Comparison between incisal embrasures of natural and prosthetically restored maxillary anterior teeth

Orthodontic treatment of traumatically avulsed maxillary central incisors with bimaxillary dentoalveolar protrusion in an adult female: a case report

BACKGROUND

Clinicians agree that obtaining and retaining good treatment results for missing maxillary central incisors owing to trauma is not easy. Management of adult patients with permanent maxillary central incisor loss who visit the clinic with high expectations for aesthetics and function pose a significant diagnostic dilemma. Therefore, esthetic and functional outcomes should be taken into consideration when deciding the proper treatment method. The treatment described in this study aimed to reestablish smile esthetics by proposing an effective multidisciplinary clinical approach that includes orthodontic-prosthetic-periodontal procedures, optimally reduced lip protrusion, center dental midlines, and establishment of stable occlusion.

CASE PRESENTATION

The patient was a 19-year-old adult female with bimaxillary arch protrusion who had been wearing removable dentures for several years since the loss of her maxillary central permanent incisors. A multidisciplinary treatment including the extraction of two mandibular primary premolars was adopted. The treatment plan consisted of orthodontic space closure by shifting the adjacent teeth towards the central incisor spaces combined with appropriate morphologic remodeling and gingival reshaping to obtain good aesthetic and functional results. The duration to complete the orthodontic treatment was 35 months. Clinical and radiographic results after treatment suggested smile harmony with an improvement in the facial profile, good function of the occlusion, and a positive effect on bone remodeling in the area of the missing incisors during orthodontic tooth movement.

CONCLUSIONS

This clinical case illustrated the necessity for using multidisciplinary methods involving orthodontic, prosthodontic, and periodontic procedures to treat an adult female patient with bimaxillary arch protrusion and long-term absence of anterior teeth due to severe trauma.

Esthetic evaluation of natural teeth in anterior maxilla using the pink and white esthetic scores

BACKGROUND

Natural teeth in the anterior maxilla are critical in determination the esthetic outcome of single implant prosthesis.

PURPOSE

The present study aimed to explore aesthetics of natural teeth in the anterior maxilla using the Pink Esthetic Score/White Esthetic Score (PES/WES) index. Additionally, inherent weak spots of natural teeth and high-risk parameters of prostheses were also considered.

MATERIAL AND METHODS

This cross-sectional study was performed by photographic analysis.

RESULTS

A total of 102 subjects and 306 teeth (the right incisor, lateral incisor and canine) were included. The grand means of the PES and WES were 12.92 and 8.75, respectively. The score of soft tissue margin, soft tissue contour and outline/volume of the crown were significantly lower than other variables. The PES and WES showed a downward trend with age. Most of the PES/WES values of the females exceeded those of the males.

CONCLUSION

The average level of natural teeth in PES and WES assessment were around 13 and 9, respectively. The soft tissue margin, soft tissue contour and outline/volume of the crown were high-risk parameters for the esthetic outcomes of implant reconstructions. Underlying factors, such as age and gender, contributed to the esthetics of natural teeth change.

Inhibition of β-catenin signaling in chondrocytes induces delayed fracture healing in mice

Appropriate and controlled chondrogenesis and endochondral ossification play fundamental roles in the fracture healing cascade, a regenerative process involved in highly coordinated biological events, including the Wnt/β-catenin signaling pathway. To examine the role and importance of this pathway in chondrocytes, we studied bone repair of closed tibias fractures in Col2a1-ICAT transgenic mice, in which the Wnt/β-catenin signaling pathway is specially inhibited in chondrocytes. Radiological, histological, and histomorphometric analyses at 7, 9, 12, 14, 21, and 28 days after fracture demonstrated the bone repairs were retarded in Col2a1-ICAT transgenic mice, due to reduced and delayed cartilage formation, chondrocyte hypertrophy, and bone generation. In addition, at 5 weeks, Col2a1-ICAT transgenic mice exhibited a weak mechanical tolerance to four-point bending. Furthermore, quantitative-PCR analysis revealed that the expression of genes associated specifically with cartilage extracellular matrix formation (collagen II, collagen X, and mmp13), bone remodeling (alp, collagen I, and osteocalcin), and vascular extravagation (vegf), and transcriptional activators involved in cartilage generation and ossification (sox9 and runx2) was decreased and delayed in the fracture sites of Col2a1-ICAT transgenic mice during healing. Collectively, these results suggest that Wnt/β-catenin signaling is critical for fracture healing, especially with respect to chondrogenesis and endochondral ossification. Thus, our study provides insight into the possible mechanisms of and therapeutic targets for improving normal facture repair and the healing of non-union fractures.