Economic Evaluation of Single-Tooth Replacement Using Fixed Dental Prosthesis or Implant-Supported Single Crowns

Private Practitioner, Under Supervision of Faculty of Medicine, University of Bern, Switzerland

^*Corresponding author: Varga Thomas Gabor Johan, Private Practitioner, Under Supervision of Faculty of Medicine, University of Bern, Switzerland

Copyright^© 2020 genesis pub by Gobar Johan VT, et al. CC BY-NC-ND 4.0 DEED. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives 4.0 International License., This allows others distribute, remix, tweak, and build upon the work, even commercially, as long as they credit the authors for the original creation.

DOI: https://doi.org/10.52793/JOMDR.2020.1(1)-01
 

Table 1: Positions of single-tooth restorations according to the Fédération Dentaire International (FDI) Group A, ISC.

The choice of treatment was based on the preferences of the patients and the dentist, but was also based on common indications for FDPs, such as bone availability or caries on adjacent teeth. All patients had received comprehensive treatment for their periodontal, endodontic, cariologic, esthetic and functional needs. The pretreatments performed in the two groups included apicoectomy, tooth extraction, root canal treatment, crown build-ups with or without core and post, removal of defective reconstructions, fabrication of temporaries, and ridge augmentation using a bovine-derived bone graft (Bio-Oss, Geistlich Biomaterials, Wolhusen, Switzerland) as well as a resorbable membrane (Bio-Gide, Geistlich Biomaterials, Wolhusen, Switzerland). The pretreatment therapies performed in the two groups are listed in (Table 2).
 

For fixed dental prosthesis abutment teeth were prepared using different diamonds and a red counter angle hand piece with ample cooling. The abutment teeth of group B were covered and protected using temporary crowns, which were cemented using Tempbond (Kerr-Hawe SA, Bioggio, Switzerland). Porcelain fused to metal fixed dental prosthesis was fabricated in all cases. All patients were asked to immediately report any complications or complaints. The patients were recalled in approximately six-month intervals, with a dental hygienist performing periodontal reevaluation and periodontal recall. Implant surgery consisted of a crestal incision extending to the sulci of the adjacent teeth. Buccal and lingual full thickness flaps were raised to allow inspection of the available bone dimension and volume. The diameter and the length were chosen based on the anatomical and radiographic situation and placed according to the manufacturer’s recommendations.

The implants were placed in either a transmucosal or a semi-submerged position followed by torqueing of the healing caps and suturing. Patients were requested to rinse twice daily with 0.02% Chlorhexidine solution for two weeks. After an average of 4.5 months of healing, impressions were taken at the implant level. The technician was instructed to choose the most suitable abutment and to produce a single crown made of porcelain fused to metal. All of these crowns were fabricated in the same dental laboratory by the same technician and were cemented using resin-reinforced glasionomer cement GC Fuji PLUS (GC Austria GmbH, Flums, Switzerland).

Patient Records

The following parameters were recorded based on the patients’ charts and appointment schedules:

1. Number of visits and time (in hours) needed for pretreatment of edentulous space and/or the teeth adjacent to the edentulous space
2. Number of visits and time (in hours) needed for the actual reconstruction, tooth preparation, implant placement, impression taking, try-ins of FDPs or single crowns
3. Number of visits and time (in hours) needed for management of either biological or technical failures as well as complications during the maintenance phase

Costs

Only direct costs were taken into consideration in the present analysis. Indirect costs, such as staff salaries, overhead costs, patient travel costs, and lost earnings, were not included. For the direct treatment costs, to ensure proper estimation, both dental clinical and laboratory costs were considered. For the FDP options, anesthesia for abutment tooth preparation as well as temporary restorations was included in the dental clinical costs. The costs of the two different treatment modalities were calculated based on the national fee scheme in Switzerland, provided by the Swiss Dental Association, using a point scheme used by health insurances for reimbursement purposes, which has not changed since 1994.The costs of the dentist’s treatment time, any biomaterials applied, implant components used, as well as the fee for the laboratory technician (based on the reimbursement fee used by Swiss health insurances for technicians’ fees) were separately listed for the pretreatment phase, for the actual reconstructive phase, as well as for the maintenance phase. Dental hygiene fees were not included.

Statistics

Descriptive statistics were computed using medians and standard deviations for all variables. Comparisons of two means were performed with Wilcoxon-Mann-Whitney tests due to the small sample size. No correction for multiple testing was applied due to the explorative nature of this study. The level of significance was set at 0.05. All calculations were done with R, version 3.2.2 (The R Project for Statistical Computing, Vienna, Austria) using the additional package “exact Rank Tests”.

Results

Sample

The sample consisted of n=59 single-tooth replacements in 53 patients which were performed between May 1995 and November 2005 by the same private dentist. Among the single-tooth replacements, n1=30 were treated with an implant-supported single crown (ISC) and n2=29 with a fixed dental prosthesis (FDP).

Figure 1: Example of a fixed dental prosthesis for replacing tooth number 36.

Figure 2: Example of an implant-supported single crown for replacing tooth number 41.

