Strategic Considerations for the Periodontally Questionable Tooth

Dental implants quickly gained widespread acceptance because of their perceived advantage over natural teeth. They are marketed to be more predictable, cost effective, patient friendly, and esthetic than the teeth they replace.¹ However, these “benefits” are increasingly less true in light of emerging evidence.² Removing periodontally involved teeth does not address the underlying problem(s), which may lead to implant complications or failure. Treating an ailing or failing implant can result in major esthetic and functional changes.

A questionable tooth should not be immediately condemned to extraction. A strong understanding of foundational biology, risk assessment, and treatment planning will help in the decision-making process. Different regenerative materials and surgical techniques have increased tooth survival rates at costs significantly less than dental implant replacement.¹ It is worth revisiting ways to manage periodontal diseases and update the inclusion criteria for dental implants on the local and patient levels. Learning to identify when and how to save periodontally questionable teeth will increase patient satisfaction and long-term treatment success.

Local and Patient-Related Risk Factors

Before treating a specific tooth, the patient first needs to be evaluated. Periodontal prognostic schemes have shifted to consider both local and systemic risk factors that affect disease progression and maintenance.³ Certain conditions weigh more heavily on the decision to retain or extract teeth because of their destructive effects on the peri-implant biome. On a patient level, heavy cigarette smoking, autoimmune diseases, and bisphosphonate therapy have been significantly associated with peri-implant bone loss in a 5- to 10-year follow-up.²

The incidence of peri-implantitis is generally double in smokers with a 2- to 3-fold risk in developing peri-implantitis compared to healthy controls.^4,5 Additionally, the relative risk of implant failure significantly increased with smoking more than 20 cigarettes per day.⁶ Tobacco cessation should be encouraged prior to implant therapy, especially among heavy smokers. Reducing cigarette consumption to less than 10 cigarettes daily can decrease the risk of surgical complications, when quitting is not entirely possible.⁶

A similar effect is noted among patients with poorly controlled diabetes or osteoporosis. Patients with hyperglycemia or an HbA1c above 5.4% are 3.4 times more likely to have peri-implantitis.⁷ No significant differences were noted in clinical parameters compared to healthy controls in patients with osteopenia or osteoporosis taking antiresorptive medications.⁸ Patients should consult their medical provider(s) to stabilize their overall health prior to dental treatment. While these conditions considered separately are not contraindications for implant placement, a grouping of these risk factors may favor tooth retention by whatever means possible.

After a thorough workup of patients’ medical histories, their oral health status should be examined. The severity and type of periodontitis, for example, can dramatically increase the risk of implant complications and failure. In a 10-year prospective study, the implant survival rate was 97.1% for those treated for severe periodontitis. However, 66.7% of these patients eventually required antibiotic or surgical intervention.⁹ After 20 years, they were 14.6 times more susceptible to implant loss without supportive care compared to compliant, healthy controls.¹⁰ Periodontal patients who lack regular maintenance and good oral hygiene should not be viewed as implant candidates. Efforts should instead be redirected to maintain their existing dentition with dental hygiene education, routine maintenance, and periodontal therapy as needed.

The type of periodontal diagnosis can further dissuade patients from implants. Patients with what was formerly called “aggressive” or “juvenile” periodontitis have a 14-fold greater risk for peri-implantitis.¹¹ Meanwhile, over a period of 10 to 35 years, a majority of patients (78%) with this diagnosis lost only 0 to 3 teeth, when they were properly treated and maintained with nonsurgical and surgical interventions.¹²

Mean annual tooth loss was significantly reduced for patients with aggressive periodontitis who underwent flap surgery.¹³ These patients should only be considered for implants after exhausting all other options. Implant-assisted removable appliances, such as overdentures, are particularly helpful in rehabilitating terminal dentitions from these forms of periodontitis. They can be easily maintained by the patient and dental team.¹⁴

Altogether, dental implants should be reserved for periodontally and medically stable patients with supportive maintenance programs. They must be willing to adhere to the recommended recare intervals and invest in the proper hygiene aids, using them as directed. This is just as, if not more, important as the maintenance itself.

