| Unlike natural
teeth, the dental implant and its abutment are composed of titanium and cannot
attach to gingival fibers. Gingivodental fibers and transseptal fibers do not
exist in the gingival tissue surrounding the implant abutment (Figure 1).
Although it is believed that a hemidesmosomal attachment (junctional epithelial
attachment) exists at the base of the implant sulcus, the first line of defense
against invading plaque and bacteria is thought to be the circular fibers
provided by keratinized gingiva surrounding the dental implant abutment. The
tissue tension provided by the circular fibers is referred to as the
Just below the junctional epithelium of the natural tooth and continuous with the connective tissue of the gingivia is the periodontal ligament. The periodontal ligament surrounds the root of the natural tooth and attaches the tooth to the bone (Figure 1).
The dental implant (unlike a natural tooth) is integrated directly to bone with no intervening periodontal ligament. This integration was termed osseointegration by Dr. Per-Ingvar Branemark. The term osseointegration can be defined as a direct structural and functional connection between ordered, living bone and the surface of a load-carrying implant.
Without a periodontal ligament the dental implant lacks the sensory advantages of a natural tooth. The dental implant is unable to adapt to occlusal trauma. Trauma can result in microfractures of the crestal bone and bone resorption. The dental hygienist must recognize warning signs such as chronic screw loosening of the screw-retained prosthesis, porcelain fracture, unseating of attachments, excessive occlusal wear, denture sores, purulence, redness, swelling and patient discomfort. Any inflammatory signs and occlusal trauma should be closely evaluated.
Fig. 1 Implant vs natural tooth
Fig. 2 Artist recreation of peri-implant suclus and magnified cells.
Peri-implant tissues around titanium abutments appear clinically similar to that of soft tissue around natural teeth. The tissue can be keratinized or non-keratinized. As with a natural tooth, the implant abutment is surrounded by a soft sulcus which is lined by crevicular epithelium. The function of the peri-implant seal is to maintain a barrier to outside contaminants. It does so by ensuring continuity in the mucosal epithelium. The importance of the seal is in its function as a barrier rather than the strength of its attachment.
Probing implants must be done with care. A gentle probing force must be used so that the tip of the probe does not penetrate the junctional epithelium and connective tissue all the way to the bone. In healthy tissue, the probe will stop at the coronal level of the connective tissue. In the presence of inflammation, the probe tip may penetrate close to the bone. Probing is critical to judge the health of an implant because as probing depth increases, the patients effectiveness in daily oral hygiene diminishes.
Fig. 3 The highly polished porcelain veneering material is generally well accepted subgingivally in a keratinized epithelial zone with little evidence of chronic inflammation present after initial healing.
| The Probing of dental
implants is often debated in implant literature. The controversy is over the
possibility of disrupting the perimucosal seal between the soft tissue and the
implant. To probe or not to probe? Plastic probes verses metal probes? In spite
of the debates, clinical experience in an implant-periodontal practice where
5,000 implants have been placed reveals no detrimental effects to implant
abutments when gentle probing is performed with a metal probe.
All implant probing should be done with care. A gentle probing force is used so that the tip of the probe penetrates the junctional epithelium but not the connective tissue. In the presence of inflammation, the probe tip may penetrate the connective tissue and come close to the bone. When inflammation is present, a radiograph is recommended to evaluate for any bone loss. For most situations, a periapical and a panoramic radiograph will be more diagnostic in assessing implant health than probe measurements alone.
For the patient's record and for legal reasons, probing should be performed after placement of the prosthesis to establish baseline data. Many clinicians believe probing should be performed at baseline, first year evaluation and annually thereafter. Others feel probing should be performed only in the presence of inflammation.
It is important to understand that probing depths differ around dental implants depending on the length of the abutment used. Deeper probe readings only indicate the presence of periodontal pathology if there is bleeding on probing, exudate and changes in probing depths over time.
What does the probe reading reveal? A deeper soft tissue wall may require the placement of a 4 mm abutment (Figure 4), and the probe readings will correspond to deeper soft tissue depths. Whenever longer implant abutments such as 4-5mm abutments are used, probe readings will naturally correspond to deeper depths.
This deeper probe reading does not indicate periodontal pathology unless:
1. There is bleeding on probing
2. Exudate is visible
3. Increased probing depth over time as compared to baseline data
4. Radiographic evidence of bone resorption
Fig. 4 Probe reading of 4 mm in a sulcus where a 4 mm abutment is in place.