Out of the 53 patients, 33 were female and 20 male. In group A, ISC, the mean age was 51.69 years (range: 23.10-80.10); in group B, FDP, the mean age was 52.61 (range: 19.80-75.20). The factors determining the treatment decision are summarized in (Table 3).

The reasons for choosing FDP treatment instead of ISC treatment were indicated in Table 4.

Follow-up Time

The average follow-up time was 27.60 months (±17.15) in the ISC group and 85.18 months (±34.17) in the FDP group. The follow-up time was significantly shorter for ISC than for FDP (p<0.0001).

Number and Duration of Visit

In (Table 5), the numbers of visits needed for the preparation of the site, for the actual replacement of the missing tooth and for taking care of biological and technical complications during the maintenance phases as well as the total number of visits were listed. While fewer visits were needed in the implant group during the pre-treatment phase, more appointments were scheduled during the surgical phase and the implant healing period. The total number of visits was statistically insignificantly higher in the ISC group (Figure 3).

Figure 3: Mean values and standard deviations of the number of visits needed during the pre-treatment and treatment phase ISC and FDP as well as for taking care of complications.

When the actual chair side time was calculated, it became obvious that the pre-treatment was more time consuming for FDPs, whereas due to surgery, the treatment duration for ISC was statistically significantly higher (Table 5, Figure 4). No statistically significant differences in total chair side times were found when the two groups were compared.

Figure 4: Mean values and standard deviations of the treatment time in hours needed during the pre-treatment and treatment phase of ISC and FDP as well as for taking care of complications.

Economic Differences between FDP and ISC Treatment

Pre-treatment fees and the costs for the dental technical work were statistically significantly higher in the FDP group (Table 6). Except for the costs of complications, which were low, ISC showed predominantly lower values than FDP. The last variable marked with a (^*) symbol presents the total fees if a flat rate of CHF 50 for each visit would be added in consideration of opportunity costs [1].

Figure 5: Mean values and standard deviations of the treatment costs needed during the pre-treatment and treatment phases of ISC and FDP as well as for the dental technician.

Complications

A list of complication that occurred in the two treatment groups was presented in Table 7.

Discussion

The aim of this study was to evaluate and compare the cost-effectiveness of two different treatment alternatives (ISC and FDP) for replacement of a single missing tooth in a private dental practice environment. This question is important for the involved members of the dental health care system (patients, dental suppliers, insurers and dentists), who may have differing perspectives and expectations.

Economic outcomes are commonly evaluated by cost-effectiveness ratio analyses, which estimate the relative efficiency of the alternatives by holding the outcome constant. This approach is frequently applied in health care to assess the cost-efficacy of competing therapies for similar health conditions, such as different treatment modalities for missing teeth [4]. As long as the outcome is the same for all alternative therapies, the approach is essentially a cost comparison, with the lowest cost alternative being preferred. The therapy that requires fewer resources, as measured by clinician time and training, andcost of materials, is more efficient [12,13,4]. A further study with the purpose of reviewing available literature on the health economic implications and cost-effectiveness of dental implants came to the conclusion that for single- tooth replacement, single-implant treatment was a cost-effective treatment option in comparison with a traditional three-unit fixed dental prosthesis [7].

In the present investigation, ISC treatment required on average one additional visit compared to FDP treatment, but the actual chairside time of ±5 hours was equal in the groups. Pretreatment costs and costs for dental technicians were significantly lower in the ISC group. Except for complication costs, which were very low compared to the other costs, ISC showed lower values than FDP for treatment and material costs and also for total costs, the differences were statistically not significant. However, we only assessed initial costs, not lifetime costs, and for all comparisons made within this study, a sound periodontium was confirmed prior to treatment, based upon general clinical examination together with X-ray diagnostics. Satisfaction of the patients with their dental treatment was not documented.

The results of the present study indicate that 33.3% of ISC patients and 31.0% of FDP patients experienced some kind of complication during treatment. In a similar study, the lowest percentage of complications occurred in single-crown therapy (25%), and the highest (35%) in 3-4unit FDP groups [14]. In a recent study on zirconia-basedrestorations, the 5-year Kaplan-Meier survival probability was 98.3% for implant-supported crowns and 97.3% for tooth-supported crowns [15]. Therefore, implant- supported crowns seemed to be equally or less frequently affected by complications, but further studies are needed to assess exact values on long-term stability of both treatment modalities.

Apart from functionality and cost-efficiency, an important aspect is soft tissue esthetics, especially in the front tooth region. Using implant-supported crowns for single-tooth replacement in the anterior maxilla, it was possible to obtain esthetic peri-implant soft tissue results with ideal ridge forms with a minimum width of 5.5 mm [16]. The relevant literature on the optimal therapy for the replacement of a single missing tooth clearly favors implant-supported single crowns [1,3,4,6,7,11,17-19]. ISC treatments resulted in superior long-term survival compared to FDPs, led to better improvements in oral health- related quality of life, and were found to be a more cost-effective treatment modality than FDP.

he present investigation focused on the cost-effectiveness of two common treatment modalities for single missing tooth replacement. The data were collected from a dental practice in Switzerland, and as the values were similar to those from another study on this topic [1], the results can likely be seen as representative for the Swiss dental health care system. The precise acquisition of prices and treatment hours and the long follow-up times can be regarded as additional strengths of our study. The sample size of 59 cases could be seen as a limitation of this study, especially as the total costs were clearly in favor of the ISC treatment, but statistically there was no significant difference between the two groups. However, in agreement with previous studies, our results provided further evidence of a better cost-effectiveness ratio for ISC compared to FDP treatment [20].

