Histological assessment of hard and soft tissues surrounding a novel ceramic implant: a pilot study in the minipig.

OBJECTIVE: The aim of this study was to investigate clinical and soft/hard tissues histomorphological outcomes of a ceramic implant comparatively to a titanium implant in a minipig model. MATERIAL AND METHODS: Eighteen soft tissue level implants (9 Ceramic with ZLA(®) surface as test, and 9 titanium SLActive(®) as control, Institut Straumann, Basel, Switzerland) were randomly placed into the mandible of 6 minipigs (n = 6). Two months later, animals were sacrificed and block biopsies were obtained to assess histomorphological outcomes. Unadjusted paired comparisons, of both groups were performed using the Wilcoxon signed rank test. The Dunnett-Hsu test was used to adjust for multiple comparisons. RESULTS: All implants showed excellent integration into bone and soft tissue. The fBIC (distance implant shoulder to most coronal implant contact) and BIC% (percentage bone-to-implant contact) were for both groups; test: 3.95 mm and 85.4%; control 3.97 mm and 84.3% respectively. No difference in peri-implant mucosa height was found, however, the sulcular epithelium was significantly shorter for the ZrO2 (mean: 0.76, 95%CI: 0.46-1.06) than for the Ti (mean: 1.40, 95%CI: 1.10-1.70) (p = 0.0090). CONCLUSIONS: Within the limits of this pilot study, no difference was found between the ceramic implant with ZLA(®) surface and a titanium implant in terms of bone tissue integration. Furthermore, the epithelial attachment favoured this ceramic implant over titanium.

Dental occlusion influences knee muscular performances in asymptomatic females.

Some authors claim that occlusal appliances can enhance athletic performance. Therefore, this study investigated the influence of dental occlusion on knee muscle strength performance. Twelve healthy female subjects (mean age, 24.1 ± 3.1 years) without temporomandibular joint dysfunction participated in this study. Isokinetic quadriceps and hamstring strength were assessed in relation to 3 randomized jaw conditions: mouth closed in maximum intercuspidation without splint, mouth closed on a balanced splint which optimized contact over the dental arch, mouth closed on a piece of resin of 1 mm which created an imbalanced occlusion. Tests were performed at 60 and 240°·s in concentric and 30°·s in eccentric exertions. Concentric performances did not show any significant difference between the 3 jaw conditions (p > 0.05). In contrast, in the eccentric trials related to quadriceps performance, significant differences (p ≤ 0.05) were observed between the resin condition and the 2 other modalities (without splint or with a balanced splint). The imbalanced occlusion created by the resin component corresponded to an average decrease of 9% in eccentric peak torque. The eccentric hamstring peak torques also showed a significant difference (p ≤ 0.05) between measurements with splint and with resin (7% decrease when occlusion was imbalanced). In conclusion, among asymptomatic females, artificial imbalanced occlusion induces immediate and significant alteration of knee eccentric muscle performances. Therefore, occlusion examination should be undertaken on a regular and frequent basis for high-level athletes. Moreover, for athletes using mouthguards, muscular performance assessments should be planned with and without the dental protection.

Peri-implant soft tissues around implants with a modified neck surface. Part 1. Clinical and histometric outcomes: a pilot study in minipigs.

AIM: The goal of this study was to investigate the effect of a modified transgingival implant collar surface (acid-etched structure and hydrophilic properties) comparatively to a machined collar surface on the clinical and soft tissue integration to pure titanium implants (Ti) and titanium implants alloyed with zirconium (TiZr). MATERIAL AND METHODS: Twenty-seven implants belonging to the following groups (9 of each group): Ti modSLA with machined collar (Ti-M), Ti modSLA with machined, acid-etched surface collar (Ti-modMA) and TiZr modSLA with machined, acid-etched surface collar (TiZr-modMA) were placed in the mandible of 6 minipigs. After 8 weeks of healing, clinical measurements were taken and the sample sites were dissected and processed for histological evaluation. RESULTS: Eight weeks after implantation, the mucosa was generally located above the implant shoulder for all implant types. Histomorphometric evaluation revealed that the sulcular epithelium, junctional epithelium and the connective tissue contact were similar in the three groups. Adjusted comparisons showed that the first bone-to-implant contact was statistically more coronal for the Ti-modMA in comparison with the machined. CONCLUSION: The soft tissue dimensions around all implant prototypes were similar and not affected by the implant surface modification.

