Evaluation of Post-Cementation Sensitivity After Cementation with Bio-Active Luting Cement - A Randomized Clinical Control Trial

Introduction

The most common complaint following cementation is the occurrence of post cementation sensitivity. Many reasons have been attributed for post cementation sensitivity which includes amount of tooth preparation, type of cement, low initial pH of set cement, occlusal discrepancies, and smear layer removal. The sensitivity to cold stimulus after cementation can be indicative of a gap present under crown or a marginal gap connecting to opened tubules in the dentin. A pulp fluid outflow occurs as a result of the contraction of dentinal fluid in this gap, which causes postoperative sensitivity.¹ Thus, the dental luting cement should function as a barrier to prevent the leakage of microorganisms by providing optimum seal between the tooth and restoration.

Over the last decade, several modifications and improvements have been incorporated in the luting cements for enhancing their mechanical, physical and biological properties. The addition of bioactive glass in the luting cement has been newly introduced.

The ability to connect with living tissue or systems is referred to as bioactive.² Giomer is a dental luting agent made of resin that releases fluoride and has PRG (Prereacted Glass Ionomer) fillers. The bioactive glass that is incorporated in Giomer has the capacity to release certain beneficial ions upon contact with the biological fluids. These ions include fluoride and calcium that help in the developing of apatite crystals.³ Upon usage of bioactive luting cement, the ions that are released include sodium, which influence the function of other ions, borate which has bactericidal activity, helps in promotion of bone formation as well as prevention of bacterial adhesion, bone calcification is facilitated by silicate, aluminum, which aids in reducing sensitivity, strontium a buffering agent that neutralizes acids, formation of bone tissue, calcification, increased acid resistance, fluoride's antibacterial and caries-preventive effects, and production of acid-insoluble fluoroapatite crystals. Thus, Giomer is a specialized material that combines the properties of glass ionomer and composite based cements. The PRG technology incorporated in the cement not only provides the benefits of mechanical strength of composite material, but also releases various ions that aid in multiple biological functions.⁴

This study aimed to evaluate the post-cementation sensitivity after cementation with bio-active luting cement in a randomized clinical control trial, using resin modified glass ionomer cement as control.

Materials and Methods

The study was carried out in the Department of Prosthodontics at a Dental college, South India. It was approved by the Institutional Review Board under the reference number BDC/Exam/509/2019-20 and was carried out in accordance with the instructions of the institutional ethical committee and the Helsinky declaration of 1975, as revised in 2000. The sample size was calculated using an online sample size calculator, with the following formula.⁵

Where

• nA is calculated sample size

• k is the matching ratio=1

• σ is standard deviation = 0.22

• μ is expected mean (μA = 0.05& μB = 0.4) α is Type I error = 5%

• β is Type II error, meaning 1−β is power = 80%

The sample size was determined to be 24. Thus in each treatment group, a sample size of 12 was considered.

The participants were selected from those seeking oral rehabilitation in Department of Prosthodontics at a Dental college in South India. Appropriate medical and dental history of each patient was recorded, after which clinical examination was conducted. Patients meeting the inclusion criteria gave their formally signed consent. Split mouth design with a quadrant as the unit was used for the study. One quadrant was randomly allocated using simple stratified randomization for control group. Other quadrant was randomly allocated using simple stratified randomization for experimental group. Group allocation was double blinded.

Participants were chosen based on their fulfilment of the inclusion criteria.

Inclusion criteria⁶

1. Patients in the age group of 21 to 45 years.

2. Patients requiring crown and bridge prosthesis placement in relation to posterior maxillary or mandibular second premolar and second molar region.

3. Patients with satisfactory oral hygiene (Index- Simplified Oral Hygiene Index by Greene and Vermilion- 1964).

4. Reliable and co-operative patients.

5. Patients with absence of fresh post extraction wound or traumatic wound.

Exclusion criteria⁶

1. Non- vital teeth

2. Patients who have previously experienced sensitivity in the abutment teeth

3. Subgingival caries

4. Abrasion/erosion/ teeth with attrition,

5. Frequent dentinal sensitivity

6. Patients undergoing immunosuppressive therapy and radiation

7. Class V non-caries lesions on teeth

8. Restored teeth

9. Prominent periodontal pockets

10. Endodontic/Periodontal infections

11. Patients with bone associated diseases and malignant diseases

12. Patients with personal habits such as alcohol consumption, drug usage and smoking

13. Poor oral hygiene

Total 24 crown and bridge abutments were cemented. The test group had 12 crowns luted with bioactive luting cement (BeautiCem SA- Giomer, Shofu) and the control group had 12 crowns luted with resin modified glass ionomer luting cement (RMGIC) (Relyx Luting 2- 3M ESPE).

Standardization of abutment tooth

Only second premolars and molars on either the maxilla or the mandible were selected as abutments (Figure 1 and 2)

Standardization of tooth preparation

Abutments were prepared with equi-gingival finish line following standardized reduction protocol under the guidance of an experienced clinician. (Figure 3 and 4)

Standardization of crowns

Following tooth preparation, the abutment teeth were temporized using temporary crown and bridge material and the temporary bridges were luted (Figure 5). Metal try in of the PFM crowns were verified intra-orally (Figure 6). Only Porcelain fused to metal (PFM) crowns were luted (Figure 7).

The right and left lateral occlusal view can be seen in figure 8 a and b

Figures 9 and 10 show the bioactive and RMGIC luting cement that were utilized for the study

Pre-cementation sensitivity data collection

Before cementation, the pre-cementation sensitivity was recorded by means of the following tests:

1. Cold water test: A 5 mL syringe was used to irrigate the tooth for five seconds with ice cold water, and the test discontinued as soon as the subject complained of pain.

