Gingival Recession:Cause,Classification & Treatment

[Drsumitra]

Each patient has a different healing potential that can directly influence the response to treatment. The patient-related factors that have a negative influence on the regeneration of these lesions include smoking, stress, diabetes mellitus, acquired immunodeficiency syndrome and other acute and debilitating diseases, and the presence of multiple deep periodontal pockets. Age, gender and type of periodontal disease do not seem to play a major role in regenerative therapy (10,16).

Smoking. Epidemiological and longitudinal studies have shown an increased prevalence of periodontal disease and progression rate among smokers compared to non-smokers (17). Evidence has indicated that smokers present a less favorable response following both non-surgical and surgical periodontal therapy (18).

Various factors contribute to the deleterious periodontal effects of smoking, including alterations of the microflora and host response (17). The proposed mechanisms of the negative periodontal effects of smoking are decreased vascular flow, altered neutrophil function, decreased IgG production and lymphocyte proliferation, increased prevalence of periopathogens, altered fibroblast attachment and function, difficulty in eliminating pathogens by mechanical therapy, and negative local effects on cytokine and growth factor production (17). These deleterious effects have been related to the presence of more than 4000 toxic constituents in cigarette smoke (19).

Cigarette smoking has been associated with a reduced healing response following GTR treatment (14,19,20). Evidence indicates that the impact of smoking on regenerative therapy is more significant in the tissue maturation phase (19,20). Machtei et al. (20) recommended that when GTR is performed for class II furcation defects in smokers, anti-infective therapy should be incorporated into the treatment protocol to enhance the regenerative outcome. In that study, the experimental (anti-infective therapy) and control groups gained similar levels of tissue at membrane retrieval; however, the experimental group exhibited significantly less tissue loss between retrieval and 1-year reentry, indicating that the effect of smoking is crucial at the tissue maturation phase. Thus, while smoking prevented tissue maturation and mineralization, the anti-infective protocol enhanced these processes, resulting in a more favorable outcome. Adjunctive systemic or local antimicrobial therapy has been recommended in smokers due to evidence suggesting that subgingival pathogens are more difficult to eliminate in smokers following scaling and root planing (17).

Ah et al. (18) reported that smokers of more than 10 cigarettes a day respond less favorably to both conservative and surgical periodontal therapy than do non-smokers. Kaldahl et al. (21) noted that heavy smokers (>20 cigarettes per day) respond less favorably than light smokers (<20 cigarettes per day). It is important to note that former smokers respond to non-surgical and surgical therapy in a similar manner to those who have never smoked (17). Thus, tobacco cessation may result in better predictability and an improved regenerative response; however, the period that is required for host responses to return to normality following cessation is yet to be determined.

Stress. The influence of stress on periodontal regenerative therapy has not yet been studied. However, recently, psychological stress has been considered to be a possible risk factor for periodontal breakdown. The proposed mechanisms for the negative periodontal effects of stress include neglect of oral hygiene, changes in diet, increase in smoking and other pathogenic oral behaviors, bruxism, alterations in gingival circulation, changes in saliva, endocrine imbalances and lowered host resistance (22).

Diabetes mellitus. The diabetic’s susceptibility to periodontal disease and impaired wound healing can affect the progression of diabetes mellitus and the response to periodontal therapies such as GTR (23). Various features or events seem to be responsible for delayed wound healing in diabetic patients, such as impaired cell function, decreased tissue oxygenation, microvascular complications, increased collagenase production, deficiency in growth factors activity, deregulation of cytokines at the wound site, and decreased migration of periodontal ligament cells, which can interfere in the regenerative process (23,24).

A negative prognosis might be anticipated in patients with insulin-dependent diabetes mellitus, especially if their glucose levels vary (14). Treating furcation defects with GTR can be an option in well-controlled diabetics; however, the possibility of postsurgical complications should be considered. If complications arise because of delayed wound healing, treatment results may be less successful than expected. Thus, patients with diabetes require close supervision and frequent monitoring of the regenerated site to achieve long-term success.

Other systemic conditions. A negative prognosis might be anticipated in HIV-positive patients with other clinical or immunological deficiencies, in patients with rheumatoid arthritis, and other immune-complex diseases. High doses of irradiation in patients with a history of head and neck tumors might be detrimental to the regenerative process (14).