Soft tissue stability at the facial aspect of gingivally converging abutments in the esthetic zone: a pilot clinical study.

STATEMENT OF PROBLEM: The literature indicates that 0.5 to 1.5 mm of gingival recession most often occurs within the first months after implant placement or abutment connection. PURPOSE: The purpose of this pilot study was to evaluate the effect of a concave transmucosal profile on the vertical stability of soft tissues at the facial aspect of dental implants. MATERIAL AND METHODS: Fifty-four implants were placed in esthetically demanding sites in 41 patients (17 women, 24 men; age range of 23 to 62 years, mean 40.3 years; 5 smokers), primarily following a 1-stage approach. Twenty-five implants were placed immediately after extraction. Experimental concave titanium (n=49) and zirconia abutments (n=5) were used, and a provisional crown was placed at the same session. Digital photographs were made perpendicularly to the facial aspect of the teeth at abutment placement, and at 1, 3, 6, 12, 18, and 24 months, and enlarged views were subsequently analyzed by an independent examiner. Vertical changes in soft tissue levels were measured, and the definitive esthetic result was evaluated subjectively (poor to excellent). Data were analyzed with descriptive statistics. RESULTS: Twenty-four implants were evaluated at 24 months, 20 at 18 months, and 8 at 12 months. Vertical augmentation or no recession in soft tissue was observed in 87% of the situations, and in no situation was recession greater than 0.5 mm found. The gingival level remained stable at 12, 18, and 24 months. The average esthetic outcome was rated as 4.5 (very good to excellent) on a 0- to 5-point scale. CONCLUSIONS: The concave, gingivally converging abutments used in the study allowed for above-average soft tissue outcomes.

The effect of matrix bound parathyroid hormone on bone regeneration.

INTRODUCTION: Autogenous bone is the most successful bone-grafting material; however, multiple disadvantages continue to drive developments of improved methods for bone regeneration. AIM: The aim of the present study was to test the hypothesis that an arginine-glycine-aspartic acid (RGD) modified polyethylene glycol-based matrix (PEG) containing covalently bound peptides of the parathyroid hormone (PTH(1-34)) enhances bone regeneration to a degree similar to autogenous bone. MATERIAL AND METHODS: Six American foxhounds received a total of 48 cylindrical titanium implants placed in the mandible between the first premolar and the second molar. Five, respectively, 7 months following tooth extraction, implants were placed into the center of surgically created defects. This resulted in a circumferential bone defect simulating an alveolar defect with a circular gap of 1.5 mm. Four treatment modalities were randomly allocated to the four defects per side: (1) PEG-matrix containing 20 microg/ml of PTH(1-34), and 350 microg/ml cys-RGD peptide, (2) PEG alone, (3) autogenous bone and (4) empty defects. Histomorphometric analysis was performed 4 and 12 weeks after implantation. The area fraction of newly formed bone was determined within the former defect and the degree of bone-to-implant contact (BIC) was evaluated both in the defect region and in the apical region of the implant. For statistical analysis ANOVA and subsequent pairwise Student's t-test were applied. RESULTS: Healing was uneventful and all implants were histologically integrated. Histomorphometric analysis after 4 weeks showed an average area fraction of newly formed bone of 41.7+/-1.8% for matrix-PTH, 26.6+/-4.1% for PEG alone, 43.9+/-4.5% for autogenous bone, and 28.9+/-1.5% for empty defects. After 12 weeks, the respective values were 49.4+/-7.0% for matrix-PTH, 39.3+/-5.7% for PEG alone, 50.5+/-3.4% for autogenous bone and 38.7+/-1.9% for empty defects. Statistical analysis after 4 and 12 weeks revealed significantly more newly formed bone in the PTH(1-34) group compared with PEG alone or empty defects, whereas no difference could be detected against autogenous bone. Regarding BIC no significant difference was observed between the four treatment groups neither at 4 nor at 12 weeks. CONCLUSION: It is concluded that an RGD-modified PEG hydrogel containing PTH(1-34) is an effective matrix system to obtain bone regeneration.