Top five reasons for long-term implant success
By: Michael S. Block, DMD; Academy News Guest Contributor
Editor’s Note: This article provides clinicians with five main factors that relate to long term success. Long term represents the lifespan of the patient, often requiring over 40 years of function on the implant restoration.
Long term follow up of implants must consider decades of functional stability
Implant placement and restorative care should consider a long term solution which may extend to the lifetime of their patient. For example, a 25 year old patient will have a projected lifespan into her 90’s. For the patient in their 40’s requiring replacement of failed teeth their expected lifespan will require over 40 years of function on their implants. Depending on the age of the patient, considering the patient’s lifespan, some implants may require over 70 years of function and stability. Over time, the restoration should be able to be retrieved and modified as necessary. The treatment strategy should withstand the natural trauma from years of chewing foods with varying textures. Over engineering the implant and prosthesis design is advantageous for long term implant success.
The final restoration must be hygienic.
Patients need to be able to clean their implant restorations effectively at home as they age because routine maintenance decreases over time. Marginal bone loss on full arch maxillary restorations after 5 years is seen in 50% of implants. When the prostheses had a minimal flange, peri-implantitis was found in 12%. Difficulty with hygiene maintenance is reported by 64.5% of patients with maxillary full arch hybrid style prostheses. Plaque coverage on the intaglio surface exceeded 50% with biofilm present in over 60% of the prostheses surfaces.
What are the solutions? For some reason, clinicians do not treatment plan full arch implant borne prostheses the same way they treatment plan a single implant supported tooth. When a single implant restoration is planned the clinician recreates the alveolus for optimal implant positioning and a natural emergence of the crown. This allows for proper embrasures to be developed and follows all of the principles dentists learn to allow for functional restorations which can be maintained by the patient throughout their life.
Grafts need to last over time.
The implants should be placed into grafts that have low resorption profiles that will be present for the lifespan of the patient. Onlay grafting with materials such as allografts and autografts with significant “remodeling” may result in less bone present due to the nature of bone remodeling. Xenografts that are processed at high temperatures are less prone to resorption over time.
Thin bone resorbs over time
The facial bone thickness may be an important prognosticator for future bone thickness around an implant. When the facial bone thickness is 1 mm or less, progressive bone resorption can occur with accompanying vertical bone changes. In contrast, sites with thicker bone have less progressive bone thickness loss.
Because of the nature of the thin bundle bone on the facial of maxillary teeth, after tooth removal remodeling occurs with loss of the bundle bone. This is inevitable. Grunder and Buser recognized that labial bone thickness may decrease over time hence the need to start with 2 mm bone thickness, anticipating thinning of the facial bone.
Patients have systemic disease and they do age which need to be considered when choosing an implant solution
Variables associated with an increased hazard of failure include: osteoporosis, alcohol use, soft grafts, debilitation/frailty and short implants. Risk factors for early implant failure are osteoporosis, alcohol use, and PCN allergy, smoking status, and depression. Patients who take Serotonin reuptake inhibitors (SSRI) have an increased risk for implant failure.
Appropriate risk discussion with the patient is recommended. Malposed implants or implants placed into soft bone grafts are associated with implant failure. Patients develop debilitating health issues as they age and even though their implants were placed when their health was good, after they age and become frail, they can develop progressive bone loss on implants necessitating implant removal. As our patients age we must continue to monitor them and adjust restorations and hygiene visits as needed as their general health decreases.
Keep these five points in mind to have long term implant success.
Dr. Block is clinical professor, Department of Oral & Maxillofacial Surgery at LSU School of Dentistry; and in private practice in Metairie, La.
Disclosure: Dr. Block has a financial association with X-Nav (stocks) and Jet Investments (stocks).