Surgical Options and Limitations for Tooth Retention

With a proper diagnosis and risk assessment, questionable teeth can be maintained using a variety of surgical procedures and materials. To start, caries or tooth fracture at or below the gingival margin, teeth with excessive occlusal loss, and teeth with inadequate interarch space benefit from functional crown lengthening.¹⁵ A minimal occlusocervical height of 4 mm for molars and 3 mm for other teeth is required for most tooth preparations.¹⁶ The occlusocervical-to-faciolingual ratio should be at least 0.4 for sufficient retention and resistance forms. These guidelines are then translated to the surgical field to remove enough tooth-supporting bone for the proposed restoration.¹⁶

Special considerations are needed for teeth in the esthetic zone. The width-to-length ratios of central incisors should remain around 78%, with about 73% for lateral incisors and canines. These vary with wear and gender.¹⁷ The central-to-lateral incisor width and lateral incisor-to-canine width should both be around 62% from the buccal view for facial harmony and symmetry.¹⁸ Tooth length and final incisal edge position should be recorded. If significant hard and soft tissue removal are required to idealize these dimensions and ratios, extraction and implant placement are preferred to avoid any mucogingival defects.

Cases of dentoalveolar extrusion or wear often lend to an interdisciplinary approach. It may not be practical, however, to perform endodontic, orthodontic, and periodontal procedures to salvage a fractured upper central incisor in a 75-year-old patient. The opposite could be said for a 14-year-old patient still undergoing craniofacial growth and development, where tooth retention is critical to prevent long-term esthetic and functional complications, including malocclusion, interdental spacing, recession, and bone loss.^1,15

In cases of strict periodontal breakdown, regenerative procedures can help form new bone, cementum, connective tissue attachment, and functionally oriented periodontal ligament.¹⁹ The success of which depends on the chronicity and morphology of the intrabony defect and periodontal phenotype. Deep (ie, > 4 mm), narrow, acutely angled, three-walled defects with thick, attached, keratinized tissue respond best to treatment.¹⁹ Probing depths and radiographs can outline the shape of these defects, so appropriate patient expectations can be set prior to surgery. Cone-beam computed tomography is more accurate in assessing molar defects but its usefulness to yield better surgical outcomes remains controversial.²⁰

Different bone grafts, membranes, and biologics can then be used to rebuild a previously diseased site after open flap debridement. In general, the use of two or more of these materials has led to significant clinical improvements, maintainable for 10 years, even in severely compromised teeth.¹⁹ In fact, periodontally hopeless teeth with attachment loss to or beyond the apex had an 88% survival rate at 10-year follow-up with mean attachment gain of 7.3 mm and residual probings of 3.4 mm. Costs were still significantly lower to retain than extract these teeth after 10 years.²¹ Finances should be discussed and compared in the decision-making process.

Questionable, hypermobile teeth are often splinted as part of periodontal therapy to better distribute occlusal stresses and improve chewing capabilities.^21,22 This is preferably done with an orthodontic wire or fiber-reinforced composite. Splinting should be considered for cases of increasing mobility or fremitus, discomfort during function, parafunctional habits, soft tissue injury, and trauma, especially in nonload-bearing regions such as the mandibular anteriors. While a recent systematic review found that splinting did not improve the survival of mobile teeth in advanced periodontitis, it was limited by a low level of evidence. The weighted mean incidence of tooth loss was still very low in this group at 8.1%.²²

In a continued effort to improve therapeutic outcomes, other, more patient-friendly technologies have been introduced. Lasers, for example, emit an intense coherent beam of monochromatic electromagnetic light that lend to a variety of intra- and extraoral uses depending on their wavelength, power density, and mode.²³ In periodontal pockets, Nd:YAG lasers remove diseased sulcular epithelium and vaporize periopathogens, such as Porphyromonas gingivalis and Tannerella forsythia.²³

A histologic study found that when used as part of the laser-assisted new attachment procedure (LANAP), true regeneration of cementum, periodontal ligament, and bone was seen in 50% of treated teeth.²⁴ However, this study had a very small sample size, treating otherwise hopeless teeth with nonreproducible results. Case selection is therefore important. LANAP can still provide definitive options for patients who cannot undergo conventional flap or regenerative surgery due to anatomical or medical limitations.