2. Compressed air test: Using an air water syringe, a stream of 90 psi compressed air was applied for ten seconds to the tooth's lingual and facial surfaces.

3. Biting pressure test: The patient was asked to bite firmly on the end of ice cream stick in to check the sensitivity on biting.

Sensitivity evaluation

Sensitivity was evaluated with the help of Schiff Scale (0–3) which was given by Schiff et al. in 1994 (Table 1).

Post-cementation sensitivity data collection

Post cementation sensitivity was recorded using the same measurement method at baseline, one week and three months following cementation (Figure 11)

Statistical methods

The data obtained from the tests was subjected to statistical analysis. For data analysis, difference of mean between groups was measured using independent test and difference of mean within groups at different time intervals was measured using ANOVA test of significance and Turkey’s Post hoc analysis. The significance level for the study was set at 0.05. Statistical significance was defined as 0.05 or less.

A total of 24 crown and bridge abutments were cemented. Twelve crown and bridge abutments were cemented using bioactive luting cement, and the remaining twelve were cemented using resin-modified glass ionomer luting cement. Group 1 comprised of three males and three females with a mean age of 36.6 ± 4.08 years.

Group 2 comprised of three males and three females with mean age of 36.6 ± 4.08 years. Table 1a represents the intragroup comparison of the post cementation sensitivity at baseline, one week and three months after cementation with bioactive luting cement (Group I) by implying cold water test while table 1b represents the intragroup comparison of the post cementation sensitivity at baseline, one week and three months after cementation with resin modified GIC (Group II) by implying cold water test.

Table 2 shows the inter-group comparison of Group 1 and Group II with respect to the sensitivity seen at different time intervals on performing the cold water test.

Table 3a shows intragroup comparison of the post cementation sensitivity at baseline, one week and three months after cementation with bioactive luting cement (Group I) using air test while Table 3b shows the intragroup comparison of the post cementation sensitivity at baseline, one week and three months after cementation with resin modified GIC luting cement (Group II) using air test.

Table 4 shows inter-group comparison of Group 1 and Group II with respect to the sensitivity seen at different time intervals on performing the compressed air test.

Table 5a shows intragroup comparison of the post cementation sensitivity at baseline, one week and three months after cementation with bioactive luting cement (Group I) using biting pressure test while table 5b shows intragroup comparison of the post cementation sensitivity at baseline, one week and three months after cementation with resin modified GIC (Group II) using biting pressure test.

Table 6 shows inter-group comparison of Group 1 and Group II with respect to the sensitivity seen at different time intervals on performing the biting pressure test.

Discussion

Any substance used to affix or cement indirect restorations to ready teeth is referred to as a luting agent in the Glossary of Prosthodontic Terms (GPT-9). This study compared newly developed bioactive luting cement with the resin modified glass ionomer cement. In 2000, Giomers, a new hybrid material containing both the glass ionomer content and composite was introduced. This new group of cement overcame the disadvantages of compomer with a stable fluoride releasing capacity. Giomer was a pre-reacted glass ionomer filler-filled resin composite system. When these fillers are released and recharged with fluoride, they produce a bioactive effect. Thus, it combines the biological properties of glass ionomer and mechanical properties of composite resin.^3,4

RMGIC was introduced by Antonucci et al. in 1988. This cement was used to overcome the problems associated with conventional glass ionomer cement. They are also a hybrid of GIC and resin composite. But, in this cement, a dimethacrylate monomer, Hydroxyethyl methacrylate (HEMA) is grafted in polyacrylic acid. Thus, GIC forms the base component of this cement, whereas in Giomer the resin composite forms the base component.⁸

Dentin hypersensitivity

At International Workshop of Dentine Hypersensitivity in 1983, the term dentine hypersensitivity (DHS) was defined as a frequently experienced dental complication. When dentin is exposed to various stimuli like thermal, evaporative, tactile, chemical or osmotic, it causes a short, sharp pain in exposed dentine. This is unrelated to any other dental issues or pathologies.

Dentin hypersensitivity can be assessed using a method known as stimulus-based assessment, which measures the intensity of the stimulus needed to cause pain, or response-based assessment, which measures the subjective intensity of the pain brought on by a specific stimulus.⁹

According to a study by Rocha MOC et al., where the sensitivity and specificity of various assessment scales for dentin hypersensitivity were compared, the highest specificity of 91% was noted for Schiff scale. They stated that the Schiff scale was the preferred one for assessment of dentin hypersensitivity. Thus, Schiff scale was utilised in this study to assess the degree of dentinal hypersensitivity on a scale of 0-3.¹⁰

In the present study, no significant difference was observed between the two cements at pre-cementation stage which was similar to the study by V Chandrasekar.¹¹

The sensitivity scores were found to have reduced from pre-cementation to three months after cementation with both the cements in all the tests. This was also noted to be similar to the results obtained in the study by V Chandrasekar.¹¹

Long term clinical evaluation is required in the future to understand the clinical performance of bio-active luting cement.

Conclusion

The following conclusions can be drawn from the study's limitations and the data collected:

• Almost all the patients responded to hypersensitivity at pre-cementation and baseline with cold water, compressed air and biting pressure tests.

• The sensitivity scores reduced over time for both the luting agents.

• Based on the results, it can be concluded that the bioactive luting cement exhibited lesser sensitivity scores when compared to resin modified GIC luting cement.

Thus considering the lower sensitivity scores, bioactive luting cement can serve as an effective alternate choice of material for luting compared to RMGIC.