Soft and hard tissue histologic dimensions around dental implants in the canine restored with smaller-diameter abutments: a paradigm shift in peri-implant biology

PURPOSE To evaluate the biologic width dimensions around implants with nonmatching implant-abutment diameters. MATERIALS AND METHODS Five canines had their mandibular premolars and first molars removed bilaterally and replaced with 12 implants that had nonmatching implant-abutment diameters. On one side, six implants were placed in a submerged surgical approach, and the other side utilized a nonsubmerged approach. Two of the implants on each side were placed either 1 mm above, even with, or 1 mm below the alveolar crest. Two months later, gold crowns were attached, and the dogs were sacrificed 6 months postloading. Block sections were processed for histologic and histomorphometric analyses. RESULTS The bone level, connective tissue length, epithelial dimension, and biologic width were not significantly different when the implants were initially placed in a submerged or nonsubmerged surgical approach. The bone level was significantly different around implants placed 1 mm above the crest compared to implants placed even with or 1 mm below the alveolar crest. The connective tissue dimension was not different for any implant level placement. The epithelial dimension and biologic width were significantly greater for implants placed 1 mm below the alveolar crest compared to implants placed even with or 1 mm above the alveolar crest. For five of six implant placements, connective tissue covered the implant/abutment interface. CONCLUSIONS This study reveals a fundamental change in the biologic response to implants with nonmatching implant-abutment diameters. Unlike implants with matching implant-abutment diameters, the connective tissue extended coronally past the interface (microgap). This morphologic tissue alteration represents a significant change in the biologic reaction to implant-abutment interfaces and suggests that marginal inflammation is eliminated or greatly reduced in these implant designs.

New biologic drugs: anti-interleukin therapy

nterleukins (ILs) are cytokines which are defined by their capability to convey information between leukocytes, in this way directing proliferation, activation, and migration and also regulation of the cells. Data from anti-IL treatments in systemic autoimmune diseases have shown these drugs to be beneficial and to have a satisfactory safety profile and tolerance. Recent publications of small case series suggest that several anti-IL drugs have considerable efficacy in treating otherwise refractory uveitis. Anti-IL therapy, therefore, might constitute an option for the treatment of uveitis resistant to corticosteroids, classical immunosuppressives, or tumor necrosis factor-α inhibitors. However, due to high costs and possible long-term risks, anti-IL agents should currently be reserved to selected uveitis patients and be administered only under close interdisciplinary monitorin

Relative bone width of the edentulous maxillary ridge. Clinical implications of digital assessment in presurgical implant planning

Healthy, well-structured mucosa may clinically disguise atrophic jawbone in preimplant diagnosis.

Epidermal growth factor receptor inhibitors plus chemotherapy in non-small-cell lung cancer: biologic rationale for combination strategies

Chemotherapy continues to play an essential role in the treatment of most stages of non-small-cell lung cancer (NSCLC). In fact, within the past 5 years, this role has greatly expanded into adjuvant therapy for early-stage resected disease. Likewise, agents targeting the epidermal growth factor receptor (EGFR), particularly the tyrosine kinase inhibitors gefitinib and erlotinib, have proven to be clinically active in patients with advanced-stage NSCLC. Because of these findings, it is logical to expect that combinations of these 2 classes of antineoplastic agents would prove more efficacious than either one alone. Yet 4 large randomized phase III trials of chemotherapy with or without an EGFR tyrosine kinase inhibitor in unselected patients with advanced-stage NSCLC, altogether totaling > 4000 patients, did not demonstrate improvement in clinical outcomes with the combination. Whether these negative results will be reproduced in ongoing combination studies of chemotherapy plus monoclonal antibodies directed against EGFR remain to be determined. Herein, we review recent preclinical and clinical data addressing this topic and explore the biologic rationale for developing new combination strategies based on patient selection by molecular and clinical factors, or by pharmacodynamic parameters.

Early implant placement following single-tooth extraction in the esthetic zone: biologic rationale and surgical procedures

Early implant placement is one treatment option for implant therapy following single-tooth extraction in the anterior maxilla. The surgical technique presented here is characterized by tooth extraction without flap elevation, a 4- to 8-week soft tissue healing period, implant placement in a correct three-dimensional position, simultaneous contour augmentation on the facial aspect with guided bone regeneration using a bioabsorbable collagen membrane combined with autogenous bone chips and a low-substitution bone filler, and tension-free primary wound closure. The surgical step-by-step procedure is presented with a case report. In addition, the biologic rationale is discussed.

Correlates of periodontal decline and biologic markers in older adults

BACKGROUND: There is limited information on infectious and host responses distinguishing older people with or without active periodontitis. This study measured bacterial and serum cytokine and high-sensitivity C-reactive protein (hsCRP) levels in older persons. METHODS: Elders (mean age: 67 years), whose periodontal status had declined most or least (20% worst or 20% best) over 5 years, were enrolled. Two years later, they were classified as periodontally declining (active periodontitis [AP]), if they had at least five teeth with probing depth (PD) > or =5 mm, or stable (stable periodontally [SP]), if they did not. Groups were compared with respect to demographics, PD, clinical loss of attachment, subgingival bacteria, serum hsCRP, interleukin (IL)-1beta and -6, and chronic diseases. RESULTS: Ten AP and 24 SP subjects were identified; 13% of women and 44% of men from the original sample were in the AP group (P <0.05). Most Asians were SP; most whites and all African Americans were classified as having AP (P <0.01). More AP elders had osteoporosis (P <0.01), but the AP and SP groups did not differ with respect to IL-1beta and -6 or hsCRP. Bacterial counts were higher in the AP group for Parvimonas micra (previously Peptostreptococcus micros or Micromonas micros) (7.7 x 10(5) cells versus 3.8 x 10(5) cells; P <0.05), Prevotella intermedia (25.7 x 10(5) cells versus 9.8 x 10(5) cells; P <0.01), Tannerella forsythia (previously T. forsythensis) (16.2 x 10(5) cells versus 8.0 x 10(5) cells; P <0.05), and Streptococcus mutans (6.2 x 10(5) cells versus 2.0 x 10(5) cells; P <0.01). Three risk factors were most predictive of periodontal decline: PD, osteoporosis, and being white or African American. CONCLUSION: Periodontal decline was associated with osteoporosis, ethnicity, PD, gender, serum hsCRP, and levels of four bacterial species.