Should Craniofacial Growth Be a Consideration in Dental Implant Treatment?

Clinical Professor of Periodontics, Baltimore College of Dental Surgery, University of Maryland Dental School, Baltimore, Maryland; Private Practice, Yardley, Pennsylvania

As highlighted in a case report beginning on p. 482 of this issue, growth and development in an adolescent female patient seems to have affected the anterior teeth splinted by a bonded fixed partial denture (FPD). The outcome is that years later, the teeth appear intruded relative to their adjacent units. This rather ironic result is important information to share. Much has been heralded about the interaction and adverse impact of growth and development on the function and esthetics of dental implants placed in young adolescents. However, the aforementioned article also refers to the effect of craniofacial changes in a patient who was in his late 50s when dental implants were placed.

It was more recently recognized that because craniofacial growth is a physiologic process, it could impact adults treated with dental implants.¹ For many clinicians, dental implants have been a bedrock element in treatment planning. Thus, the question of how this information should influence the way clinicians plan and treat their patients going forward is an important one. Should we modify our care? Should we abandon such care?

To address this issue, I sought the input of three clinicians from two practices in Beverly Hills, California. One of the practices is limited to periodontics and surgical implant placement (Dr. Oded Bahat), while the other is limited to prosthodontics (Drs. Fereidoun Daftary and Ramin Mahallati). These clinicians, who have published and presented extensively on this topic, provide answers to several questions that reveal emerging thoughts on the subject.

Dr. Paul S. Rosen: When did you first become aware of how growth and development was affecting your adult patients with dental implants that were placed, and what were the original observations?

Dr. Oded Bahat: I first became aware of it approximately 7 to 8 years ago. The initial signs I observed were vertical variations of the soft tissue and the incisal edges of the crowns relative to adjacent teeth. Some of the common occurrences were thinning of the soft tissue and open contacts between implants and adjacent teeth.

Dr. Ramin Mahallati: In 2001 Dr. Daftary showed me a case in which the implant-supported crown was slightly apical and quite facial compared to the adjacent teeth. In clinical photographs, all the teeth except for the implant crown seemed to be in the exact same position between the initial placement of the restoration and the photographs a few years later. At the time we thought the implant had somehow moved. Originally, we started looking into the cause of the implant movement. Over the years with closer observation, we began to notice similar discrepancies in more patients who were treated with dental implants. We also started noticing open contacts that were unexplainable.

Rosen: In regard to how this knowledge has affected the way you now practice, how does this issue impact specifically your restorative plan?

Mahallati and Dr. Fereidoun Daftary: We are more intimately involved with the surgical planning of the case, not only in terms of which position to place the implant but also the size and trajectory of the implant and the micropositioning within the alveolus. For prosthodontists, risk assessment is always an integral part of treatment planning. There are times, particularly in a high-risk patient, when implants might not be the best choice for tooth replacement. Ample discussion must take place with the patient as to the possibility of such a craniofacial change, the unknown nature of the movement, and the possible need for correction at a later time. For prosthetic corrections and modifications, retrievable restorations make correction easier. To this end, we have tried some adhesively retained minimal restorations for cemented cases.

Rosen: How does this issue affect your surgical plan?

Bahat: The changes are in the preplanning stage and the surgical phase. In the preplanning stage, patients with high esthetic needs, a high smile line, or a long or short face present with higher risk; therefore, a clear and informed consent as to risks and benefits is discussed with the patient. The final treatment suggestion reflects an algorithm of risks versus benefits.

In the surgical stage, implant selection, including its macrostructure and microstructure and diameter, is of great importance in areas where anticipated changes may create an esthetic disharmony. The placement of the implant and the osteotomy vectors should be such that future changes can be accommodated.

Rosen: In light of this understanding, are there certain patients or areas where you will no longer treatment plan for dental implants?

Bahat: No. Placement will depend on added risks for a given patient and not specifically on location. For example, open contact, which occurs in approximately 65% of patients treated, can be resolved by a new crown. Vertical discrepancy in the anterior maxilla creates a different challenge in patients with a high versus low smile line. In summary, the patient, not the location, is the variant.

Mahallati and Daftary: There are patients for whom we will not recommend dental implants. Risk assessment and the cost-benefit ratio are the most important aspects in deciding if the patient is a poor candidate for dental implant therapy. For example, a young female patient with an elongated face and high smile line with a congenitally missing lateral is very high risk and, perhaps, better served with a resin-bonded FPD with a single retainer. On the other hand, open contact between a posterior tooth and implant crown, although more common, can be easily remedied and presents a lower risk for treatment.

Rosen: Doctors Mahallati and Daftary, have you seen this growth and development issue impact segmental FPDs in adolescents or adults?

Mahallati and Daftary: Yes. The most dramatic discrepancy, however, is with the single-tooth restoration. The change is a relative change between the moving segment (teeth) and the stationary segment (implant). The larger the segment, the less obvious the discrepancy will be. This is not true in a case of unilateral reconstruction by dental implants, where, for example, the right side is implant supported and the left side is not.

Rosen: How do you think this should impact the future design of dental implants?

Bahat: In my opinion, implants in the future will need to have several features. First, they’ll have to be easy to retrieve without causing large residual defects. Second, implant design will need to allow for a normal physiologically reduced facial-lingual bone and soft-tissue dimension. And, third, implant design will need to provide for increased volume of bone and soft tissue during initial placement.

Rosen: In summary, this candid discussion points to the necessity of preserving the natural dentition where possible. However, in those situations in which this may not be possible, I am more concerned about the ability to provide solutions that are modifiable. In my treatment planning for young patients, the question of whether to avoid implants in the esthetic zone is something that I weigh heavily. For older patients, I believe it is critical to rely on screw retention in all situations. Like everything else, the anvil of time will hammer out our solutions based on the emerging information gained through observation and experience.

Reference

1. Daftary F, Mahallati R, Bahat O, Sullivan RM. Lifelong craniofacial growth and the implications for osseointegrated implants. Int J Oral Maxillofac Implants. 2013;28(1):163-169.

Doctors interviewed

Oded Bahat, BDS, MSD
Private Practice
Beverly Hills, California

Fereidoun Daftary, DDS
Private Practice
Beverly Hills, California

Ramin Mahallati, DDS
Private Practice
Beverly Hills, California