The Relationship Between Related Parameters Of The Gingival Biotype In The Maxillary Anterior Teeth

Objectives:The objective of the study was to investigate gingival biotype related parameters in the maxillary anterior region of periodontal healthy subjects.And then, to investigate relationship between gingival thickness and bone thickness, keratinized tissue and crown wide to crown length ratio. Furthermore, relationship between gingival biotypes and gingival thickness, bone thickness, keratinized tissue, papilla height and crown wide to crown length ratio were explored.Methods:50 periodontal healthy volunteers were collected. Based on the transparency of periodontal probe through the buccal gingival margin, the gingival biotype was divided into the thick and thin groups. Keratinized tissue was measured midbuccally with the same periodontal probe. Dental stone models were made and papilla height, crown wide and crown length were measured on the stone models. Subjects were scanned by Cone-beam CT. Gingival thickness at the level of cementol-enamel junction and Bone thickness at 2mm below alveolar crest were measured on the cone-beam CT images. The relationship between gingival thickness and bone thickness, keratinized tissue and crown wide to crown length ratio were analyzed. The 5 parameters were compared between thick and thin biotype.Results:1 Mean values for 5 parameters of the maxillary anterior teeth were as follows:gingival thickness were 1.52±0.21mm,1.26±0.15mm and 1.31±0.19mm at central incisor, lateral incisor and canine. Bone thickness was 0.81±0.15mm, 0.60±0.15mm and 0.74±0.13mm at central incisor, lateral incisor and canine. Keratinized tissue was 4.35±0.72mm,4.21±0.62mm and 4.00±0.78mm at central incisor, lateral incisor and canine. Papilla height were 4.22±0.65mm,4.03±0.61mm and 4.04±0.70mm at central incisor, lateral incisor and canine. Crown wide were 7.89±0.52mm,6.191±0.44mm and 7.07±0.47 mm at central incisor, lateral incisor and canine. Crown length was 9.79±0.79mm,8.28±0.78mm and 9.26±0.91mm at central incisor, lateral incisor and canine. Crown wide to crown length ratio was 0.81±0.06, 0.75±0.07 and 0.77±0.08 at central incisor, lateral incisor and canine.2 Result of correlation analyses:positive association between gingival thickness and bone thickness was detected at central incisor, lateral incisor and canine. Association can’t be detected between gingival thickness and keratinized tissue at central incisor and lateral incisor, but partial association showed at canine. Gingival thickness and crown wide to crown length ratio was revealed no correlation at central incisor and lateral incisor, but partial association detected at canine.3 Difference analysis of 5 parameters between thick biotype and thin biotype: Statistical analysis showed significant difference for gingival thickness between thick biotype and thin biotype, as well as bone thickness. Nevertheless, no statistical significant difference for keratinized tissue, papilla height and crown wide to crown length ratio could be identified between thick biotype and thin biotype. The results were similar in central incisor, lateral incisor and canine.Conclusions:1 Study found the order of mean values for gingival thickness, bone thickness and crown wide to crown length ratio were central incisor first, then canine and the last was lateral incisor. But the order of mean values for keratinized tissue was central incisor first, then lateral incisor and the last was canine. With papilla height, the order was central incisor, then canine and lateral incisor, but the mean values had no significant statistical difference between canine and lateral incisor.2 Positive association between gingival thickness and bone thickness was detected at central incisor, lateral incisor and canine. In other words, thick gingiva always accompanied with thick alveolar bone underlying. However, association can’t be detected between gingival thickness and keratinized tissue at central incisor and lateral incisor,but partial association between gingival thickness and keratinized tissue showed at canine. Gingival thickness and crown wide to crown length ratio was revealed no correlation at central incisor and lateral incisor, but partial association detected at canine.3 Significant differences were observed in gingival thickness and bone thickness between different biotypes. Both gingival thickness and bone thickness in thick biotype are thicker than gingival thickness and bone thickness in thin biotype. Keratinized tissue, papilla height and crown wide to crown length ratio seemed to be similar between different biotypes.