Comparative evaluation of novel customized cushees during rubber dam isolation using self-designed evaluation criteria: A randomized clinical study.

BACKGROUND: Rubber dam plays essential role in dentistry and various modifications have been done to improve patients acceptance and to eliminate the discomfort caused due to clamps. AIM: Clinical evaluation of efficacy and postoperative outcome of metal clamps with customized cushions and standard metal clamps during rubber dam isolation procedures.
MATERIALS AND METHODS: After institutional ethical approval and informed consent total 64 patients were randomly assigned in two groups. Group A - rubber dam metal clamp with customized cushees (n = 32), Group B - rubber dam with standard metal clamp (n = 32). After selection of appropriate clamp for Group A, Customized cushions were prepared and restoration was performed. The evaluation was done using self-designed assessment criteria which included postoperative pain, rubber dam slippage, trauma to gingival and adjacent tissues and sealing ability of both the groups. STATISTICAL ANALYSIS USED: Chi-square value was calculated with SPSS software version 18.0.
RESULTS: There was statistically significant difference between postoperative pain, rubber dam slippage, trauma to gingival tissues (P < 0.001) with reduced postoperative pain.
CONCLUSION: Cushions have played significant role in reducing postoperative pain, trauma to the gingival tissue and slippage of rubber dam clamp compared to standard metal clamps. Copyright:

INTRODUCTION

Working under isolation has been emphasized for decades and rubber dam sheet has made it possible.[1] The use of a rubber dam primarily improves vision, moisture preservation, and soft tissue retraction. It allows for the use of powerful irrigants for cleaning complex dental anatomy and also reduces the risk of foreign body ingestion or aspiration.[2]

Despite these benefits, dental dams are often neglected in endodontic and restorative procedures. According to Anabtawi et al.,[3] only 44% of respondents said they always used rubber dams during root canal treatment. The main reasons for inconsistent application of rubber dam are clamp tightness, gingival tissue damage, clamp slippage and seepage through the margins. The contact of metal clamps with gingiva and clamp slippage are two major concerns related to the usage of rubber dam which cause discomfort and pain to the patient. The resultant anxiety could lead to rejection of rubber dam usage by the patient.

With the aid of custom prosthesis, numerous adjustments are made to achieve dry-field isolation and resolve the difficulties of teeth with short clinical crowns but still success is not achieved in clinical situation.[4]

Cushee rubber dam clamp cushion (Practicon Inc., USA) is a revolutionary dental product that was created to address this issue; however, its availability is limited, and its use is limited to a collection of clamps. They are silicone stops that brace the clamp's inner side and shield the gingival tissues from the clamp's sharp edges.[5] Other techniques like jaws to be dulled before using the #8A clamp are also suggested. In addition, using the split rubber dam technique for indirect restorations also improves operating efficiency.[6] We thought of customizing a cushion for the rubber dam clamps in each patient using chairside clear silicone, on the same concept as cushees. Polyvinyl siloxane elastic material (Exaclear, GC, Europe) is a flexible material with good handling property.

A dental rubber dam clamp cushion has an elastomeric body with a tooth-engaging front face that makes contact with the tooth surface. By removing contact between the steel clamp and the gingiva or enamel, it improves patient satisfaction. Improves rubber dam seal to reduce clamp slippage and limit leakage from above or below. Protects natural tooth structure as well as delicate, expensive restorations.[4] The modifications related to rubber dam technique are still in emerging phase. In addition, there is limited literature on metal clamps with rubber dam modifications, and no clear evaluation criteria are listed in the literature. As a result, we established and validated the “Shah's And Kothari's Evaluation Criteria for Clinical Evaluation of Rubber Dam Isolation Technique.” Which included damage to gingival tissues, slippage of clamp and sealing ability along with Verbal Rating Scale (VRS) for pain evaluation.

As a result, the study aims for comparative evaluation of efficacy and postoperative outcome of metal clamps with customized cushions and standard metal clamps during rubber dam isolation procedures. Null hypothesis was there was no difference between efficacy and postoperative outcome of customized cushions and standard metal clamps during rubber dam isolation procedures.

