Comparative Analysis Of Success Rate In Class II Cavities with Direct and Indirect Restorations - A Retrospective Analysis

Keywords

Class II Cavities; Direct Restorations; Indirect Restorations; Success Rate; Contour; Contacts.

Introduction

Current evidence supports the preservation of tooth structure over other invasive procedures. Restoring carious lesions and preserving tooth structure is an integral part in the field of conservative dentistry.Restoration is a term used in dentistry to describe the repair of a missing or damaged tooth structure. Restorations are classified as either direct or indirect. Direct restorations are repairs made inside of the mouth (fillings), while indirect restorations are fashioned outside of the mouth and then affixed to either the tooth or the supporting tooth structure in a separate procedure [1].

Amalgam restorative material has been widely used in dental filling material worldwide for the restoration of posterior teeth because of its easy handling procedures, well-tested material properties, and clinical success. Patients' esthetic preferences in the restoration of posterior teeth have stimulated the development of new, tooth-colored, non-metallic restorative materials. Esthetic alternatives to amalgam restorations and cast-gold inlays include direct composite resins, composite inlays, and ceramic inlays [2]. Lately, resin-based adhesives and restorative materials have stimulated an increase in the use of resin-based composites in posterior teeth [3, 4].

Direct restorations are composite and amalgam restorations. Indirect restorations are inlays and onlays [5]. The different restorative materials used for indirect restorations are ceramic, composite , metal [6, 7].

In direct composite resin restorations the most important problems were various fractures, wear, loss of marginal seal leading to pulpal irritation, post operative sensitivity, marginal staining and secondary caries [8]. Several restorative techniques have been used to minimize polymerization shrinkage and stress such as multiple increment technique, use of glass ionomer cement as sandwich technique [9]. The use of composite resin inlay/onlay technique has been widely used to reduce polymerization shrinkage. The noticeable advantages of indirect restorations relates to its better potential for generating appropriate anatomic form as well as proximal contact and contour [10, 11]. Indirect laboratory processed composite systems present aesthetic alternatives for intracoronal posterior restorations and provide aesthetic results that may also reinforce the teeth [12]. Additional benefits include exact marginal integrity, wear resistance, wear compatibility with opposing dentition, optimal esthetics, ideal proximal contacts [13].

However, for the management of caries, it is difficult to achieve the correct balance between an eagerness to remove the lesion and the continued monitoring of lesion progression [14]. The selection of either treatment strategy is relevant to the risk of creating pulp complications, because the selection of approach can mediate the quantity of caries excavation, risk of pulp injury and exposure, size of cavity preparation etc.The important factor to be considered is protecting the pulp status and remineralizing the carious structure [15, 16].

The faulty restorations invariably affects the pulp status which in turn requires endodontic therapy.Successful endodontic therapy involves many factors including proper disinfection and shaping of the root canal [17-21]. In some cases the placement of intracanal medicament also plays a major role [22]. In order to avoid that complex procedures, carious lesion to be treated at earlier stage. The aim of this present study was to analyse the success rate of direct, indirect restorations in class II cavities.

Materials and Method

Study Design

Single centered retrospective study

Ethical Approval

Approval for the project was obtained from the Institutional Review Board of Saveetha Institute of Medical and Technical Sciences, Chennai, India on Date 18/04/2020 .This retrospective clinical study evaluated the patients who received direct and indirect restorative procedures for class II cavities Saveetha Dental College, Chennai.

Inclusion Criteria

Patients aged 18-70 years who received direct, indirect restorative procedures for class II cavities, patients who received direct restorative procedures such as composite restorations, and amalgam restorations in class II cavities, patients who received indirect restorative procedures such as metal inlay and ceramic inlay for class II cavities.

Exclusion Criteria

Patients who have received restorations other than class II cavities, endodontic procedures were excluded from this study, Exclusion criteria consisted of patients who have received restorations other than class II cavities, pit and fissure sealant, temporary restorations and endodontic procedures were excluded from this study.

Data Extraction

Data extraction was done from 548 patient’s records.Data collection was accomplished using standardized electronic form designed to collect information related to subjects' demographic features, type of restoration. The final data was exported to excel and saved on a secure server for analysis. The case selection and data extraction is shown in (Flow chart 1).

