Effect of Different Heating Protocols of Resin Composites on Pulp Condition (Randomized Controlled Trial)

This randomized controlled clinical trial evaluates the effect of different resin composite preheating protocols on pulpal inflammation and postoperative pain. Thirty patients with deep occlusal carious lesions (ICDAS scores 5 and 6) will be randomly assigned to three equal groups (n=10). Group I will receive thermoviscous bulk-fill composite (VisCalor, VOCO) preheated to 65°C and placed as a single 4-mm increment. Group II will receive conventional nanohybrid composite (Ivoclar Vivadent) preheated to 55°C and placed incrementally. Group III (control) will receive the same composite at room temperature (23°C) using incremental placement. Gingival crevicular fluid (GCF) samples will be collected at baseline, immediately post-treatment, and at 7-day follow-up. Tumor necrosis factor-alpha (TNF-α) concentrations will be quantified using ELISA. Postoperative pain will be assessed using the Visual Analog Scale (VAS) at baseline and day 7. The study aims to determine whether different preheating protocols differentially affect pulpal inflammatory status and whether GCF TNF-α correlates with postoperative pain.

Study Overview

• Status: Completed
• Conditions: Postoperative Pain; Dental Caries; Pulpal Inflammation
• Intervention / Treatment: Device: Arm 1 only "VisCalor Thermoviscous Bulk-Fill Composite"; Device: Tetric EvoCeram Conventional Nanohybrid Composite (Preheated 55°C); Device: Tetric EvoCeram Conventional Nanohybrid Composite (Room Temperature)

Detailed Description

1. Background and Rationale Pre-heating of resin-based composites decreases viscosity, enhances flow characteristics, and improves monomer conversion rates [1,2]. Specialized devices including the VisCalor delivery system have been introduced to standardize prewarming methodologies [3,4]. However, the utilization of preheated substances in deep preparations raises legitimate thermal concerns for the pulp-dentin interface. Zach and Cohen [5] demonstrated that a 5.5°C elevation in pulpal temperature induces irreversible pulpitis or necrosis in 15% of teeth.

   Cytokines represent pivotal inflammatory mediators and have been examined in gingival crevicular fluid (GCF) as diagnostic markers of pulpal inflammation [6,7]. Tumor necrosis factor-alpha (TNF-α) functions as a pleiotropic pro-inflammatory cytokine central to initiating and amplifying pulpal inflammatory cascades [8,9]. Celik et al. [10] established that diverse restorative materials significantly influence GCF concentrations of IL-6, IL-8, and TNF-α, demonstrating material-specific temporal variations.

   Despite accumulating evidence, no clinical investigation has evaluated varying preheating protocols on pulpal inflammatory status utilizing objective biomarkers. Consequently, this randomized controlled study aims to examine the influence of different prewarming regimens on pulpal inflammatory status through GCF TNF-α quantification and VAS pain assessment.

2. Study Design This is a randomized, single-blinded, parallel-group controlled clinical trial conducted at the outpatient facility of the Faculty of Dentistry, Ain Shams University. The study adheres to the Consolidated Standards of Reporting Trials (CONSORT) guidelines [11]. Ethical approval was obtained from the Research Ethics Committee of the Faculty of Dentistry, Ain Shams University (approval number: [to be inserted]), and the study is performed in accordance with the Declaration of Helsinki [12]. Written informed consent is secured from all participants.

3. Eligibility Criteria

   Inclusion Criteria:

   Patients aged 18-45 years in good general health

   Asymptomatic deep occlusal carious lesions with ICDAS scores 5 and 6, confirmed by preoperative periapical radiographs

   Healthy gingiva with probing depths ≤ 3 mm, normal occlusion, and no radiographic evidence of periodontal bone loss

   No anti-inflammatory or antibiotic therapy within the preceding six months

   Willingness to complete the full trial period with signed informed consent

   Exclusion Criteria:

   Vulnerable populations (pregnant or nursing women, incarcerated individuals, those with mental health disorders)

   Current tobacco users

   Patients with systemic conditions (e.g., diabetes mellitus, immunocompromise)

   Teeth with prior endodontic intervention

   Periodontal pockets >3 mm

   Use of medications influencing inflammatory responses

   Orthodontic appliance wearers

4. Interventions Group I (Test Group 1): Thermoviscous bulk-fill composite (VisCalor, VOCO, Germany) preheated to 65°C using VisCalor Dispenser, placed as a single bulk increment (4 mm thickness).

   Group II (Test Group 2): Conventional nanohybrid composite (Ivoclar Vivadent, Liechtenstein) preheated to 55°C using Composite Heater (Cicada Dental, China), placed incrementally (2 mm thickness per increment).

