Periodontal Regeneration Therapy for Compromised Anterior Teeth

An 18-year-old male patient was referred to the office with a request to extract teeth Nos. 24 and 25 and replace them with implants. Clinical and radiographic evaluations were performed (Figure 1 and Figure 2), which revealed significant bone loss in both height and width, crowding, bleeding on probing, tooth mobility, and a small soft-tissue lesion (ie, fistula) in the periapical area of teeth Nos. 24 and 25 as well as the presence of minimal keratinized mucosa supporting the mandibular anterior teeth. Despite the referral request to extract, the patient stated that he wished to preserve his teeth. Regarding the fistula, neither the patient nor the referring dentist was aware of how or when the lesion had formed, and there were no other lesions in the mouth. Endodontic and orthodontic consultations were recommended, but the patient declined to undergo an orthodontic assessment.

The endodontic evaluation revealed nonvital pulp in tooth No. 25, so endodontic treatment was performed. Unfortunately, the endodontic sealing material extended beyond the apex (Figure 3). Despite best efforts, apical extrusion of material occurs at times, and biological healing following resolution of a periapical lesion is recommended.¹ In this case, the endodontic sealing material, which leaked into the periapical lesion of tooth No. 25, could adversely impact the outcome of the endodontic-periodontal treatment.² Conventional periapical radiographs may not detect a lesion unless it is affecting cortical bone or severe in nature. In addition, periapical radiographs do not show if the buccal plate is missing or permit assessment of the extent of the lesion between the facial and lingual areas.^3,4 For these reasons, the accuracy of periapical radiography in diagnosing apical periodontitis is limited.

Primary bacterial flora, especially Actinomyces spp, are typically present in persistent apical periodontitis lesions,⁵ and Actinomyces colonization is three times more prevalent in males than in females and is typically associated with nonvital teeth.⁶ Therefore, the patient was prescribed metronidazole (250 mg) and amoxicillin (500 mg) to be taken three times a day for 2 weeks. When presented with a range of options for treatment, the patient rejected extraction and implant placement in favor of pursuing periodontal regeneration therapy to retain the teeth.

Clinical Treatment

On the day of treatment, one carpule of lidocaine (2%) with epinephrine (1:100,000) was used to achieve profound anesthesia. The area of teeth Nos. 23 through 26 had inadequate keratinized gingiva and a soft-tissue lesion approaching the apex of tooth No. 25. To access the apices of teeth Nos. 24 and 25 and the bony defect, a horizontal incision was made from tooth No. 23 to tooth No. 27 (about 2 mm to 4 mm apical to the gingival margin) using a No. 15 carbon steel scalpel blade (Sterile Disposable Scalpel Blades, Benco Dental). To minimize the risk of gingival recession and/or the loss of interdental papilla, intrasulcular incisions were rejected in favor of horizontal incisions at or slightly above the mucogingival junction. The full-thickness flap was then converted to a partial-thickness flap beyond the apex. This deepened the vestibule and enabled debridement of the bony defect, removal of the excess endodontic material, and ridge augmentation (Figure 4 and Figure 5). The lost tissue was reconstructed using freeze-dried bone allograft (Cortical bone [DN025], Maxxeus) and an absorbable membrane (Cytoplast^™ RTM Collagen, Osteogenics Biomedical) that was trimmed and fitted. To increase the zone of keratinized mucosa from the mucogingival junction to the vestibule, a free gingival graft was harvested from the left side of the palate and sutured to the recipient bed of teeth Nos. 23 through 26 using 4/0 monofilament sutures (Resorba^® Glycolon^™ Absorbable Sutures and Cytoplast^™ Non-Absorbable PTFE Sutures, Osteogenics Biomedical). The free gingival graft was significantly larger than the underlying membrane, which was only used to cover the graft material at the apical aspect of tooth No. 25, so it would receive sufficient nourishment from the site.

At the 1-year posttreatment follow-up appointment, the diagnostic images showed significant improvement (Figure 6 and Figure 7). The periodontal regeneration therapy had produced stable results, and the posttreatment radiograph suggested that approximately 8 mm of bone was gained in the occlusogingival dimension.

Images acquired at the 2-year follow-up (Figure 8 and Figure 9) demonstrate that periodontal regeneration therapy can be used to save teeth with poor prognoses when used complementarily to endodontic treatment, offering an alternative to extraction and the placement of implants. At this appointment, teeth Nos. 24 and 25 demonstrated full function with normal probing depths, no bleeding on probing, and no clinical mobility.

Implants and their restorations are subject to complications and may not necessarily last longer than natural teeth. The literature suggests that this patient, particularly because of his periodontal status and young age, would likely have ultimately experienced some implant-related complications, either biologic or prosthetic, which periodontal regeneration therapy allowed him to avoid by preserving his natural dentition.⁷ Not all teeth with a poor prognosis can be saved; however, advances in regeneration therapy can obviate the need for extraction and implants, offering a balanced approach on a case-by-case basis that includes both medical and financial considerations. When deciding between treatment options that involve extraction and implant placement or retaining the teeth by providing endodontic and periodontal therapy, relevant questions to ask include the following:

• Would dental implants offer a better prognosis and fewer complications than treating the periodontally compromised teeth?

• Is there a risk of further disease progression and subsequent tooth loss after completion of endodontic and periodontal treatments, and would dental implants preempt such a risk?

• Can the extraction of a periodontally compromised tooth and its replacement with a dental implant be justified from a financial standpoint?

• Will the patient be more satisfied with tooth extraction and an implant or with periodontal treatment that preserves the natural dentition?

• What is the long-term success rate of dental implants in the region of the mouth that the teeth to be treated are located?

• Are implants acceptable to the patient regarding the esthetics and required at-home care?

• Would implants last longer than the compromised but treated teeth, especially for younger patients who are expected to live for at least another 50 to 60 years?

When compared with the tissues surrounding the natural dentition, the tissues surrounding implants are more susceptible to plaque-associated infections, and the progression of infection has been reported to be greater and extend more apically around implants than around natural teeth.⁸ In addition, the risk for the development of peri-implantitis is greater in patients who are more susceptible to periodontitits,⁹ and the treatment of peri-implantitis is not predictable.¹⁰ Moreover, the cost of maintaining implants is much higher than the cost of maintaining natural teeth.¹¹ Research has demonstrated that biologic and technical complications of implant-supported prostheses can occur in as many as 50% of cases after 10 years¹² and that the longevity of implants does not surpass that of compromised but successfully treated natural teeth during this time span.¹³ Implant failure can be attributed to many causes, including diet, smoking, systemic or periodontal disease, parafunctional habits, oral hygiene habits, and the presence of certain microbes.⁹

To remain as conservative as possible, compromised teeth should not be replaced with implants in situations in which proper endodontic and periodontal treatment can be used to save them.¹⁴ The purpose of dental implants is to replace missing teeth, not teeth that are treatable.¹⁵ Furthermore, implant survival rates have been shown to correlate directly with the experience and specialization of the practitioners who place them.^16-19

Tooth loss is mainly the outcome of caries and periodontal disease and the manner in which these conditions are managed. In the case presented, the teeth of a young patient with severe periodontal disease were saved from extraction, avoiding the potential for long-term complications related to implant placement. Tooth retention should always be the goal because it is the more conservative, less-expensive treatment option in the long term.²⁰

Ahmad Soolari, DMD, MS
Diplomate
American Board of Periodontology
Private Practice
Gaithersburg, Potomac, and Silver Spring, Maryland