1 38 (94.4%) 32 (88.9%) 31 (86.1%) 38 (94.4%) 32 (88.9%) 32 (88.8%)
2 2 (5.5%) 4 (11.1%) 5 (13.9%) 2 (5.5%) 4 (11.1%) 4 (11.1%) Baseline: 1.00
3 0 0 0 0 0 0 6 months: 1.00
4 0 0 0 0 0 0 12 months: 1.00
5 0 0 0 0 0 0
Esthetic anatomic form
1 36 (91.7%) 33 (91.7%) 31 (86.1%) 36 (91.7%) 33 (91.7%) 31 (86.1%)
2 4 (8.3%) 3 (8.3%) 5 (13.9%) 4 (8.3%) 3 (8.3%) 5 (13.9%) Baseline: 0.67
3 0 0 0 0 0 0 6 months: 1.00
4 0 0 0 0 0 0 12 months: 1.00
5 0 0 0 0 0 0
Fracture of material and retention
1 40 (100%) 36 (100%) 36 (100%) 40 (100%) 36 (100%) 36 (100%)
2 0 0 0 0 0 0 Baseline: NA
3 0 0 0 0 0 0 6 months: NA
4 0 0 0 0 0 0 12 months: NA
5 0 0 0 0 0 0
Marginal adaptation
1 40 (100%) 36 (100%) 36 (100%) 40 (100%) 34 (94.4%) 34 (94.4%)
2 0 0 0 0 2 (5.6%) 2 (5.6%) Baseline: NA
3 0 0 0 0 0 0 6 months: 0.49 (NS)
4 0 0 0 0 0 0 12 months: 0.49 (NS)
5 0 0 0 0 0 0
Radiographic examination
1 40 (100%) 36 (100%) 36 (100%) 40 (100%) 36 (100%) 36 (100%)
2 0 0 0 0 0 0 Baseline: NA
3 0 0 0 0 0 0 6 months: NA
4 0 0 0 0 0 0 12 months: NA
5 0 0 0 0 0 0
Postoperative sensitivity
1 40 (100%) 36 (100%) 36 (100%) 40 (100%) 36 (100%) 36 (100%)
2 0 0 0 0 0 0 Baseline: NA
3 0 0 0 0 0 0 6 months: NA
4 0 0 0 0 0 0 12 months: NA
5 0 0 0 0 0 0
Recurrence of caries
1 40 (100%) 36 (100%) 36 (100%) 40 (100%) 36 (100%) 36 (100%)
2 0 0 0 0 0 0 Baseline: NA
3 0 0 0 0 0 0 6 months: NA
4 0 0 0 0 0 0 12 months: NA
5 0 0 0 0 0 0
Oral and general health
1 40 (100%) 36 (100%) 36 (100%) 40 (100%) 36 (100%) 36 (100%)
2 0 0 0 0 0 0 Baseline: NA
3 0 0 0 0 0 0 6 months: NA
4 0 0 0 0 0 0 12 months: NA
5 0 0 0 0 0 0

NA, not applicable

Surface Luster

Following baseline assessments, all restorations in test and control groups demonstrated excellent surface luster, as per clinical standards. Upon 6-month evaluation, the test group had 88.1% (32 restorations) rated as excellent, with the remaining 11.1% (4) classified as clinically good. In comparison, the control group had 91.7% (33 restorations) rated as excellent and 8.3% (3) considered clinically good. After 12 months, the test group had 83.3% (30) rated as excellent, and the remaining 16.7% rated as clinically good. The control group had 91.7% (33) rated as excellent, and 8.3% rated as clinically good. The two groups did not differ significantly in terms of restoration quality at either the 6- or 12-month follow-up evaluations.

Color Match and Translucency

The initial assessment revealed that both groups had 94.4% (34) restorations that were evaluated as excellent for color match and translucency, with the remaining 5.6% (4) scored as good. After 6 months, the test group and control group exhibited 88.9% (32) restorations that were scored as excellent, while 11.1% (4) were clinically good. Following the 12-month mark, the test group demonstrated 86.1% (28) excellent restorations and 13.9% (8) clinically good restorations. However, the control group maintained the same level of excellence as it did after the 6-month evaluation.


At the 6-month recall, 11.1% (four restorations) of the restorations exhibited minor surface staining, and this increased to 22.2% at the 12-month recall. No statistically significant difference in staining was observed between the groups at either time point.

Esthetic Anatomic Form

At baseline, the test group had 33 restorations (91.7%) with an excellent score and three restorations (8.3%) with a good score. The control group had 34 restorations (94.4%) with an excellent score and two restorations (5.6%) with an acceptable anatomic form. After 6 months, both groups showed that 91.7% (33 restorations) were excellent, and 8.3% (three restorations) were clinically good. After 12 months, both groups I and II showed that 86.1% (31 restorations) were excellent, and 13.9% (five restorations) were clinically good.

Fracture of Material and Retention

All restorations in both groups remained intact at the 6- and 12-month follow-up periods.