   Group III (Control Group): Conventional nanohybrid composite (Ivoclar Vivadent, Liechtenstein) at room temperature (23°C), placed incrementally (2 mm thickness per increment).

   All restorations are performed by a single operator. Selective enamel etching combined with universal bonding (Bisco) is applied across all groups following manufacturer specifications. Cavity preparations are executed with diamond burs in a high-speed handpiece under continuous water coolant.

5. Outcome Measures

   Primary Outcome:

   Pulpal inflammatory response assessed by GCF TNF-α levels (pg/mL) at baseline, immediately post-treatment, and 7 days post-treatment, measured using ELISA [10].

   Secondary Outcomes:

   Postoperative pain assessed using Visual Analog Scale (VAS) at baseline and 7 days post-treatment

   Correlation between TNF-α levels and pain scores

6. Sample Size and Power Sample size was calculated using G*Power software version 3.1.9.7 (Heinrich Heine University, Dusseldorf, Germany) [13] based on prior investigations [10]. The minimally acceptable sample size was 5 per group, calculated from the mean ± standard deviation of TNF-α levels pre-restoration (5.83 ± 0.25) and post-restoration (7.15 ± 0.7), yielding a 2.8 effect size. With power set at 95% and type I error probability at 0.05, the sample size was increased to 10 per group to enhance statistical power and accommodate anticipated attrition. Consequently, 30 patients (10 per group) are enrolled.
7. Statistical Analysis The normality of data distribution and homogeneity of variances are verified using Shapiro-Wilk's test. Intergroup comparisons are performed using Kruskal-Wallis test with Dunn's post-hoc correction. Intragroup temporal changes are analyzed using Friedman test with Nemenyi post-hoc analysis. Baseline versus 7-day comparisons utilize Wilcoxon signed-rank test. Correlation between TNF-α and pain scores is assessed using Spearman's rank correlation coefficient. Significance is established at p < 0.05. Calculations are performed using SPSS software version 26.0 (IBM, NY, USA) and R statistical software.
8. Study Timeline Phase Duration Description Screening 1 week Medical history, clinical examination, radiographs, eligibility confirmation Baseline Day 0 Informed consent, demographic data, baseline VAS, baseline GCF collection Intervention Day 0 Anesthesia, rubber dam, cavity preparation, composite placement, light curing Immediate Post-op Day 0 Immediate GCF collection (T1) Follow-up Day 7 Clinical examination, VAS, GCF collection Data Analysis 2-4 weeks ELISA analysis, statistical analysis
9. Data Management All data are entered into a password-protected Excel spreadsheet. Patient identification is coded (e.g., G1_P01 for Group I, Patient 1). A separate master linking file (password-protected) maintains codes linked to patient identities. Data are backed up weekly to an external encrypted hard drive. All records are retained for five years following publication of study results.
10. Safety and Adverse Events This study uses commercially available dental materials with established safety profiles. Participants are closely monitored throughout the follow-up period. Any patient who discontinues follow-up or undergoes extraction of the involved tooth is excluded from the final analysis. Patients experiencing persistent or severe postoperative pain receive appropriate clinical management.
11. Dissemination of Results Results will be published in a peer-reviewed journal (BMC Oral Health) and presented at national and international conferences.

References for Detailed Description Daronch M, Rueggeberg FA, De Goes MF, Giudici R. Polymerization kinetics of pre-heated composite. J Dent Res. 2006;85(1):38-43.

Lovell LG, Newman SM, Bowman CN. The effects of light intensity, temperature, and comonomer composition on the polymerization behavior of dimethacrylate dental resins. J Dent Res. 1999;78(8):1469-76.

Ates H, Iscan Yapar M. The effect of different preheating methods on the intrapulpal temperature of bulk-fill composite resins. BMC Oral Health. 2025;25(1):1977.

El-Saeed AS, Elerian FA, Hamama HH, Mahmoud SH. Impact of resin composite restorative material pre-heating on dental pulp temperature: A laboratory study. Mansoura J Dent. 2022;9(3):128-32.

Zach L, Cohen G. Pulp response to externally applied heat. Oral Surg Oral Med Oral Pathol. 1965;19(4):515-30.

Champagne CM, Buchanan W, Reddy MS, Preisser JS, Beck JD, Offenbacher S. Potential for gingival crevice fluid measures as predictors of risk for periodontal diseases. Periodontol 2000. 2003;31:167-80.

Lamster IB, Hartley LJ, Vogel RI. Development of a biological profile for gingival crevicular fluid. J Periodontol. 1985;56(Special Issue):13-21.

Pezelj-Ribaric S, Anic I, Brekalo I, Miletic I, Hasan M, Simunovic-Soskie M. Detection of tumor necrosis factor alpha in normal and inflamed human dental pulps. Arch Med Res. 2002;33(5):482-4.