MATERIALS AND METHODS

Ethical clearance was obtained from Institutional Ethical Committee (SVIEC/ON/DENT/SRP/19114).[7] A minimum sample size of 54 (27/group) was determined using the formula (n = Chi-square/W^2), with a 90% confidence interval and 80% power. However, the final sample size was raised to 64 (32/group) to account for a 20% dropout rate on follow-ups via telephonic communication using VRS.

After receiving signed informed consent from all patients, a total of 64 lesions in 32 patients aged 18–65 years with totally erupted premolars and molars having mild-moderate Class I caries lesions (minimum of two lesions in opposing quadrants that involved rubber dam isolation) were included in the analysis. Patients with poor oral hygiene, Class V caries, gingival disease, latex allergy, or who were medically impaired were excluded from the study. Clinical and radiographical evaluation of the selected lesions was done. Selected patients (n = 64) were allocated randomly by computer randomization (www.randomiser.org.in) into two groups. Group A: Custom cushees with rubber dam and metal clamp (n = 32), Group B: Regular rubber dam and metal clamp (n = 32). Both the restorations were performed in two separate appointments to counter any bias. Both the patients and the evaluators were blinded. The inter examiner variability of two experts in the same field with 10 years of experience was measured using the kappa test (0.80). As a result, the study was planned as a randomized double-blind clinical study. Prior to commencement of procedure patients were instructed about the pain perception by VRS to determine their pain scores.

Studervents' guidelines[8] were used to choose the clamp (Hu-Freidy, USA). Intraorally, the chosen clamp was tried in. Following clamp selection, 1.8 ml of 2% local anesthetic agent 1:200,000 lignocaine with adrenaline was injected for a conventional nerve block. Patients were advised to wait until they experienced subjective or objective signs. The effectiveness of soft tissue local anesthesia was evaluated using a probe.

GROUP A – RUBBER DAM METAL CLAMP WITH CUSTOMISED CUSHEES. After clamp selection, cushion fabrication was done. Polyvinyl siloxane impression material was injected with an auto mixing syringe over the clamp's inner jaws. A uniform flow of the material was maintained while moving from the mesial part of the jaw to the distal part, along with inferior and superior areas of the jaws for the selected clamp [Figure 1]. According to the manufacturer's advice, the material was permitted to set extra-orally for 8 min. A metal spatula and a lecron carver were used for additional manipulation or molding (GDC Fine Crafted Dental Pvt Ltd., India). Removal of the excess material was done using a BP blade (No. 11). Complete assembly of the clamp with the customized cushion was tried on the patient's tooth and the stability of the clamp was checked using the back end of an explorer. Following this, a heavy gauge rubber dam sheet (Nictone, Expert Tech Solutions, Bucharest) was selected for the isolation of the tooth and it was secured over the wings of the clamp. Now, the selected clamp and dam assembly was carefully be placed together. GROUP B – STANDARD RUBBER DAM METAL CLAMP After selection of well-fitted clamp according to the above mentioned guidelines, the selected standard stock metal clamp was placed over the patients tooth with rubber dam and clamp together technique for isolation. A heavy gauge rubber dam sheet was used for isolation. Restorative procedure was carried out.

Figure 1

Polyvinyl siloxane impression material with auto-mix syringe used to fabricate customized cushion which are depicted by arrows

On completion of the procedure, the entire assembly was removed and the cushions were discarded among the Group A. The patient's response regarding any postoperative pain was evaluated with VRS and other parameters with Shah's And Kothari's Evaluation Criteria for Clinical Evaluation of Rubber Dam Isolation Technique” [Table 1]. The content validation of Shah and Kothari evaluation criteria was carried out after evaluation by 5 subject experts who had been using rubber dam for more than 5 years in practice. All the obstacles were addressed based on which assessment criteria were built. They rated the parameter in tool into (1) essential (2) useful but not essential, and (3) not essential. The correlation coefficient of their responses was carried out which was 0.87 indicating the high validity of the criteria (Copy Right Number:-13168/2020-CO/L). A good operating light and magnification were used in the evaluation. The data was entered into Spreadsheets, and the Chi-square test was performed using IBM Corp. Released 2011, IBM SPSS Statistics for Windows, Version 18.0 (Armonk, NY: IBM Corp), (P = 0.001).