Marginal Adaptation

In this criteria, the test group showed excellent marginal adaptation for all restorations at baseline, 6, and 12 months. In the control group, at the 6- and 12-month recalls, two restorations showed some discrepancies in marginal adaptation. No significant difference was detected between the two groups at both the 6- and 12-month recall for marginal adaptation.

Postoperative Sensitivity, Caries, and Others

There was no postoperative sensitivity observed in any of the restorations immediately after the procedure and during the 6- and 12-month follow-up periods. Furthermore, both groups did not exhibit any recurrence of caries during the baseline, 6, and 12 month periods. Clinically, all the restorations in both groups were deemed excellent in terms of oral and general health, radiographic examination, and during all the follow-up periods.


In this split-mouth RCT, the clinical performance and longevity of composite restorations with PAC pretreatment liner were evaluated using the FDI criteria as the primary assessment tool. Composite restorations are preferred in contemporary restorative dentistry due to their minimal invasiveness and esthetic benefits. However, the long-term success of these restorations remains a topic of debate, as collagen within these restorations is susceptible to MMPs, resulting in the breakdown of the hybrid layer, and compromising the bond between the resin and dentin. Therefore, there is a need to enhance the efficacy and longevity of these restorations. One such strategy is the biomodification of dentin with PAC, a natural agent known for its antioxidant, cross-linking, and protease-inhibitory properties.23,24

Literature suggests that PAC interacts with collagen and can improve the clinical performance of composite restorations, making it an effective option for enhancing restoration durability.17,25 Therefore, the present study was done to shed light on whether PAC pretreatment can improve the clinical outcomes of posterior composite restorations. The null hypothesis was accepted, as there was a lack of statistical significance between the control and test groups.

The selection of a 2% concentration of PAC solution was guided by the need to strike a balance between achieving a concentration that could potentially exhibit favorable bonding properties while avoiding potential negative effects.26 Previous studies25,27 investigating the impact of PAC on adhesive bonding have explored concentrations ranging from 1 to 3%, with varying outcomes. Our choice of 2% concentration was based on the aim to provide sufficient cross-linking while maintaining safety and efficacy.27

The interventions were performed with great attention to detail to ensure consistency and reliability. A wide range of outcome measures was evaluated, encompassing the restorations’ functional, biological, and esthetic aspects. Our findings indicate that both groups exhibited excellent clinical outcomes across multiple parameters with and without PAC pretreatment. Surface luster, color match, translucency, and marginal adaptation, crucial indicators of restoration integrity, were consistently rated as “excellent” or “good” in both groups at baseline, 6, and 12 months. This suggests that the quality of restorations in both groups was highly satisfactory from an esthetic and functional perspective.

One of the noteworthy findings of the present study was the minimal staining observed in both groups throughout the evaluation periods. Discoloration of restorations can significantly affect patient satisfaction and the overall esthetic result. Results of the present study indicate that pretreatment with PAC did not influence the susceptibility of composite restorations to staining. This is a positive outcome, as staining can be a significant concern for patients seeking dental restorations.

Marginal adaptation, a critical indicator of restoration integrity, was maintained at high levels in both groups during the study. This was a crucial finding as inadequate marginal adaptation can lead to issues such as microleakage and recurrent caries.28 Results of the present study suggest that the application of PAC as a pretreatment liner did not compromise the marginal adaptation of the restorations. The study conducted by De Souza et al.,25 found a higher incidence of marginal discoloration in restorations after 6 and 24 months in the 5% PAC group, which is contrary to present study findings.

Another important aspect of our study was the evaluation of postoperative sensitivity and the occurrence of recurrent caries. Postoperative sensitivity is a common concern for patients undergoing dental restorations, and the prevention of recurrent caries is essential for the long-term success of restorations.29 Importantly, neither group in the present study exhibited postoperative sensitivity or recurrent caries during the baseline, 6, and 12 month follow-up periods. This indicates that the use of PAC as a pretreatment liner did not compromise the postoperative outcomes of the restorations.

The general and oral health assessments and radiographic examinations revealed no concerning findings during all follow-up periods. The results of the present study demonstrate that both groups, with and without PAC pretreatment, exhibited highly reliable and effective restorations and support the use of PAC as a liner for posterior composite restorations in clinical practice.

It’s important to acknowledge that further research and validation are needed to fully explore the potential of PAC in restorative dentistry. The clinical study’s limitations include the need for a follow-up period of at least 2 years for direct composite restorations to show noticeable clinical changes.


A 2% PAC pretreatment enhances the clinical durability of posterior composite restorations and contributes to excellent clinical outcomes, including esthetic, functional, and biological aspects. This innovative approach offers promising results for improving longevity and clinical performance for dental restorations.


Lakshmi C Padarthi https://orcid.org/0009-0006-1379-3371

Lavanya Anumula https://orcid.org/0000-0002-0930-8445

Suneel K Chinni https://orcid.org/0000-0002-2668-2316

Swapna Sannapureddy https://orcid.org/0000-0002-6363-8242

Kiranmayi Govula https://orcid.org/0000-0001-8106-7634

Sindhu Ramesh https://orcid.org/0000-0001-8022-2815


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