Periodontics. Fernando Suarez

Чтение книги онлайн.

СКАЧАТЬ Jernberg et al used a constructed gauge consisting of calibrated metal strips 0.1 mm thick.²²⁴ Interestingly, O’Leary et al chose a more practical assessment by using dental floss between the interproximal embrasure and classified into them tight (definitive resistance to floss), loose (minimal resistant to floss), or open contacts (no resistance to floss).²²⁵

      Despite the inability of early studies to find a direct correlation between open contacts and periodontal destruction,^226–228 one classic study found that open contacts were directly related to food impaction, which in turn was significantly related to increased probing depths.²²⁹ However, there was no significant relationship between contact type and periodontal pocket depth. It should be noted that the subjects in that study had 80% of sites with moderate to severe gingival inflammation, indicating poor oral hygiene. This finding was confirmed in a cross-sectional study in a group of 104 subjects with 75% of anterior open contacts, demonstrating that food impaction was more frequent in open contacts (18.3%) than closed contacts (2.9%).²²⁴

      As a consequence of open contacts, plunger cusps may actively pass food into the embrasure area, causing food impaction.¹¹ Hence, more plaque accumulation is expected when plunger cusps are present, and thus adequate and frequent plaque removal is paramount to maintain periodontal integrity within embrasure areas.²³⁰ It is also important to bear in mind that teeth requiring extraction with adjacent open contacts had significantly more attachment loss than sites with closed contacts.²³¹

      MARGINAL RIDGE DISCREPANCIES

      The importance of marginal ridge relationships relies on this factor being investigated as a predisposing factor for food impaction,²³² attachment loss, and deeper probing depths.²³³ It is believed that interproximal wedging of food by a “plunger cusp” could be prevented if the integrity of proximal contacts and contour of marginal ridges are well maintained.¹¹ A study by Kepic and O’Leary evaluated marginal ridge discrepancies in posterior teeth among 100 patients. The authors found a low correlation between marginal ridge discrepancies and periodontal parameters (probing depths, attachment loss, plaque/calculus accumulation, and gingival status).²³⁴ As such, it was suggested that the presence and extent of plaque and calculus deposits are more important in determining periodontal health than uneven marginal ridge discrepancies.

      TOOTH POSITION–RELATED CONDITIONS

      Tooth crowding, crossbite, extreme overjet/overbite, and malposition are very common forms of malocclusion^235,236 and often associated with worsened periodontal conditions.^237–239 Studies evaluating the prevalence of crowding and periodontal diseases had reported values ranging between 58% and 95%, and their presence is seemingly influenced by age.^240–243

      Different definitions and grading scores have been proposed to assess crowding for periodontal purposes.^226,244,245 Van Kirk developed a scoring index to examine malalignment.²⁴⁴ Score 0 was given to an ideal alignment with no deviation from the ideal arch line projected through contact areas. Minor and major malalignment conditions were also assessed by the degree of rotation and displacement. Score 1 includes situations where rotation is less then 45 degrees and malalignment less 1.5 mm. Score 2 includes situations of rotation exceeding 45 degrees and displacement equal to or more than 1.5 mm.

      To date, it remains controversial whether tooth position–related factors exert a significant impact on the periodontium using oral hygiene as a confounding factor.^{226,246–255} Early studies showed a correlation between crowding and increased loss of clinical attachment, plaque accumulation, and gingival inflammation.^{241,256–258} On the other hand, other studies reported that crowding has no effect on periodontal health.^{226,235,240,259–261}

      Results from a cross-sectional study among 154 army recruits concluded that tooth malposition does not enhance periodontal breakdown; however, it decreases the ability for optimal oral hygiene habits.²⁴² Ultimately, Ingervall et al demonstrated that crowding did not favor plaque accumulation or extent of gingival inflammation in an experimental gingivitis model.²⁴⁵

      Because tooth crowding is not a causal agent for the initiation of periodontal disease, it must be considered in conjunction with biofilm as a contributing factor for periodontal breakdown.²⁶² Hence, individuals with poor plaque control and crowding might be more susceptible to attachment loss.

      IMPACTED THIRD MOLARS

      Generally, third molar sites are prone to plaque accumulation due to the difficulty of proper access for oral hygiene. Also, impaction of these teeth might create vertical defects on the distal surfaces of second molars.

      In a retrospective study, Kugelberg showed a significant correlation between bone healing of third molar extraction sites and patient age.²⁶³ Residual probing depths greater than 7 mm and intrabony defects exceeding 4 mm in depth were evaluated in the distal surfaces of second molars after extraction of impacted mandibular third molars. Curiously, a significant improvement of the intrabony defect depth was noted among individuals under 25 years old (Table 5-14).²⁶³

TABLE 5-14 Incidence of residual intrabony defects after third molar extraction²⁶³

      PD, probing depth.

      Later, Kugelberg et al confirmed their previous findings in a prospective study and provided evidence that periodontal healing after third molar extraction is impaired in patients over 30 years.²⁶⁴ One year postoperatively, 14% of patients aged 20 years or younger had residual intrabony defects of 4 mm or greater, while 47% of the patients aged 30 years or older had intrabony defects 4 mm or greater following removal of the impacted third molars. Thus, early removal of the impacted third molars with severe angulation and close positional relationship adjacent to the second molars will benefit the periodontal health.²⁶⁴

      RETENTION OF HOPELESS TEETH

      Several studies have investigated the potential detrimental effects of retention of a hopeless tooth. In a retrospective study with a 4-year observation period, Machtei et al defined teeth as hopeless when Class III furcation involvement or more than 50% alveolar bone loss was present.²⁶⁵ It was later demonstrated that in the absence of periodontal therapy, an annual bone loss at dentition adjacent to hopeless teeth was 10 times greater (3.12% vs 0.23%) than the teeth adjacent to the healed sockets of extracted hopeless teeth. Conversely, DeVore et al and Wojcik et al presented data of 17 hopeless teeth with a mean follow-up of 3.41 years²⁶⁶ and 8.4 years,²⁶⁷ suggesting that retention of hopeless teeth has no effect on the proximal periodontium prior to and following periodontal therapy.

      Overall, these studies demonstrated that the effect of the retention of hopeless teeth on adjacent dentition is diminished as long as active and supportive periodontal therapy is provided. Hence, Machtei revisited his previous findings and concluded that the long-term preservation of these teeth following periodontal surgery is feasible with no detrimental effects on the adjacent proximal teeth²⁶⁸ (Box 5-4).^265–268

BOX 5-4 Effect of retained hopeless teeth upon the adjacent periodontium

СКАЧАТЬ