Kokkas AB, Goulas A, Varsamidis K, Mirtsou V, Tziafas D. Irreversible but not reversible pulpitis is associated with up-regulation of tumour necrosis factor-alpha gene expression in human pulp. Int Endod J. 2007;40(3):198-203.

Celik N, Askin S, Gul MA, Seven N. The effect of restorative materials on cytokines in gingival crevicular fluid. Arch Oral Biol. 2017;84:139-44.

Moher D, Hopewell S, Schulz KF, Montori V, Gøtzsche PC, Devereaux PJ, et al. CONSORT 2010 explanation and elaboration: updated guidelines for reporting parallel group randomised trials. Int J Surg. 2012;10(1):28-55.

World Medical Association. World Medical Association Declaration of Helsinki: Ethical principles for medical research involving human subjects. JAMA. 2013;310(20):2191-4.

Faul F, Erdfelder E, Buchner A, Lang AG. Statistical power analyses using G*Power 3.1: tests for correlation and regression analyses. Behav Res Methods. 2009;41(4):1149-60.

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Cairo Governorate
    • Cairo, Cairo Governorate, Egypt
      • Ain Shams University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

Patients aged 18-45 years in good general health

Asymptomatic deep occlusal carious lesions with ICDAS scores 5 and 6, confirmed by preoperative periapical radiographs

Healthy gingiva with probing depths ≤ 3 mm

Normal occlusion

No radiographic evidence of periodontal bone loss

No anti-inflammatory or antibiotic therapy within the preceding six months

Willingness to provide written informed consent and complete the full study period

Exclusion Criteria:

Pregnant or nursing women

Incarcerated individuals

Individuals with mental health disorders

Current tobacco users

Patients with systemic conditions (e.g., diabetes mellitus, immunocompromise)

Teeth with prior endodontic therapy

Periodontal pockets >3 mm

Use of medications influencing inflammatory responses

Orthodontic appliance wearers

History of allergy to dental materials or local anesthetics

Active periodontal disease

Teeth with periapical pathology or pulp exposure

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Thermoviscous Bulk-Fill Composite - VisCalor (65°C); Participants in this arm will receive deep Class I restorations using thermoviscous bulk-fill composite (VisCalor, VOCO, Germany) preheated to 65°C using the VisCalor Dispenser. The composite is placed as a single 4-mm bulk increment and light-cured according to the manufacturer's instructions. GCF samples are collected at baseline, immediately post-treatment, and at 7-day follow-up for TNF-α quantification. Pain is assessed using VAS at baseline and day 7.	Device: Arm 1 only "VisCalor Thermoviscous Bulk-Fill Composite"; VisCalor (VOCO, Germany) is a thermoviscous bulk-fill composite resin designed for posterior restorations. It is supplied in compules and preheated to 65°C using the VisCalor Dispenser, which maintains the material at the target temperature until the moment of application. The composite has 89% filled universal nano-hybrid composition and is placed as a single 4-mm bulk increment.
Experimental: Preheated Conventional Nanohybrid Composite - 55°C; Participants in this arm will receive deep Class I restorations using conventional nanohybrid composite (Tetric EvoCeram, Ivoclar Vivadent, Liechtenstein) preheated to 55°C using a Composite Heater (Cicada Dental, China). The composite is placed incrementally in 2-mm layers and light-cured according to the manufacturer's instructions. GCF samples are collected at baseline, immediately post-treatment, and at 7-day follow-up for TNF-α quantification. Pain is assessed using VAS at baseline and day 7.	Device: Tetric EvoCeram Conventional Nanohybrid Composite (Preheated 55°C); Tetric EvoCeram (Ivoclar Vivadent, Liechtenstein) is a conventional nanohybrid composite resin with 76 wt.% filler content (barium glass, ytterbium trifluoride, silicon dioxide, mixed oxide). It is preheated to 55°C using a Composite Heater (Cicada Dental, China) for 5 minutes and placed incrementally in 2-mm layers. Each increment is light-cured for 20 seconds.
Experimental: Conventional Nanohybrid Composite - Room Temperature (Control); Participants in this arm will receive deep Class I restorations using conventional nanohybrid composite (Tetric EvoCeram, Ivoclar Vivadent, Liechtenstein) at room temperature (23°C) with no preheating. The composite is placed incrementally in 2-mm layers and light-cured according to the manufacturer's instructions. This arm serves as the control group. GCF samples are collected at baseline, immediately post-treatment, and at 7-day follow-up for TNF-α quantification. Pain is assessed using VAS at baseline and day 7.	Device: Tetric EvoCeram Conventional Nanohybrid Composite (Room Temperature); Tetric EvoCeram (Ivoclar Vivadent, Liechtenstein) is a conventional nanohybrid composite resin with 76 wt.% filler content (barium glass, ytterbium trifluoride, silicon dioxide, mixed oxide). It is used at room temperature (23°C) without preheating and placed incrementally in 2-mm layers. Each increment is light-cured for 20 seconds. This is the control intervention.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pulpal Inflammatory Response Assessed by Gingival Crevicular Fluid TNF-α Levels	Changes in tumor necrosis factor-alpha (TNF-α) concentrations in gingival crevicular fluid (GCF) measured at three time points: baseline (pre-treatment), immediately post-restoration, and 7 days post-restoration. TNF-α is a key pro-inflammatory cytokine that reflects pulpal inflammatory status.	Baseline (pre-treatment), immediately after restoration, and 7 days post-restoration