Presence of multiple deep periodontal pockets. GTR should be performed in patients with low levels of pathogens in the oral cavity. Barrier membranes are at risk of becoming contaminated within 3 min of intra-oral membrane manipulation in individuals with multiple deep periodontal pockets, bleeding on probing in other parts of the dentition, and high subgingival levels of putative periodontopathogens. Research has shown a negative correlation between bacterial contamination of the membrane and clinical attachment gain (25).

 

LOCAL FACTORS INFLUENCING SUCCESSFUL REGENERATION

The predictability of GTR in class II furcations is also strongly influenced by local factors, such as furcal anatomy, defect morphology, thickness of gingival tissue, and tooth mobility (8,10,26-29).

Furcal Anatomy

The furcal anatomy-related factors are the presence of cervical enamel projection, enamel pearls, root or root trunk concavities, bifurcation ridge, accessory canals, furcation entrance dimension and length of root trunk.

Cervical enamel projections and enamel pearls. Cervical enamel projections and enamel pearls may contribute to plaque accumulation and furcal invasion, hence, should be removed by odontoplasty during regenerative procedures. New attachment cannot be observed over these anatomical conditions (27).

Root concavity. Areas of root concavity also contribute to plaque accumulation and are covered by more cementum than are the adjacent convexities. This may have clinical significance because of the ability of the cementum to hold toxic bacterial products (27). Root surfaces exposed to the environment of a periodontal pocket may become hypermineralized. In addition to a direct cytotoxic effect on host cells, these surfaces may represent a poor substrate for plasma protein adsorption and subsequent fibrin adhesion (30). Thus, ultrasonic, hand and rotary instruments must be used for more effective decontamination in furcation areas, as well as the chemical conditioning of the scaled roots.

Root trunk concavities. The presence of root trunk concavities in molars, especially mandibular molars, has been reported to have possible effects on the regenerative results. Pustiglione et al. (31) and Kon et al. (32) reported that 100% of mandibular molars have root trunk concavities with a mean depth of 1.12 mm in first molars and 1.05 mm in mandibular second molars. Dunlap and Gher (33) determined the location of the first detectable buccal and lingual root concavities at 0.7 mm and 0.3 mm apical to the cemento-enamel junction, respectively, which progressively deepened to reach the furcation. The concavities of the root trunks negatively influence the results of GTR because adequate adaptation of the membranes, when placed 2 to 3 mm apical to the cemento-enamel junction, does not occur. This permits apical migration of the junctional epithelium, thus impeding the regeneration process. This was demonstrated by Novaes et al. (8), who evaluated the effect of the concavities on the regeneration of class II furcation lesions histomorphometrically in dogs. The authors suggested that a modification in the design of the membrane collars would allow more intimate adaptation of the membranes to the surface of the root trunk concavities, favoring the regeneration of periodontal tissues. In lesions treated with the modified membrane there was significant regeneration with less junctional epithelium migration and more bone regeneration. Villaça et al. (9) confirmed these results in humans and reported greater horizontal resolution of class II furcation defects treated with the modified membrane. Thus, these studies concluded that the collars of the membranes should be modified to improve regenerative results when root trunk concavities are present (8,9).

Bifurcation ridge. The bifurcation ridge is an anatomic structure formed mostly of cementum that originates from the mesial surface of the distal root, runs across the bifurcation and ends high up on the mesial root. This creates niches for plaque accumulation and has been found in 70-73% of mandibular molars. Odontoplasty should be considered in the presence of severe bifurcation ridges to ensure proper root surface preparation (27).

Accessory canal. Histologic studies have demonstrated accessory canals in the region of furcation (27). Endodontic infections can cause periodontal disease in the furcation region of molars by accessory canals and impair the healing response following GTR.

Entrance of the furcation. The architecture of the furcation entrance is an important factor for root preparation access, representing a major determinant of treatment success. Bower (34) has shown that the diameter of the furcation entrance in molars is smaller than the blade width of commonly used curettes in 58% of the furcations examined, hindering effective instrumentation of these areas. Matia et al. (35) showed that calculus removal in narrow furcations (less than 2.3 mm) is significantly better with open ultrasonic debridement than with open hand debridement; however, in wide furcations, there is no significant difference between the two approaches of calculus removal. Hence, it appears that hand instrumentation alone may not be adequate for complete root surface preparation in all furcation areas.

