Bacterial cellulose matrix and acellular dermal matrix seeded with fibroblasts grown in platelet-rich plasma supplemented medium, compared to free gingival grafts: a randomized animal study.

PURPOSE: Mucogingival defects (MGDs), such as dental root recessions, decreased vestibular depth, and absence of keratinized tissues, are commonly seen in dental clinics. MGDs may result in functional, aesthetic, and hygienic concerns. In these situations, autogenous soft tissue grafts are considered the gold-standard treatment. This study compares the healing process of free gingival grafts (FGGs) to bacterial cellulose matrix (BCM) and human acellular dermal matrix (ADM) seeded with fibroblasts from culture supplemented with platelet-rich plasma in a rat model. METHODS: Surgical defects were made in rats, which received the following treatments in a randomized manner: group I, negative control (defect creation only); group II, positive control (FGG); group III, BCM; group IV, BCM + fibroblasts; group V, ADM; and group VI, ADM + fibroblasts. Clinical, histological, and immunological analyses were performed 15 days after grafting. Clinical examinations recorded epithelium regularity and the presence of ulcers, erythema, and/or edema. RESULTS: The histological analysis revealed the degree of reepithelization, width, regularity, and presence of keratin. The Fisher exact statistical test was applied to the results (P<0.05). No groups showed ulcers except for group I. All groups had regular epithelium without erythema and without edema. Histologically, all groups exhibited regular epithelium with keratinization, and myofibroblasts were present in the connective tissue. The groups that received engineered grafts showed similar clinical and histological results to the FGG group. CONCLUSIONS: Within the limitations of this study, it was concluded that BCM and ADM can be used as cell scaffolds, with ADM yielding the best results. This study supports the use of this technical protocol in humans.

Accelerated Fatigue Resistance of Bonded Composite Resin and Lithium Disilicate Screw-Retained Incisor Crowns with Long and Short Titanium Bases.

This study evaluates the fatigue resistance and failure mode of CAD/CAM composite resin and lithium disilicate-bonded screw-retained incisor crowns with long and short titanium bases. Sixty CAD/CAM implant restorations were fabricated using lithium disilicate (IPS e.max CAD, Ivoclar Vivadent) and composite resin (Block HC, Shofu). The central incisor crowns were bonded to a prefabricated titanium base 6 mm tall (groups: Emax6 and Shofu6; n = 15 each) or a modified abutment 4 mm tall (groups: Emax4 and Shofu4; n = 15 each). The intaglio surface of the restorations was conditioned according to the material and bonded to the titanium abutments/bases using dual-cure cement. All assembled crowns were torqued onto implants and subjected to cyclic isometric loading at the incisal edge along the implant axis. Samples were loaded until fracture. Groups were compared using Kaplan-Meier survival analysis (log rank test at P = .05). The number of mean survived cycles differed significantly, with Emax6 and Emax4 at 48,448 and 43,727 cycles, respectively, and Shofu6 and Shofu4 at 44,124 and 37,620 cycles, respectively. Post hoc tests showed similar fatigue resistance for Emax6, Emax4, and Shofu6. Shofu4 was less resistant than all other groups (P < .03). All restorations survived significantly above physiologic load limits. Lithium disilicate screw-retained incisor crowns can be used with long and short titanium bases, while it is recommended to keep a long titanium base for screw-retained composite resin crowns. The composite resin material required the full height of the abutment for optimal strength but may offer enhanced shock absorption and wear-friendliness when considering function and antagonistic wear.

Employment of U-Shape Technique at Reentry Surgery for Papillae Coronal Migration on the Rehabilitation of Anterior Single Implant: 3-Year Follow-Up Case Report.

INTRODUCTION: The rehabilitation of a maxillary single dental implant represents a great challenge at clinical practice. Harmony among the implant-supported crown and adjacent teeth is required in which concerns pink and white esthetics. The aim of the present case report is to depict a multidisciplinary treatment in which the U-shape flap technique for papillae preservation at second stage surgery was used. CASE PRESENTATION: One female patient presenting an un-rehabilitated dental implant at the left central incisor position sought treatment at the Centre of Education and Research on Dental Implants (CEPID). Alterations of color, shape, and position were observed on the anterior maxillary teeth. For proper treatment planning, radiograph, wax-up, and mock-up were performed. Second stage surgery was performed by the U-shape flap technique. A trunnion abutment was installed at the implant and a provisional subcontoured cemented crown was manufactured. Dental bleaching, feldspathic veneers, and a ceramic crown were performed. Oral hygiene instructions were recommended. Follow-up appointments were set at 1.5 and 3 years after restoration placement. After 3-year follow-up, soft tissue stability and health were preserved and papillae coronal migration around the single dental implant was observed. A complication-free treatment was reached, and patient demonstrated satisfaction towards esthetic and function. CONCLUSIONS: The use of U-shape technique at second stage surgery associated to adequate prosthetic contour improved soft tissue esthetic outcomes, while the multidisciplinary treatment planning provided adequate solutions, refining harmony between dental and implant-supported components.