A periapical radiograph taken with a strict paralleling technique can display the seating accuracy of the components of the prosthesis as well as reveal marginal bone loss around the implant (Figure 5). Due to implant placement and occlusal forces it is normal to expect 1.5 mm of bone loss in the first year of implant placement and 0.2 mm each year thereafter.
A periapical radiograph should be taken after placement of the permanent prosthesis to:
Fig. 5 Radiograph of a fully-seated prosthesis 3 years after implant placement.
Removal of deposits on the implant should be accomplished with instruments that are implant-safe. Use instruments that are unable to scratch the softer titanium implant surface. A variety of implant scalers are available which are similar to curettes. Plastic, resin, graphite and gold-tipped scalers are acceptable for implant debridement. A soft-tip plastic sleeve placed on the tip of a sonic or ultrasonic scaler (use low power and extra water) does not damage the implant surface and is clinically effective in debriding the area. Most deposits of calculus are not firmly attached to the implant due to the smooth nonporous titanium surface. The dental hygienist can effectively debribe the implant with gentle working strokes and light pressure.
Instruments not recommended include stainless steel curettes or standard ultrasonic and sonic instruments. Stainless steel instruments, standard ultrasonic and sonic instrumentation have demonstrated damage to the titanium implant abutment.
Every patient with dental implants will require a lifetime of careful evaluations and maintenance to ensure implant health and longevity. The dental hygienist plays a crucial role in the survival of implants in any practice.
The Dental Hygienist's Role In Implant Maintenance
The hygienist's role in the dental practice is well defined; however, for an implant practice the role is less defined. What is the role of the hygienist as part of the implant team? Most information that attempts to designate a role for the hygienist concentrates on technique and instrumentation for the maintenance of dental implants. Seldom is the hygienist's role as a communicator emphasized. In reality, it is most often the hygienist who delivers the first treatment to the patient. This provides the hygienist an excellent opportunity to communicate and educate the patient. After the dentist, the hygienist is the best auxiliary to expose the patient to the proposed treatment plan and to answer any questions that are of concern to the patient. Frequently, patients tend to communicate more openly with the support staff than with the dentist. This becomes an excellent time for the hygienist to address any fears and concerns the patient may express. When should the hygienist become involved with the implant team? Right from the very beginning.
Implant dentistry can be divided into four phases.
Implant dentistry is growing and gaining wide acceptance as a treatment for patients who are missing teeth. It has been accepted that members of the implant team include the surgeon, restorative dentist, and the laboratory technician, with less mention of the hygienist as an integral member of this team. With proper training and education, the dental hygienist can become an essential member of the implant team. The hygienist assumes a prominent role as evaluator, clinician and educator. This is achieved by employing skills required to ensure function, esthetics and longevity to the implant supported prosthesis.
Pictured clockwise from upper left are: End tuft brushes and sulcabrush: Pik Pocket irrigation tip; Implant Prophy Gracey 11/12 curette on top, 3i Rigid Plastic Implant Scaler, and the Implacare handle with assorted tips on the bottom; Rota-Dent (left to right), Braun Oral B, and Sonicare powered toothbrushes; Tony Riso ITS Ultrasonic scaler with plastic tips; Oral B Proxabrush (left to right), Oral B Soft Foam insert interproximal brush and Proxi-Tip; and Thornton Implant Interdental cleaner.
Instruments for implant maintenance are available from several manufacturers. The following list serves as a guide.
Le Beau R.D.H., January, Maintaining the Long-Term Health of the Dental Implant and the Implant-Borne Restoration; Compendium Oral Hygiene, Vol. 3, No. 3 1997.
Serio D.M.D., M.S., Frances G., Tools for the Maintenance Department; RDH, December 1997
Ganz D.M.D. and R.D.H., Scott D. and Sabrina, Communication: An Essential Building Block for a Successful Implant Practice-The Hygienist's Role; J. Practical Hygiene, September./ October 1993
Daniels R.D.H., Anita, The Importance of Accurate Charting for Maintaining Dental Implants; J. Practical Hygiene, September/October 1993
Surgical photography contributions:
Hilton Israelson, D.D.S. Diplomate, American Board of Periodontology, Richardson, TX
Jacqueline M. Plemons, D.D.S., M.S. Diplomate, American Board of Periodontology,Richardson,TX
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© 1999 Paula Harris