Dimensional alterations of the facial soft and bone tissues following tooth extraction in the esthetic zone play an essential role to achieve successful outcomes in implant therapy. This prospective study is the first to investigate the interplay between the soft tissue dimensions and the underlying bone anatomy during an 8-wk healing period. The analysis is based on sequential 3-dimensional digital surface model superimpositions of the soft and bone tissues using digital impressions and cone beam computed tomography during an 8-wk healing period. Soft tissue thickness in thin and thick bone phenotypes at extraction was similar, averaging 0.7 mm and 0.8 mm, respectively. Interestingly, thin bone phenotypes revealed a 7-fold increase in soft tissue thickness after an 8-wk healing period, whereas in thick bone phenotypes, the soft tissue dimensions remained unchanged. The observed spontaneous soft tissue thickening in thin bone phenotypes resulted in a vertical soft tissue loss of only 1.6 mm, which concealed the underlying vertical bone resorption of 7.5 mm. Because of spontaneous soft tissue thickening, no significant differences were detected in the total tissue loss between thin and thick bone phenotypes at 2, 4, 6, and 8 wk. More than 51% of these dimensional alterations occurred within 2 wk of healing. Even though the observed spontaneous soft tissue thickening in thin bone phenotypes following tooth extraction conceals the pronounced underlying bone resorption pattern by masking the true bone deficiency, spontaneous soft tissue thickening offers advantages for subsequent bone regeneration and implant therapies in sites with high esthetic demand (Clinicaltrials.gov NCT02403700).
A systematic review was performed of published data on the caries-inhibiting effect of preventive measures during orthodontic treatment with fixed appliances. The purpose was to develop evidence-based recommendations about the most effective means of preventing white spot lesions in orthodontic patients. The 15 studies included were divided into four groups based on comparable preventive measures: fluoride, chlorhexidine, sealants and bonding materials. The caries-inhibiting effect of the preventive measures was expressed by the prevented fraction (PF). The overall PF of the fluoride-releasing bonding materials was 20% (SEM 0.09). This effect was, however, not statistically significant. It was impossible to calculate an overall PF for the other preventive measures, but the tendency of their caries-inhibiting effect has been described. The use of toothpaste and gel with a high fluoride concentration of 1,500–5,000 ppm or of complementary chlorhexidine during orthodontic treatment showed a demineralisation-inhibiting tendency. The use of a polymeric tooth coating on the tooth surface around the brackets showed almost no demineralisation-inhibiting effect. Many publications had to be excluded from this systematic review because of improper research designs. Future clinical trials are needed to give evidence- based advice on the optimal caries-prevention strategy.
1 May 2011 in American Journal of Orthodontics and Dentofacial Orthopedics
Objectives: To determine (1) the optimal sites for mini-implant placement in the maxilla and the mandible based on dimensional mapping of the interradicular spaces and cortical bone thickness and (2) The effect of age and sex on the studied anatomic measurements. Material and Methods: The cone beam computed tomography images of 100 patients (46 males, 54 females) divided into two age groups (13–18 years), and (19–27 years) were used. The following interradicular measurements were performed: (1) Buccolingual bone thickness; (2) Mesiodistal spaces both buccally and palatally/lingually; and (3) Buccal and palatal/lingual cortical thicknesses. Results: In the maxilla, the highest buccolingual thickness existed between first and second molars; the highest mesiodistal buccal/palatal distances were between the second premolar and the first molar. The highest buccal cortical thickness was between the first and second premolars. The highest palatal cortical thickness was between central and lateral incisors. In the mandible, the highest buccolingual and buccal cortical thicknesses were between the first and second molars. The highest mesiodistal buccal distance was between the second premolar and the first molar. The highest mesiodistal lingual distance was between the first and second premolars. The highest lingual cortical thickness was between the canine and the first premolar. The males and the older age group had significantly higher buccolingual, buccal, and palatal cortical thicknesses at specific sites and levels in the maxilla and the mandible. Conclusions: A clinical guideline for optimal sites for mini-implant placement is suggested. Sex and age affected the anatomic measurements in certain areas in the maxilla and the mandible.