Effects of crowding in the lower anterior segment--a risk evaluation depending upon the degree of crowding.

Abstract

The aim of this study was to investigate the extent to which the anterior segment is at risk of developing disease under the influence of different types of anterior crowding and whether the degree of crowding correlates with a potential risk. A clinical examination and cast analysis taking special account of the age and gender of 125 adult patients (63 women, 62 men) were used to determine the clinical degree of abrasion and the individual incidence of tooth infractions, tooth fractures, caries, gingivitis, periodontitis and gingival recessions (WHO-OHS method), with any correlation between the incidence of disease and the respectively calculated crowding being recorded. The diagnosis of crowding was based on the segmented arch analysis proposed by Lundström [29]. Besides evaluating the total collective, a separate evaluation was performed for the age groups 18-34 years (n = 63) and > or = 35 years (n = 62). No gender-related differences in crowding were determined. Patients > or = 35 years showed significantly more crowding. An age-related increase in disease was recorded. The degree of abrasion and the individual incidence of caries did not correlate with the degree of crowding. By contrast, differences in the degree of crowding were determined in the total collective for tooth infractions (p < 0.001), tooth fractures (p = 0.004), gingival bleeding (p = 0.022), shallow periodontal pockets (p < 0.001), and gingival recessions > 3.5 mm (p < 0.001). The degree of crowding was found to correlate in the younger patients with tooth infractions (p < 0.017) and tooth fractures (p = 0.036), and in the older patients with shallow periodontal pockets (p < 0.001) and gingival recessions > 3.5 mm (p < 0.001). The incidences of disease in virtually physiologic cases of crowding (crowding < or = 2 mm, n = 31) were compared with those recorded in extreme cases of crowding (crowding > or = 5 mm, n = 30). All cases of crowding > or = 5 mm were subject to gingivitis and tooth infractions, and shallow periodontal pockets occurred three times more often and gingival recession > 3.5 mm twelve times more often. The presence of deep periodontal pockets could not be attributed to the degree of crowding. With respect to the multifactorial etiology underlying the risk of disease of the dental hard tissue and the periodontal tissues, anterior crowding > 3 mm (threshold value) as an individual "host factor" represents a cumulative risk potential for chronic inflammatory processes whose consequences are manifest only at a higher age. This gives rise to a medical treatment indication within the framework of preventive treatment strategies.