Length of root trunks. Molars with short root trunks are generally considered to be at higher risk for developing furcation involvement than teeth with long root trunks and are also the best candidates for tooth resection procedures (27). Bowers et al. (10) demonstrated that molars with the longest root trunks (5-6 mm) tended to respond more often with complete furcation closure following GTR therapy than teeth with shorter root trunks (100% versus 71%, respectively), although this difference failed to reach statistical significance. Hutchens (36) suggested that short root trunk length is considered to be less favorable for membrane coverage, coronal positioning and flap adaptation against the tooth. In contrast, Horwitz et al. (26) reported that long root trunk has a negative influence on the success of regenerative therapy. The results of this study indicated that long root trunks were associated with less favorable clinical horizontal probing attachment gains.

Type of tooth. Mandibular first and second molars frequently exhibit differences in root morphology and furcation access, which may affect surgical management (10). Mandibular first molars have shorter root trunks, which may account for the higher prevalence of furcation defects in mandibular first molars compared to second molars. Mandibular first molars frequently exhibit complex cementum morphology, an intermediate bifurcation ridge and intraradicular root concavities. Mandibular second molars have the longest root trunks and smaller root divergence, which may impair access for root preparation. Bowers et al. (10) demonstrated that despite comparable percentages of first and second molars with incomplete furcation closure, second molars exhibited a trend towards a higher proportion of defects with residual class II furcation. However, Machtei et al. (16) showed that first and second molars responded similarly to regenerative treatment.

The GTR procedure has a limited application for class II furcations of maxillary molars. Pontoriero and Lindhe (12) observed the largest clinical improvement in class II furcations of mandibular molars, followed by buccal class II furcations of maxillary molars and with interproximal furcation lesions exhibiting the least or no improvement. The authors reported that the reason for the different outcome of GTR in maxillary and mandibular furcation defects is most likely related to the anatomy of the defects, the presence of deep grooves in the root surface of the maxillary furcation, the limited access for root surface debridement, and the amount of remaining periodontium facing the defect. Furthermore, in interproximal furcation lesions, adaptation of the membranes is more difficult.

Defect Morphology

The clinical success of furcation therapy also appears to be strongly related to defect morphology. In a prospective study performed by Bowers et al. (10), multiple factors predictive of clinical outcome in the treatment of facial class II furcations in mandibular molars were identified: a) probing pocket depth, b) horizontal probing attachment level, c) distance of furcation roof to base of defect, d) distance of furcation roof to crest of bone, e) interproximal bone height, f) distance of bone crest to base of defect, g) root divergence, h) horizontal depth of defect, and i) furcation defect volume.

Probing pocket depth. Increases in presurgical pocket depth were associated with a significant reduction in complete furcation closure. However, Horwitz et al. (26) reported that a deep probing depth at the furcation site at baseline increases the likelihood for more favorable horizontal attachment gain in furcations. Machtei et al. (16) also demonstrated that the greater the initial pocket depth, the greater the potential for periodontal regeneration, suggesting that initial probing depth might be a useful indicator for the regenerative potential of a given site.

Horizontal probing attachment level. Increased baseline horizontal probing attachment level was associated with decreased clinical closure. Furcations with horizontal probing depths of 5 mm or greater demonstrated a lower likelihood of complete closure.

Distance of bone crest to base of defect. This measurement failed to account for differences in outcome relative to furcation closure. However, Cortellini et al. (37) reported that the depth of the infraosseous component of the defect is one of the most important factors in achieving the maximum regenerative potential. Anderegg et al. (38) also reported that the deeper the vertical component, the greater the repair.

Distance of furcation roof to base of defect. Increases in this measurement were associated with decreased clinical closure. Complete furcation closure was observed in 63% of defects with a distance of furcation roof to base of defect of 4 mm or greater. Machtei and Schallhorn (14) reported that if this measurement is lower than 4 mm and associated with defects that are mainly intra-osseous there is a better prognosis than the same measurement associated with defects that are mainly supra-osseous.

