Peri-Implantitis; Is there Something that we are Overlooking?

This article highly relevant for dentists who base their choice of implant on clinical evidence.

 The idea of replacing ones missing teeth with titanium implant roots and ceramic crowns has gained widespread popularity over the previous few years. According to the latest Adult Dental Health Survey, about half a million people have at least one dental implant in their mouth. However, as the number of implants being placed each day rises, dentists are now also observing an increase in cases of peri-implantitis; an inflammatory condition characterized by the destruction of oral soft and hard tissues that surround a dental implant. It was not even until a decade ago, when dentists believed this condition to be non-existent. But now, this condition is on a rise and about 56% implants have been shown to pre-maturely fail as a result of peri-implantitis[1]. Hence, there is a need to identify the reasons behind this condition, so that pre-mature implant failures can be minimized.

Dentists, researchers and material scientists have come across various factors that can cause peri-implantitis. Some of these factors have been summarized in Table 1.

Table 1. Factors Influencing Development of Peri-implantitis ¹

This study has reviewed various causes of development of peri-implantitis after implant placement, and has questioned the claims that put responsibility of implant failure due to peri-implantitis, solely on the patients. Rather, previous studies as well as findings of the current study suggest that the main reason of implant failure following peri-implantitis to be due to poor implant design selection. 

In the current study, an online poll of 500 dentists was conducted, in addition to visiting 900 dental clinics in the EU and randomly asking 70 dentists who were attending the IDS Dental Show (Germany, 2015) about their professional opinion regarding the main cause behind peri-implantitis.

Interestingly, the results of this study indicated that most of the dentists were not familiar with the main reason behind the development of peri-implantitis (Fig. 1a)

Is there Really a Link between Surgical Precision and Development of Peri-implantitis?

Any kind of peri-implant pathology has been classically associated with the plaque-induced inflammatory changes in the oral tissues surrounding the dental implants. These inflammatory changes result in the destruction of the peri-implant osseous tissues, which ultimately results in the loosening and finally the loss of an implant[2].

The Relation Between Gap Formation and Prevalence of Peri-implantitis

The accumulation of disease causing bacteria at the implant-abutment interface has been shown to be an essential factor that can cause peri-implant inflammation. This problem can be averted by ensuring an optimal fit between the implant framework and infrastructure. Implant fit can either be of a passive type which results due to careful and precise insertion of the framework over the implant, or it can be an active fit that is usually caused by an external force, such as in-screw retained frameworks.

Implant Design, Torque and Peri-implantitis

Application of force during implant insertion has also been shown to affect the incidence of per-implantitis. A study conducted by Steinbrenner et al[3]. calculated the difference between the manufacture calibrated and the actual torque values of various types of wrenches that were used to tighten dental implants. The results of this study indicated that the operator experience as well as the design of the wrench played a pivotal role in determining the torque value in implants. Too much force lead to excessive tightening of the implant framework, thereby generating more strain over the implant system. Similarly, too loose an implant would create gaps between the implant-framework joint. Both these conditions would expose the implant system to falling a prey to peri-implantitis.

The Final Word

From the above discussion, it can be concluded that in order to reduce strain and gap formation in implants systems, optimal fit of the implant-abutment interface must be ensured. However, in clinical practice it has been observed that despite surgical expertise and the use of an appropriate surgical protocol, a certain level of gap formation can still not be avoided[4]^,[5],[6]. Studies have shown bacterial penetration into implant systems when gaps were reported to be up to 49μm[7]. However, contemporary research has revealed an optimal biological response and fit of implants when the gap was smaller than 1μm.

[1] Smeets, Ralf, et al. “Definition, etiology, prevention and treatment of peri-implantitis–a review.” Head & face medicine 10.1 (2014): 1.

[2] Esposito M, Grusovin MG, Worthington HV. Interventions for replacing missing teeth: treatment of peri-implantitis. Cochrane Database Syst Rev 2012; 1: CD004970.

[3] Steinebrunner L, Harder S, Wolfart S, Freitag-Wolf S, Kern M, The Precision of Mechanical Torque Wrenches Used for Implants in Dental Offices. The International Journal of Prosthodontics [2015, 28(5):527-530]

[4] Rimondini, L., Marin, C., Brunella, F.,Fini, M., Internal contamination of a 2-component implant system after occlusal loading and provisionally luted reconstruction with or without a washer device. J Periodontol 2001; 72(12): 1652-7.

[5] Steinebrunner, L., Wolfart, S., Bossmann, K.,Kern, M., In vitro evaluation of bacterial leakage along the implant-abutment interface of different implant systems. Int J Oral Maxillofac Implants 2005; 20(6): 875-81.

[6]  Piattelli, A., Scarano, A., Paolantonio, M., Assenza, B., Leghissa, G.C., Di Bonaventura, G., Catamo, G.,Piccolomini, R., Fluids and microbial penetration in the internal part of cement-retained versus screw-retained implant-abutment connections. J Periodontol 2001; 72(9): 1146-50

[7]  Binon, P., Weir, D., Watanabe, L.,Walker, L., Implant component compatibility. Tissue integration in oral orthopedic & maxillofacial reconstruction, ed. Laney, W.,Tolman, D.1992, Chicago: Quintessence Publishing. 218–226.