INTRODUCTION

Edentulism is on its decline since the last decades, but however, it poses a substantial health problem in developing countries.^1-3 In addition, the average life expectancy is increasing worldwide, which adds up to the already existing number of edentulous people.¹ Edentulism affects individuals’ physiological, biological, social, and psychological state.⁴ It causes functional deficiency in speech, mastication, and esthetics.⁵ Conventional complete dentures are still the treatment of choice in developing countries.⁶ Several studies investigated factors that may affect patients’ satisfaction with their complete dentures, such as denture technical quality, condition of the residual ridges, and patients’ gender, age, previous denture experience, and personality.^5-8 Emotional and psychological factors also play an important role in acceptance of complete dentures.^4,5

The clinical replacement of lost natural teeth by osseointegrated implants has revolutionized treatment options in prosthodontics.⁹ The prosthetic options may be removable or fixed implant-supported/retained overdenture.

Attachment systems provide resistance to movement of the implant prosthesis and help in dissipating the functional load. Various retention mechanism like bar and clips, ball, locater, magnets, and precision attachments have been used with implant-supported prosthesis.

Even though quality standards in denture fabrication are in practice, they do not address patient-centered factors and patients’ opinion on treatment outcome. Recent studies in patient satisfaction show a shift in health care from “need-based to desire-based” options.^10-12 Various factors like gender, age, and education level affect patient satisfaction.^13,14 Patient satisfaction in prosthetic dentistry is a multidimensional concept, as is patient's perception of dental care.¹⁵

Scientific literature is sparse comparing various attachment systems and patient satisfaction in response to implant-supported overdentures. Therefore, this study was carried to evaluate the treatment outcomes through patient satisfaction for completely edentulous patients rehabilitated through implant-supported mandibular overdenture retained by two different attachment systems (ball and bar).

MATERIALS AND METHODS

A total of 30 completely edentulous patients (male or female), in the age group of 54 to 78 years (mean age 65 years), were selected. The inclusion criteria were edentulous patients in whom at least one implant could be placed bilaterally. Selection was based on clinical and radiographic examination. Routine orthopantomograms and lateral radiographs were supplemented with tomographic examinations in the mandible (Fig. 1). The patients selected were nonsmokers, free from any systemic disease, non-bruxers, with sufficient quality and quantity of bone, and prepared to comply with the follow-up and maintenance program. All patients were rehabilitated with conventional complete dentures approximately 3 months before implant placement.

Fig. 1:

Cone-beam computed tomography evaluation

Fig. 2:

Group I ball attachment system

Fig. 3:

Group II bar attachment system

The implant system used in this study was EZ Hi-Tec implants (Life Care India). A total of 60 implants (in 30 patients) were placed in the interforaminal area of mental symphysis (two implants per patient). Attachment system was chosen based on randomization. A total of 15 persons had a ball attachment system (Group I) (Fig. 2), and the remaining 15 persons had bar attachment system (Group II) (Fig. 3).

Prosthodontic Protocols for Group II – Bar-clip Attachment

The surgical placement of dental implants was similar to the procedure already described for the ball attachment. Impression was made with closed tray technique (Fig. 5). Healing abutments were placed over the implants and full-thickness flap was closed with 5-0 silk sutures. On the model, castable nonhexagonal University of California, Los Angles sleeves were attached to the lab analog. Prefabricated bar pattern sleeves were used for connecting adjacent implants with pattern resin. The pattern was invested in phosphate-bonded investment and casting carried out with conventional casting procedures. It was finished and polished. The maxillary complete denture was duplicated and working cast fabricated with type IV dental stone. Face bow recording was made and subsequently transferred to Hanau Wide-Vue articulator. The intaglio surface of the mandibular denture was relieved to accommodate the bar attachment. Bar attachment was placed on the cast and brass clips with plastic sleeves were placed in position. Autopolymerizing resin was used for incorporation of bar-clip attachment using window technique. The healing abutments were removed and bar attachment placed in situ using hex driver. Orthopantomogram was done to evaluate the accurate fit of bar attachment and implant. Occlusal adjustments were done (Fig. 6).