In conclusion, the emerging consensus from the present study and from the available literature is that for single-tooth replacement, crowns on dental implant represents a cost-saving, longer-lasting and quality-of-life-improving treatment option in comparison to a tooth- supported 3-unit fixed dental prosthesis. In particular in clinical situations which involves teeth with minor or no restorations and/ or favorable bone conditions for standard placement, reconstruction with implants is to be recommended.

References

1. Bragger U, Krenander P, Lang NP. (2005) Economic aspects of single-tooth replacement. Clin Oral Implants Res. 16(3):335-41.
2. Jivraj S, Reshad M, Chee WW. (2008) Transitioning patients from teeth to implants utilizing fixed restorations. J Calif Dent Assoc. 36(8):599-606.
3. Antonarakis GS, Prevezanos P, Gavric J, Christou P. (2014) Agenesis of maxillary lateral incisor and tooth replacement: cost-effectiveness of different treatment alternatives. Int J Prosthodont. 27(3):257-63.
4. Torabinejad M, Anderson P, Bader J, Brown LJ, Chen LH, et al. (2007) Outcomes of root canal treatment and restoration, implant-supported single crowns, fixed dental prosthesis, and extraction without replacement: a systematic review. J Prosthet Dent. 98(4):285-311.
5. Nickenig HJ, Spiekermann H, Wichmann M, Andreas SK, Eitner S. (2008) Survival and complication rates of combined tooth-implant-supported fixed and removable partial dentures. Int J Prosthodont. 21(2):131-7.
6. Kim Y, Park JY, Park SY, Oh SH, Jung Y. (2014). Economic evaluation of single-tooth replacement: dental implant versus fixed dental prosthesis. Int J Oral Maxillofac Implants. 29(3):600-7.
7. Vogel R, Smith PJ, Valentine W. (2013) Evaluating the health economic implications and cost-effectiveness of dental implants: a literature review. Int J Oral Maxillofac Implants. 28(2):343-56.
8. Al-Shammari KF, Al-Ansari JM, Al-Khabbaz AK, Nociti Jr FH, Wang HL. (2005) Factors associated with implant recommendation for single-tooth replacement. Implant Dent. 14(2):201-8.
9. Christensen GJ. (2008) Three-unit fixed prosthesesss versus implant-supported single crowns. J Am Dent Assoc. 139(2):191-194.
10. Al-Quran FA, Al-Ghalayini RF, Al-Zu'bi BN.(2011) Single-tooth replacement: factors affecting different prosthetic treatment modalities. BMC Oral Health. 11(1):34.
11. Beikler T, Flemmig TF. (2015) EAO consensus conference: economic evaluation of implant-supported prosthesis. Clin Oral Implants Res. 26:57-63.
12. Salinas TJ, Eckert SE. (2007) In patients requiring single-tooth replacement, what are the outcomes of implant- as compared to tooth-supported restorations? Int J Oral Maxillofac Implants. 22(7).
13. Scheuber S, Hicklin S, Bragger U. (2012)Implants versus short-span fixed bridges: survival, complications, patients' benefits. A systematic review on economic aspects. Clin Oral Implants Res. 23:50-62.
14. De Boever AL, Keersmaekers K, Vanmaele G, Kerschbaum T, Theuniers G. (2006) Prosthetic complications in fixed endosseous implant-borne reconstructions after an observations period of at least 40 months. J Oral Rehabil. 33(11):833-9.
15. Nejatidanesh F, Moradpoor H, Savabi O. (2015) Clinical outcomes of zirconia-based implant- and tooth-supported single crowns. Clin Oral Investig. 20(1):169-78.
16. McGuire MK, Scheyer T, Ho DK, Stanford CM, Feine JS. (2015) Esthetic outcomes in relation to implant-abutment interface design following a standardized treatment protocol in a multicenter randomized controlled trial--a cohort of 12 cases at 1-year follow-up. Int J Periodont Rest Dent. 35(2):149-59.
17. Bateman G, Barclay CW, Saunders WP. (2010) Dental dilemmas: Endodontics or dental implants? Dent Update. 37(9):579-94.
18. Fugazzotto PA. (2009) Evidence-based decision making: replacement of the single missing tooth. Dent Clin North Am. 53(1):97-129.
19. Kim SG, Solomon C. (2011) Cost-effectiveness of endodontic molar retreatment compared with fixed dental prosthesis and single-tooth implant alternatives. J Endod. 37(3):321-5.
20. Zitzmann NU, Krastl G, Weiger R, Kühl S, Sendi P. (2013) Cost-effectiveness of anterior implants versus fixed dental prosthesis. J Dent Res 92(12_suppl):183-8.