Sample Size

The sampling method was used to evaluate data .Of total, 548 patients, 309 patients were selected for this study based on inclusion and exclusion criteria. Among that, 19 teeth were restored by indirect restorations and 290 teeth were restored with direct restorations.

Groups

The restorations done were divided into:
Group A-Direct restorations
Group B-Indirect Restorations

Clinical outcome

Success rate is assessed based on Patient’s visit after restoration because of pain or difficulty during mastication. All patients were followed up to note the clinical performance of restoration. If the patient’s visit was due to discomfort or minor issues, and the restoration was adjusted it affects the restoration’s success to a certain level.

Clinical Protocol

The clinical protocol for the patients undergoing restorative procedure is to assess the pulp status by pulp vitality tests, clinical and radiographic findings. After diagnostic procedures, caries excavated and decided whether direct or indirect restoration needed for the particular scenario. Most commonly preferred direct restorations are composite restorations and amalgam restorations.

Indirect restorations involve two visits, in the first visit, cavity preparation done, impression made and sent to the lab and in the subsequent visit fabrication of indirect restoration done. materials used for indirect restoration were metal, composite and ceramics.

Study Outcome

Success rate is assessed based on patients visit because of pain, improper contour and contacts after restorative procedure.And in case of direct restoration patients reported back mainly because of discomfort during mastication, and adjustments made by reducing high points and this affects the success rate to certain levels. Post operative sensitivity too affects the success rate.

Statistical Analysis

Chi- square test was done to assess these parameters. The outcome data was represented in the form of tables and graphs. The four tables represent the frequency of pulp capping procedure done based on the age, gender, teeth number and the type of restoration of the patient. The graphs represent the correlation between these parameters - Correlation of age and type of restoration, gender and type of restoration, teeth number and type of restoration.

After grouping of parameters, data was copied to SPSS software. The statistical analysis between direct, indirect restorative procedures were carried out in SPSS software. Chi square test was done to compare the direct/indirect restorative procedures to other three parameters - age, gender, teeth number and restoration type.

Results and Discussion

The clinical data base system resulted in a total of 548 patients charts, identifying direct and indirect class II restorations completed in patients over a period of one year. After applying the inclusion and exclusion criteria, around 309 teeth met with the criteria.

In this study comparing direct, indirect restorative procedures in class II MO cavities, direct restorative procedures (group A) have a higher preference, success rate than indirect restorative procedures (group B). In this study comprising 309 cases, 45 cases reported with discomfort during mastication,improper fit, dislodgement, sensitivity issues.

Among 290 direct restoration cases, 14 cases reported either due to discomfort during mastication,sensitivity issues and in these cases, proper contacts and contours were rechecked and occlusal adjustments made and 22 cases reported dislodgement of filling and in these cases, re restoration done. Among 19 indirect restorations cases,9 cases reported due to discomfort, improper fit and in these cases, 5 indirect restorations sent to lab and rechecked in occlusal aspects.

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Traditionally, indirect restorations are expected to have better longevity than direct restorations. The introduction of adhesive dentistry has changed this aspect and direct restorations have equal success rate as that of indirect restorations.

In this study, direct restorations were highly preferred in the majority of cases because of patient’s preference avoiding multi visit in case of indirect restorations. The clear indications of indirect restoration are large cavities/failed direct restorations, multiple missing cusps. Previous in vitro studies analysed the direct, indirect restorations based on the USPHS criteria such as colour match, marginal integrity, marginal discoloration, surface texture, postoperative sensitivity and gingival bleeding [23, 24]. Some clinical trials have used the USPHS criteria to evaluate the direct, and indirect composite restorations [25]. Loguerico and Dresch, 2006 stated that, 100% alpha ratings were obtained for retention criteria according to modified USPHS criteria in 12 month evaluation of direct restorations [26]. Considering the retention aspect in this study, 7 patients who received indirect restorations reported due to improper fit.

