Dental Implants History & Practice

The first successful implant in human dentistry was performed in 1965.¹ Since that time, countless human dental patients have benefited from dental implantation, which has dramatically improved their health and quality of life.

Before the advent of implantation, teeth were saved at all costs, often to the local and systemic detriment of the patient. Now, diseased teeth are extracted and replaced with healthy implants.² It has been shown that extracting infected teeth improves the overall jaw structure by maintaining as much of the original bone as possible.

Cosmetic dentistry is a growing business in human medicine, and its popularity in the veterinary field is sure to follow. I believe that many clients would currently choose implants for their pet if they knew the choice was available.

Periodontal Health: Causes & Consequences

Limitations
Contraindications for dental implantation are determined by ethical considerations and the local and systemic health of the patient. The health status of the patient should be considered above all else. Implants require multiple surgical events beyond the initial extraction. Implantation may not be suitable in geriatric or chronically ill patients.

Implantation also has a poorer prognosis in patients with diabetes mellitus or those receiving chronic therapy with corticosteroids because of the increased risk for infection.³ Implants should not be placed near sites of current oral infection, and the oral cavity must be treated with a complete dental prophylaxis and any additional therapies as directed by the oral examination and intraoral dental radiography.³

Veterinary Dental Teleradiology

In addition, dental implants are subject to the periodontal bone loss seen with natural teeth. Reasonable assurance that the client will comply with at-home care and follow-up veterinary visits is critical.

Dental implants require an adequate amount of bone for support, which is often a concern because teeth are typically lost secondary to periodontal disease. If a patient has less than 2 mm of bone surrounding the site of implantation or if placement would encroach within 2 mm of the mandibular canal or sinus floor, implantation is not advised.

Ideally, implantation should be considered to replace lost teeth. It is an acceptable option if a patient is missing a tooth from birth but should not be considered to replace missing teeth in show or breeding patients unless a veterinarian has extracted the tooth or there is medical evidence that a tooth was previously present. A legal waiver is strongly advisable in such cases.

Implants in Practice

• Replacing a single tooth with an implant, the most common type of implantation, has the greatest long-term prognosis and cosmetic effect.
• Implants can be used without an artificial tooth (pontic) as a strengthening agent in the maxilla or mandible to avoid alveolar collapse.
• Implants can be placed as anchors or as support (pier) in a fixed bridge.
• One large implant can be used as an attachment for a multitooth span, but this is generally not recommended in veterinary patients, especially for teeth that will be subject to significant use or trauma.

Dentin Bonding: Uncomplicated Crown Fracture

Advantages of Implants
In addition to cosmetic benefits (Figure 1,right. Dental implantation offers both cosmetic and medical benefits by enhancing oral health and dentition), dental implantation offers medical benefits by enhancing proper dentition. Implantation can increase the bony strength of the jaw, primarily because of the immediate replacement of lost bone by the implant post.³ This is particularly important in the mandibles of cats and small-or toy-breed dogs.

Increased use of the tooth during mastication may help increase mandibular bone density, depending on which type of tooth is implanted. This is similar to the positive effect that exercise has on bone density in older humans.

Implantation may also help avoid orthodontic problems created by tooth loss. This is most often seen following extraction of a maxillary canine tooth, particularly in cats and small-breed dogs. The absence of a maxillary canine causes the lip to fall palatally, resulting in trauma from the ipsilateral mandibular canine (Figure 2, below. Absence of a maxillary canine causes the lip to fall palatally).

Disadvantages of Implants
There are no true medical disadvantages to implantation, other than requirement for multiple anesthetic procedures. There has been a shift toward 1-stage implantation with immediate loading in human dentistry, meaning that the tooth is extracted, the implant is placed, and impressions are taken for the crown during the same anesthetic event.⁴ A temporary crown is placed, and the permanent crown is cemented a few weeks later.

This is not recommended in veterinary patients for several reasons: First, there is generally insufficient remaining bone to facilitate implant placement into solid bone. In the vast majority of veterinary implantations, the bone must be regenerated before placement, which requires an additional anesthetic event.

Second, 1-stage implants are generally not as strong as 2-stage implants. In human patients, strict compliance is necessary to minimize trauma to the area and avoid damaging the osseointegration. This is extremely difficult in veterinary medicine, and often no neighboring teeth are available to support the implanted pontic during healing.

Multiple anesthetic events are recommended for the best prognosis in most veterinary implantation cases. The procedure can be separated into 4 steps:

1. Extraction of the damaged or diseased tooth
2. Placement of the implant and suturing after healing has occurred (after 6-8 weeks)
3. Uncovering of the implant and creating impressions following osseointegration (after 6-8 weeks)
4. Cementing of the pontic (after 2 weeks)

Because proper implantation in veterinary patients requires several additional anesthetic events, the entire process can take between 14 and 18 weeks. I have successfully implanted nonstrategic teeth with 1-stage implantation when sufficient bone was present (Figure 3, right. Single-stage implantation of nonstrategic teeth can be successful when sufficient bone structure is present), but clients should always be given a guarded prognosis if 1-stage treatment is selected. The practitioner should consider having the client sign a waiver against medical advice.

Periodontal Surgery
Oral Health = Systemic Health?

Pros and Cons at a Glance
Pros

• Cosmetic benefits
• Increases bony strength of the jaw
• Minimizes orthodontic complications associated with tooth loss

Cons

• Multiple anesthetic events
• Process takes generally 14–18 weeks

Clinical Impact
Implantation can be an effective method of restoring diseased or lost dentition in veterinary patients. It can improve cosmetic appearance and jaw strength as well as improve general quality of life. In addition, the availability of implants may convince owners to allow extraction of diseased teeth sooner in the disease process, thus improving overall patient health. The risks of implantation can be minimized by utilizing improved anesthetic drugs and monitoring.

DENTAL IMPLANTS: HISTORY & PRACTICE • Brook A. Niemiec
References

1. Intra-osseous anchorage of dental prostheses: I. Experimental studies. Branemark PI, Briene U, Adell B, et al. Scan J Plast Resocon Surg 3:81, 1969.
2. Oral Implantology. Klokkevold PR. In Saunders WB (ed): Carranza’s Clinical Periodontology—St. Louis: Saunders, 2006, pp 1071.
3. Clinical aspects and evaluation of the implant patient. Klokkevold PR, Cochran DL. In Saunders WB (ed): Carranza’s Clinical Periodontology—St. Louis: Saunders, 2006, pp 1087-1104.
4. Immediate/early loading of Neoss implants. Preliminary results from an ongoing study. Anderson P, Verrocci D, Pagliani L, Sennerby L. App Osseointegration Res 6:27-35, 2008.