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postoperative Pain Assessed by Visual Analog Scale (VAS)	Changes in postoperative pain intensity measured using the Visual Analog Scale (VAS). Patients indicate their pain level on a 10 cm horizontal line (0 = no pain, 10 = worst imaginable pain). Pain scores are recorded at baseline and 7 days post-treatment	Baseline (pre-treatment) and 7 days post-restoration

Collaborators and Investigators

• Sponsor: Ain Shams University

Publications and helpful links

General Publications

• Tauböck TT, Tarle Z, Marovic D, Attin T, Attin R. Pre-heating of resin composites: Effects on conversion, mechanical properties and polymerization shrinkage. Dent Mater. 2015;31(8):895-902.
• Dawson VS, Amjad S, Fransson H. Endodontic complications in teeth with vital pulps restored with composite resins: a systematic review. Int Endod J. 2015 Jul;48(7):627-38. doi: 10.1111/iej.12364. Epub 2014 Sep 12.
• Morrison JI, Borg P, Simon A. Plasticity and recovery of skeletal muscle satellite cells during limb regeneration. FASEB J. 2010 Mar;24(3):750-6. doi: 10.1096/fj.09-134825. Epub 2009 Nov 3.
• Pezelj-Ribaric S, Anic I, Brekalo I, Miletic I, Hasan M, Simunovic-Soskic M. Detection of tumor necrosis factor alpha in normal and inflamed human dental pulps. Arch Med Res. 2002 Sep-Oct;33(5):482-4. doi: 10.1016/s0188-4409(02)00396-x.
• ZACH L, COHEN G. PULP RESPONSE TO EXTERNALLY APPLIED HEAT. Oral Surg Oral Med Oral Pathol. 1965 Apr;19:515-30. doi: 10.1016/0030-4220(65)90015-0. No abstract available.
• Celik N, Askin S, Gul MA, Seven N. The effect of restorative materials on cytokines in gingival crevicular fluid. Arch Oral Biol. 2017 Dec;84:139-144. doi: 10.1016/j.archoralbio.2017.09.026. Epub 2017 Sep 27.

Helpful Links

• The official website of the Faculty of Dentistry, Ain Shams University, where the study was conducted.
• The CONSORT guidelines used for reporting this randomized controlled trial.
• The ethical guidelines followed in conducting this study.

Study record dates

Study Major Dates

• Study Start (Actual): November 1, 2025
• Primary Completion (Actual): May 30, 2026
• Study Completion (Actual): June 30, 2026

Study Registration Dates

• First Submitted: July 18, 2026
• First Submitted That Met QC Criteria: July 18, 2026
• First Posted (Actual): July 22, 2026

Study Record Updates

• Last Update Posted (Actual): July 22, 2026
• Last Update Submitted That Met QC Criteria: July 18, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Randomized controlled trial; VAS; Postoperative pain; Gingival crevicular fluid; Endodontics; TNF-α; ICDAS; GCF; Dental restoration; Pulpal inflammation; Deep carious lesions; Pre-heated composites; Resin composite preheating; Incremental composite placement; Cytokine biomarkers; VisCalor; Pulp-dentin complex
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Stomatognathic Diseases; Postoperative Complications; Pathologic Processes; Tooth Diseases; Tooth Demineralization; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative; Dental Caries
• Other Study ID Numbers: FDASU-Rec IM012564

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared. The datasets generated and analyzed during the current study are available from the corresponding author on reasonable request, subject to institutional review board approval and participant consent restrictions. Due to the small sample size and the single-center nature of this MSc thesis study, sharing de-identified individual participant data could potentially compromise participant confidentiality despite de-identification efforts. Therefore, data will only be shared in aggregate form as presented in the manuscript and accompanying tables and figures.

Study Data/Documents

1. Study Protocol
   Information identifier: Amira Adel Mohamed Hassan
   Information comments: Complete study protocol including study design, methodology, intervention details, outcome measures, and statistical analysis plan.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No