Distance of furcation roof to crest of bone. Increases in the distance of furcation roof to crest of bone were associated with a lower probability of complete furcation closure. Over 90% of defects with this measurement of 2 mm or less demonstrated complete furcation closure, compared to 67% of sites with a measurement of 3 mm or more.

Interproximal bone height. Teeth with interproximal bone height at the same level or superior to the roof of the furcation resolved with complete closure in a significantly higher percentage of cases (94% complete closure) than sites where interproximal bone was below the roof of the furcation (70% complete closure). Horwitz et al. (26) reported that, if there is bone coronal to the furcation fornix at the mesial and distal aspect of the tooth, coverage and stabilization of the membrane may be achieved with a coronally positioned flap. Under these conditions, the area of periodontal ligament available to provide cells to colonize the blood clot within the defect is larger than in the situation where the fornix is located coronal to the alveolar crest.

Root divergence. Increases in root divergence measured at crest of bone were associated with decreases in complete furcation closure. Complete furcation closure was achieved in 61% of defects with associated root divergence of 4 mm or greater, compared to 93% of defects with root divergence of 3 mm or less. However, it should be noted that furcation defects must have a root divergence sufficient to allow root preparation with hand, rotary, and ultrasonic instrumentation. Horwitz et al. (26) also demonstrated that a wide furcation entrance has a negative influence on the success of GTR therapy.

Horizontal defect depth. Furcation defects with a horizontal depth of 5 mm or greater measured at the level of the crest ofbone demonstrated a lower probability of complete closure (10). Complete furcation closure was obtained in 52% of cases, whereas defects with a horizontal depth of 4 mm or less responded with complete furcation closure in 84% of cases. Thus, in general, the findings of this study suggest that the less severe the defect, the greater the likelihood of achieving complete clinical furcation closure.

Thickness of Gingival Tissue

The amount and quality of the gingival tissue that will cover the membrane is also important. Inadequate gingival width and thin keratinized tissue should be analyzed because it can lead to gingival recession. Anderegg et al. (29) demonstrated that there is less post-treatment recession for tissue thickness greater than 1 mm than tissue thickness less than or equal to 1 mm. Thus, these authors suggest that the thickness of gingival tissue covering the membrane appears to be a factor to consider if post-treatment recession is to be minimized or avoided.

Many factors can account for this. The revascularization of any flap may be further compromised by blockage of the potential blood supply from the periodontal ligament and bone defect to the connective tissue flap by a membrane. The thicker the connective tissue, the better the potential circulatory pool and the greater the chance for flap survival. Mormann and Ciancio (39) demonstrated that flaps under tension become ischemic leading to necrosis. The blood supply in thin flaps is more likely to become compromised by tension than in thicker flaps of equal mobility. The likelihood of increased flap contraction associated with thin tissues might be magnified when placed over an ePTFE membrane, resulting in more postsurgery recession. Novaes et al. (40) reported that flaps with thin connective tissue are at greater risk for inflammation-induced postsurgery recession than thick flaps.

Tooth Mobility

Conflicting results exist concerning the effect that presurgical hypermobility has on surgical healing and, thus, on the post-therapeutic clinical outcome. Because of the scarcity of data available about the effect that tooth mobility has on periodontal regenerative therapy, the clinical relevance of mobility in regenerative therapy has not yet been elucidated. Trejo and Weltman (28) reported that intraosseous defects of teeth with Miller’s class 1 and 2 mobility responded favorably to regenerative therapy. In contrast, Cortellini et al. (41) reported that the greater the tooth mobility is at baseline, the smaller the clinical attachment level gain would be 1 year after regenerative therapy.

In clinical practice, the question of whether to splint mobile teeth prior to regenerative therapy to improve the healing outcome often arises. Further studies are needed to validate or refute the regenerative potential of splinting. Machtei and Schallhorn (14) recommended that very mobile teeth be splinted prior to GTR in class II furcation defects. Trejo and Weltman (28) recommended the splinting of hypermobile teeth to improve patient comfort during post-therapeutic healing. However, the clinician must recognize progressing tooth mobility due to trauma, teeth under premature centric occlusal contact, and teeth under traumatic excursional interferences. Such occlusal discrepancies should be removed to minimize trauma and thus tooth mobility prior to regenerative therapy