Special Considerations for MultiRooted Teeth

Multirooted teeth are complicated by other local factors. Severe, through-and-through furcation lesions respond poorly to regeneration and should be extracted.²⁵ Furthermore, molars with short, convergent root trunks and prominent root grooves or concavities have significantly reduced bone fill and attachment gain.²⁵ Generally, maxillary class II buccal and mandibular class II furcations respond most predictably to periodontal regeneration with no tooth loss and 0% to 60% furcation closure, with a majority converting to class 1 defects.²⁵ The use of a bone graft and membrane is the preferred treatment modality, especially in complex intrabony defects.²⁶

Other approaches, which are less used today, could prove viable in the right scenario. Take, for example, an 80-year-old patient with severe bone loss along the distobuccal root of #3, which serves as the distal abutment of a three-unit bridge. Knowing that a root amputation could be performed to keep the bridge intact instead of pursuing extraction, ridge preservation, or augmentation, implant placement with prior or simultaneous sinus augmentation provides tremendous patient value. No significant differences were noted between maxillary and mandibular teeth with 97% to 98% survival or root amputations.²⁷ In the mandible, hemisections can be performed on fractured or periodontally compromised molars with 84.4% survival rates.²⁷ Understanding the many nuances of when and how to save teeth will create lasting value in the patient-provider relationship and patients’ oral and overall health.

Case Report

The following case outlines the steps taken to treat a questionable dentition. A 34-year old woman presented to the Graduate Periodontics Clinic at the University of Texas Health San Antonio School of Dentistry with increasing discomfort, bleeding, and tenderness (Figures 1 through 6). The patient had a medical history significant for angina and took nitroglycerin as needed.

She first presented to an oral surgeon, who extracted her molars in preparation for conventional complete upper and lower dentures. She was concerned about losing more teeth and sought a second opinion. Her periodontal tissues were generally pink-red and loosely attached with heavy plaque, calculus, and debris noted throughout. She also presented with severe horizontal bone loss and vertical intrabony defects, and secondary occlusal trauma. Probing depths ranged from 5 to 10 mm with profuse bleeding on probing and suppuration, and clinical attachment levels ranged from 2 to 11 mm. According to the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions, she was classified as periodontitis, stage IV, generalized, grade C.²⁸

After a thorough patient evaluation and review of different techniques and materials, a comprehensive treatment plan was developed, and consents were obtained. Given the complexity and severity of periodontal breakdown for someone her age, complete blood count and metabolic panels were taken. No significant findings were noted. After ruling out any contributing systemic factors, the treatment plan included:

1. Full-mouth scaling and root planing
2. Extractions of periodontally hopeless teeth #23-26
3. Re-evaluation of clinical parameters and oral hygiene compliance
4. Fabrication of maxillary and mandibular removable dental prostheses
5. Periodontal maintenance every 3 months

Full-mouth scaling and root planing was first completed with extraction and bone grafting of #23-26. Oral hygiene instructions were reviewed in depth and at subsequent follow-ups. Periodontal re-evaluation was performed 6 weeks later. She presented with significant improvements in her at-home care and healthy clinical parameters. No further treatment was needed. She likely could have maintained her first molars based on their radiographic presentation and her response to treatment.

Definitive removable appliances were then fabricated to stabilize her occlusion. She continued in a periodontal maintenance program every 3 months. Oral hygiene techniques were reviewed and prescription fluoride toothpaste was provided to reduce the incidence of root caries and sensitivity. Two years later, she presented with continued probing depths of 2 to 3 mm with isolated, nonbleeding, 4 mm pockets around #7,8. Despite her initial presentation, she maintained most of her teeth and renewed her quality of life. With continued recare and good oral hygiene, she may be an implant candidate to assist, or even replace, her removable appliances.

Summary and Conclusions

There are clear economic, psychosocial, and clinical benefits to retaining questionable teeth. Dental implants are not the panacea they were first sold as. It is important to evaluate local and patient-related risks factors that may be detrimental to implant placement and maintenance. Efforts should be made to consider nonsurgical and surgical options to maintain teeth that would otherwise be extracted to improve patient-centered and clinical outcomes over time.

References

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From Decisions in Dentistry. January/February 2024; 10(1):13-4,16-17