Fig. 4:

Pick up of ball attachment and intaglio surface of denture

Fig. 5:

Closed tray technique for bar attachment

Fig. 6:

Bar in situ and intaglio surface of denture

Evaluation of Patient Satisfaction

General satisfaction, ability to masticate, and esthetic outcome of the prostheses were recorded and quantified with a verbal rating scale at 1 week, 1, 3, 6, and 9 months following insertion of implant-supported prosthesis.

RESULTS

This study was taken up to evaluate the treatment outcomes of completely edentulous patients rehabilitated with immediately loaded implant-supported mandibular overdenture retained by two different attachment systems.

DISCUSSION

Implant-supported prosthesis to a large extent has reduced the problems associated with conventional complete dentures and has greatly improved retention, stability, patient satisfaction, and masticatory capacity.

Various attachment systems have been used in implant-supported overdentures like bar and clips, ball, locater, magnets, and precision attachments to augment retention and stability. Numerous studies regarding the immediate loading of splinted implants retaining/supporting mandibular dentures have reported promising results, but studies comparing splinted and unsplinted attachments for supporting overdentures with immediate loading are limited.

Other studies evaluated treatment outcome of immediately loaded implants on clinical parameters like peri-implant tissue health and marginal bone loss; however, only a few studies have carried out comprehensive evaluation of treatment outcomes including patient satisfaction and masticatory capacity. Therefore, this study was carried out to evaluate treatment outcomes of completely edentulous patients rehabilitated with immediately loaded implant-supported mandibular overdenture retained by two different attachment systems (ball vs bar).

The implant system selected for this study was a root form implant (EZ Hi-Tec, Life Care India) that has 1 mm implant collar with micro- and macrogroves with roughened surface for osteoconductive action that increases initial stability and shortens healing period, which is suitable for immediate loading. Randomization was carried out to divide the patients in two groups, group I (ball attachment) and group II (bar attachment). Random sampling method was employed so that there was no preferential treatment in selection, which might introduce selectivity bias. Various researchers have recommended either two or four implants in the interforamina region in the mandible to retain or support an overdenture.^16-18 Although increase in number of implants enhances retention and support, it also increases cost and hygiene measures and complicates designs. Clinical studies have proved that the number of implants used to retain an overdenture does not influence the treatment outcomes.¹⁹ Systematic reviews and randomized clinical trials have also concluded that two implant-supported overdenture should be the minimum gold standard treatment for edentulous patients.^20,21 Hence, in this study, two EZ Hi-Tec implants were placed in the interforamina region of the mandible to support an overdenture.

Various attachment systems are available, and there is adequate scientific data to support their routine use in clinical practice for implant-retained/supported overdentures. These include ball (Dalla Bona locator systems), bar (round bar, Hader bar, Dolder bar), and magnetic attachments. We preferred ball and bar attachments since these are commonly employed in routine clinical practice for retention of overdentures, and there are enough scientific data to support their routine use.^20,21

Sufficient scientific literature supports the claim that implant-supported overdenture effectively rehabilitates completely edentulous patients with improved retention, stability, patient satisfaction, and masticatory capacity, but conventional complete denture is still widely used for the same. Immediate loading protocol is equally effective as early and delayed loading protocols. Overdenture supported by two implants should be the minimum gold standard in the rehabilitation of completely edentulous patients. The selection of a specific attachment system whether ball or bar attachment does not affect the overall success or patient satisfaction.^22,23 It is important to follow the manufacturer's recommendations and adhere to the standard surgical and prosthodontic protocols for better results.

CONCLUSION

Immediate loading of implants proved to be a successful treatment modality for rehabilitation of completely edentulous patients with minimum of two implants placed in the interforamina region to support an overdenture. Both the attachments studied, i.e., ball and bar attachments, provided adequate retention for mandibular complete dentures with minimal postoperative complications, and patient general satisfaction improved with implant-supported overdentures for both ball and bar attachments (Tables 1 to 4). Implant-supported overdentures over two interforaminal implants should be considered as a minimum gold standard in the management of complete edentulism.