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Yip 2007, evaluated and stated that all direct posterior composite restorations were also rated excellent for surface staining criteria. Considering the direct posterior composite restorations in staining criteria in this study,it exhibited good results [27]. Turkun found that in 2 year clinical evaluation for marginal discoloration, all direct restorations showed 100% alpha ratings during six month evaluation. At two years recall evaluation, there were 5 bravos for marginal discoloration, at the end 6% of restorations had a slight crevice along the marginal interface [28, 29]. As this study is a retrospective analysis of one year,direct restorations did not exhibit any marginal discoloration in the majority of cases.

Cetin and Unlu, 2008 stated that better clinical performance might be obtained using indirect inlay systems since they are indirect composite resins specifically designed for restoring posterior teeth [30]. Manhart found that 97% alpha scores in indirect composite restorations, 93% alpha scores in direct composite restorations for post operative sensitivity [31]. Yet, the results of in vitro studies differ in clinical scenarios.

The patient’s preference for direct restorations over indirect restorations is noted in the majority of the cases. Although if it's a clear indication of indirect restoration, the clinician must emphasise the importance of giving proper contacts and contours which can be achieved by giving indirect restorations [32]. The majority of clinical decision regarding the most appropriate choice of restorative material, technique as straightforward & dictated by many factors such as lesion size, etiology, aesthetic , occlusal, endodontic, periodontal considerations-number of teeth affected, patient compliance, habit, preferences,the dentist’s own competence and underlying beliefs over the restoration [33].

As this study involves the dentists who are pursuing undergraduate courses, clinician skill plays a huge role in determining the success rate. In terms of direct restorative procedures many factors such as proper isolation, cavity preparation, placement of restorative materials should be considered when compared to indirect restorative procedures. In terms of Indirect restorative procedures, impression plays a huge role in fabricating the restoration. In this study, failure percentages in indirect restorative procedures were higher than direct restorative procedures (Table 4).

The decision making process involved when choosing to use either direct/indirect approach for any given clinical situation can be facilitated by considering the above factors. Direct composite restorations are more likely to be aesthetic, functional, durable when cavity margins are situated within enamel, free from occlusal contact, easily accessible in terms of visibility, ease of isolation and relationship to gingival tissues [34]. Apart from likelihood of significant loss of tooth substance, the main problem arising in such a situation is difficulty inherent in trying to seal subgingival cervical margins located within dentin, cementum [35].

Hashimato, 2000 stated that the majority of cavities are entirely bounded by enamel and it is thought that seal achieved at margin protects any internal resin dentin bond at floor of cavity. Lie lenberg, 2005 advocates a resin modified GIC – sandwich technique. Anderson, 2004 examined the durability for extension of carious lesion and concluded it exhibited structural durability [36]. The faulty restoration affects the pulp status requiring endodontic therapy.Many factors influencing the therapy are canal anatomy, calcified nature and in case of traumatic injuries such as avulsion, the treatment protocol differs [37, 38].

Watts, 2001 observed a large number of discoloured teeth after restorations and stated that correct diagnosis should be made and the mechanism of staining have a great outcome on treatment. In this study comprising cases restored with direct composite restoration, discoloration was not noted in the majority of the cases [39].

In virtually, every clinical case there will be more than one way to achieve the result. Many decisions regarding treatment are straightforward, as the advantages of one particular procedure outweigh its own disadvantages and the relative advantages of other available options. As long as treatment is performed with proper care, to a high standard with understanding of the concept, it will more than likely be successful.

Conclusion

Within the limitations of this study, it can be concluded that the direct restoration has a higher preference, success rate over indirect restorations in class II cavities in terms of parameters such as dislodgement of filling, discomfort and pain during mastication as it shows statistically significant difference. This disagrees with the previous evidence based on in vitro studies which stated that indirect restorations are superior to direct restorations.

Study Limitation

In this study, success rate was evaluated based on one factor in USPHS criteria. This study involved a relatively smaller number of people.

Future Scope

Long term evaluation of both direct, indirect restorations in class II cavities should be done based on modified USPHS criteria. Future studies can evaluate in a larger number of populations, the factors can be assessed based on modified USPHS criteria for more reliable clinical results.

Declaration of Patient Consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.