Table 1

Evaluation of postoperative pain, Shah’s and Kothari’s evaluation criteria for clinical evaluation of rubber dam isolation technique

Shah’s and Kothari’s evaluation criteria for clinical evaluation of rubber dam isolation technique
Trauma to the gingival tissues	Mild: Indentation of bow of clamps present with no bleeding and laceration.
	Moderate: Indentation of bow of clamps with bleeding present but no laceration.
	Severe: Indentation of bow of clamps with bleeding and laceration present.
Sealing ability of clamp	seepage of fluid, blood under 3.5x magnification.
Slippage of the clamp	Present or absent

RESULTS

All the 64 patients were evaluated for postoperative pain at 6 and 12 h interval with VRS, whereas a visual evaluation was performed for gingival tissue damage, clamp slippage, and clamp sealing ability under magnification by two calibrated evaluators. [Flow chart 1]

Flowchart 1

Randomized clinical trial flow chart

Postoperative pain

The statistical analysis of the results of the present study showed statistically significant difference in the performance of customized cushion and standard metal clamps in relation with postoperative pain where P value was statistically significant (P < 0.001).

At an interval of 6 h, In Group A, 20 patients had no pain while ten patients reported with very mild pain, while at 12 h all of 32 patients reported with no pain. While in Group B 10 patients reported with very mild pain, 8 patients reported with mild pain at 6 h interval. Seventeen patients had no pain while 13 patients reported with very mild pain at 12 h interval and the obtains values were again statistically significant (P < 0.001). [Table 2]

Table 2

Postoperative pain evaluation using Verbal Rating Scale at 6 h and 12 h interval

Parameters for evaluation	Group	VRS pain scoring criteria				Total	P
		No pain	Very mild pain	Mild pain	Moderate
VRS 6 h	Cushees	20	10	2	0	32	<0.001
	Standard	5	10	8	3	32
VRS 12 h	Cushees	32	0	0	0	32	<0.001
	Standard	17	13	2	0	32

VRS: Verbal Rating Scale

Trauma to gingival tissues

Out of 32 patients from Group A, 25 patients had no trauma to the gingival tissues, while 7 patients showed mild trauma when compared that to Group B 16 patients had mild trauma, 10 patients had moderate score while 3 patients had severe bleeding and laceration present and the obtain values were statistically significant (P < 0.001). [Graph 1]

Graph 1

Illustrates trauma to gingival tissues between the groups

Sealing ability of clamp

Among the sealing ability 30 patients from Group A had no seepage of fluid around the margins. When compared that to Group B out of 32 patients, 24 patients had no seepage of fluid around the margins of the clamp while 8 patients had positive sign seepage at the margins with crevicular fluid and saliva the obtain values were statistically significant (P < 0.001). [Graph 2]

Graph 2

Illustrates seepage and sealing ability of clamps between the groups

Slippage of clamp

In this parameter, all the 32 patients under Group A had no slippage of clamps compared to that of Group B which showed 6 patients had popping out of the clamp while 26 patients had no slippage or dislodgement of rubber dam clamp during entire restorative procedure. The obtained findings were not statistically significant (P < 0.010). [Graph 2]

The results of the current study's analysis revealed a statistically significant difference in the performance of customized cushion and standard metal clamps in terms of postoperative pain trauma to the gingival tissues and clamp sealing capacity. In both classes, there was no statistically significant difference in clamp slippage.

