Background: Aesthetics is an important aspect of modern day dentistry. Shade selection is one of the primary determinations for achieving good aesthetics in restorative dentistry. Shade selection has three parameters, namely value, chroma and hue. These can be determined by using either visual or instrumental shade guides. Previous publications have shown that teeth become darker with advancing age.1 some studies suggest that tooth value and skin colour may be inversely related. People with medium to dark skin tones have lighter teeth; those with lighter skin tones have darker teeth.2 However, other studies have found no correlation between skin tone and tooth shade.3,4 there are no studies relating tooth shade to tooth number ;sex; skin tone; age and gingival pigmentation and smoking habits.
Objectives: The objectives of this study were the following:
? To assess differences in tooth shade between the maxillary central incisor (11) and maxillary canine (13); between the mandibular central incisor (41) and the mandibular canine (43); between the maxillary central incisor (11) and mandibular central incisor (41) and between the maxillary canine (13) and the mandibular canine (43).
? To establish if there are any differences in the shades of teeth 11, 41, 13, and 43, and whether sex or age influenced the shade in any way.
? To determine if there is any correlation between the shades of teeth 11, 41, 13, 43 and patients skin tone, gingival pigmentation (non-pigmented, focal, diffuse) or smoking habits. Methods: The study sample comprised of 500 dental patients of which 305 were females and 195 were males. Their ages ranged from 18 to 81 years. These patients were divided into two age groups. Group one consisted of 291 patients, who were 35 years old and younger, Group two consisted of 209 patients older than 35 years of age. Their sex, skin tone (light, medium or dark), gingival pigmentation (non-pigmented, focal or diffuse) and smoking habits were recorded. The tooth shade of the middle third of the maxillary central incisor (11), maxillary canine (13), mandibular central incisor (41) and the mandibular canine (43), were taken, using the Vita Lumin Vacuum Shade Guide, Vita Linear 3 D-Master guide, as well as the spectrophotometer (Vita Easyshade Compact). Skin tone was recorded by using a specially designed skin tone guide; the skin tone of the inner aspect of the arm of the patient was recorded. The degree of gingival pigmentation was assessed by visual examination of the attached gingiva of the anterior part of the maxilla and mandible.
Results: The results of this study indicate that the central incisors had a lighter value than the canines, but there was no difference in value between the maxillary central and mandibular central incisors. The maxillary canine was found to be darker than the mandibular canine. A statistically significant relationship was found between tooth value and the patient s age, sex and skin tone. There was no significant relationship between gingival pigmentation and tooth value for the maxillary central incisor 11. However, there were significant relationships between tooth values for teeth 13, 41, and 43 and gingival pigmentation. There was also no significant relationship between the tooth values for teeth 13 or 43 with smoking habits of the patients, although there was a significant relationship between teeth 11 and 41 with the patients smoking habits.
Conclusion: The central incisor was lighter than the canine in both the mandible and the maxilla. The mandibular canine (43) was, however, lighter than the maxillary canine (13). There was a significant relationship between the age of patients and tooth value; older adults had darker and more yellow teeth than younger patients. Generally females had significantly lighter and less reddish teeth than males. There was a significant relationship between skin tone and tooth value in that lighter skin tone patients had darker teeth value while those with darker skin tone had lighter teeth value. Gingival pigmentation showed no association with the value of the maxillary central incisor (11), but was associated with lighter values for the maxillary canine (13), mandibular central incisor (41) and mandibular canine (43). Smoking darkened the incisor teeth, but had little or no effect on the value of canine teeth.