DISCUSSION

Dental dam has been in existence for over 100 years, yet this potential practice builder has been overlooked due to the misconception that its application is both time-consuming for professionals and unpopular with patients. In reality, dental dam utilization has five important benefits: (1) patient protection/risk management, (2) increased access/visibility, (3) Improved time efficiency, and (4) moisture control/improved quality: Dental dam promotes a moisture-free, uncontaminated working environment, these materials are permitted the luxury of setting under optimum conditions. (5) Infection control: Properly placed dental dam acts as an effective barrier between the oral cavity and the operative field.[910]

As very scarce literature is available on the modification of rubber dam clamps and technique, exploration in this untouched part of dentistry is need of the hour. Despite of the above-mentioned advantages the use of rubber dam is clinical practice is very less. Patient objections, time requirement, tightness of the clamp are frequent reasons for inconsistent application. Commercially available cushee are rescue for such discomfort but limited availability makes it difficult to use.[11] They are available in predetermined sizes for a particular set of clamps and customization of preformed cushees is unfeasible for all the cases. The hard metal of the jaws of the clamps can contact the patient's gums, root surface, causing pain. Sometimes, a clamp slips during dental treatment, causing the patient to jump with the resulting pain.[12] Hence, there was a need to improve the comfort of dental rubber dam clamps. The cushions made with exaclear clearly stand advantageous as the technique allows customization as per the tooth size, shape and morphology. Second, the polyvinyl siloxane materials are widely available, intuitive and convenient to use. The clamps require no alteration to allow customisation of these cushions and clamp selection is done based on regular principles. Clear silicone material is self retentive on the clamp and is robust enough to be handle the forces acting on it.

Cushions provide distinct advantages by its shielding effect due to elastic nature of material. Patient comfort is significantly increased because a steel rubber dam clamp or other hard surface does not contact gingiva or cementum. A standard clamp can utilize undercuts of teeth for its retention only when the undercuts have a definite depth, shape and location. For better retention, a clamp has to be pushed towards the gingiva beyond the greatest cervical contour of the tooth; sometimes up to the gingival margin. Since metal clamps snugly fits the margins leads tightness so to avoid this discomfort. Hence, local anesthesia was administered to the subjects before commencement of procedure. Hence VRS was preferred to measure pain at 6 and 12 h interval which was statistically significant (P < 0.01). Which is reduction in pain at 6 h interval and absolute pain at 12 h interval for customized cushion group. Such extension of a clamp to gingival margin may result in discomfort to patients causing gingival hemorrhage, injury to the gingival attachment, or cause nicking of the cementum on the root surface. Often the clamps we use are stock metal clamps and as every individual anatomy is different not every clamp will have its perfect fit.[13] The use of serrated clamps, worn out margins of the clamp, blunt edges or ill-fitting clamps frequently leads to trauma to the gingival tissue and it is an unavoidable circumstance. Also if kept for long time ischemia will cause tissue sloughing and subsequent recession.[14] Cushion reduces tissue trauma by its pliancy. Customization of stock clamps is also possible according to tooth anatomy due to good manipulative ability of material to adapt to its desired shape. The results obtained were statistically significant having less trauma as compared to conventional metal clamps with (P < 0.001).

As discussed earlier stock clamps leads to space due to poor fit leads to seepage of fluids around the margins of the tooth. Resin composite and adhesive systems are especially technique sensitive, with proper handling and adequate isolation is crucial for successful restoration and material longevity. Flexible poly vinyl silicone fills up the space between the clamp and the tooth to avoid entry of fluids reducing the seepage. Cushion act as a barrier between the tooth and the clamps brace to support the clamp and dam. The findings were statistically significant with (P < 0.001).

Slippage of the clamps is one of the reasons to avoid dam placement. The major reasons for slippage are short clinical crowns, dull inner jaws, anatomical variations and high gingival margins. Cushions give a distinct advantage of flexible transparent material with ease to manipulate, optimal consistency for an easy placement, perfect adaptation to the preparation. Cushions avoid displacement of dam and slippage and give the optimal isolation as desired.[15] Though findings were not statistically significant but were clinically significant. The disadvantages of the customized cushees are single use, nonsterilizable, difficult in application of floss tie and limited applicability where access is to be made through cervical third part of crown. Thus, the null hypothesis was rejected and more studies are needed using different clinical scenario and different elastic materials for its wide clinical application and for the validation of the evaluation criteria.

CONCLUSION

An innovative method of securing a dental rubber dam clamp includes placing the cushion and securing the clamp has proven to be fruitful and can be done chair side within no time. It also reduces the pain of the patient and enhances rubber dam seal to limit leakage and reduces clamp slippage.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.