Consensus conference on immediate loading: the single tooth and partial edentulous areas

PURPOSE: A consensus conference was held to determine what the parameters should be for the immediate functional loading of the single-tooth implant restoration and short-span fixed implant-supported bridgework. MATERIALS: Forty-one clinicians and researchers presented cases and situations relating to the topic. A panel then distilled questions that were presented to the audience (430) at large. Answers were gleaned to formulate a consensus. RESULTS: Ten distinct answers evolved that constituted the essence of guidelines for clinicians to be aware of when undertaking immediate loading. These guidelines are contained within the body of the text. CONCLUSIONS: Extreme caution and adherence to a universal generic protocol are suggested for clinicians who are involved with single-tooth and short-span multiple-teeth implant replacements as related to immediate loading as defined within this text.     

Terthiophene-promoted electropolymerization of 3-methylthiophene is heterogeneous electrocatalysis of polyterthiophene. A general electrocatalytic mechanism

The electrochemical oxidative polymerization of 3-methylthiophene (3MT) on platinum electrodes is favoured by the presence of previously deposited polyterthiophene (PTT) films. Cyclic voltammetry CV and single sweep voltammetry SSV were used to investigate the electrocatalytic process. The CV rate of polymer growth and the SSV electrocatalytic current increase linearly with the amount of predeposited PTT. The results rule out the previously invoked electrocatalytic promotion of 3MT polymerization by terthiophene radical cations in solution. SSV analysis with other thiophene-based polymer films (e.g. 3- and 3,4-alkylsubstituted polythiophenes) and with other thiophene-based monomers (e.g. 3,4-ethylenedioxythiophene) has shown that the electrocatalytic effect is of a general nature. The formation of a charge transfer complex between the thiophene-based monomer and the oxidized thiophene-based polymer is invoked to account for the catalytic action. The results account for the previous large and unexplained body of experimental evidence of electrocatalytic effects in the electro oxidative synthesis of conducting polymers.     

Root canal adhesive filling in dogs' teeth with or without coronal restoration: a histopathological evaluation

The purpose of this study was to evaluate in vivo the response of the periradicular tissues after endodontic treatment and root filling with Epiphany/Resilon (Penntron Clinical Technologies, LLC, Wallingford, CT) or gutta percha and new Sealapex (SybronEndo, Glendora, CA) in dogs' teeth with or without coronal restoration. Teeth without coronal restorations were used to assess the influence of continuous exposure to the oral environment on the periradicular tissues. Sixty root canals with vital pulps in three dogs were instrumented and obturated in a single session and randomly assigned to one of four groups as follows. group 1: root canal filling with Epiphany/Resilon with coronal restoration, group 2: root canal filling with Sealapex sealer and gutta percha with restoration, group 3: root canal filling with Epiphany/Resilon without restoration, and group 4: root canal filling with Sealapex sealer and gutta percha without coronal restoration. After 90 days, the animals were euthanized, and the maxillas and mandibles were removed and submitted for histologic processing. Longitudinal sections were obtained and stained with hematoxylin and eosin, Mallory's trichrome, and Brown and Brenn stains and examined under light microscopy. There were significant differences found between the four groups (p < 0.05). The results showed that roots canals filled with Epiphany/Resilon, with coronal restoration, had significantly less periradicular inflammation than roots canals filled with gutta percha and Sealapex, with coronal restoration (p = 0.021). No significant difference was observed in the intensity of inflammation between roots canals filled with Epiphany/Resilon with no restoration and roots filled with gutta percha and Sealapex with restoration (p = 0.269). Roots canals filled with gutta percha and Sealapex sealer without coronal restoration showed the greatest degree of periradicular inflammation.     

Benign paroxysmal positional vertigo following closed sinus floor elevation procedure: mallet osteotomes vs. screwable osteotomes. A triple blind randomized controlled trial

Objective: To compare mallet osteotomes with screwable osteotomes determining benign paroxysmal positional vertigo (BPPV) following the osteotome closed sinus floor elevation procedure. Materials and Methods: This triple‐blind randomized controlled trial involved 196 patients affected by edentulous atrophic ridges (107 males and 89 females; mean age 62.05±7.10; age range 49–79 years), requiring an osteotome closed sinus floor elevation procedure. Patients were randomly allocated to either a mallet‐osteotomes group (Group 1, n=98) or a screwable osteotomes group (Group 2, n=98). Two different surgeons, blind to the study, performed the closed sinus lift procedure according to the blocks allocation. A complete post‐surgical examination, including the Dix–Hallpike maneuver, was performed on 196 patients before and after surgery. The diagnosis of BPPV was supported by the existence of ageotropic nystagmus concurrent with vertigo. Results: Three patients of Group 1 (3/98–3.06%) showed a BPPV of the posterior semicircular canal omo‐lateral to the implanted side 1 or 2 days after the surgical procedure, which was promptly solved using the Epley re‐positioning maneuver. Conclusions: Preparation of implant beds with osteotome and mallet transmits percussive and vibratory forces capable of detaching the otoliths from their normal location; moreover, the patient's surgical head position favors the displacement of otoliths into the posterior semicircular canal. Implant surgeons should be aware of this possible complication following closed sinus lift procedure and patients should always be informed before undergoing surgery. To cite this article:
Sammartino G, Mariniello M, Scaravilli MS. Benign paroxysmal positional vertigo following closed sinus floor elevation procedure: mallet osteotomes vs. screwable osteotomes. A triple blind randomized controlled trial.
Clin. Oral Impl. Res. 22 , 2011; 669–672
doi: 10.1111/j.1600‐0501.2010.01998.x     

Implant therapy in irradiated patients

In this multicenter study, submerged implants were prospectively followed to evaluate their long-term prognosis in irradiated patients. In a total of 77 patients treated for oral or neck cancer, 188 implants were consecutively placed. After a healing period, the successfully integrated implants were restored with 69 removable and 38 fixed restorations. The implants cumulative survival and success rates were evaluated over a period of at least 36 months. In addition, cumulative success rates were calculated for implant subgroups divided per implant site (mandible or maxilla), radiation dosage, and the time interval between the last irradiation and implant placement. During the healing period, 20 implants did not successfully integrate, whereas 168 implants were classified as success (including both survival and success rates). The analysis of implant subgroups showed slightly more favorable cumulative success rate for mandibular implants (98.4%) compared with maxillary implants (57.1%) and clearly better success rate for a radiation dosage minor of 50-Gy doses. A time greater than 12 months as interval between last irradiation and implant placement seems not to promote better clinical results.     

The effects of viscoelastic parameters on residual stress development in a zirconia/glass bilayer dental ceramic.

OBJECTIVES: The aim of this study was to test the hypothesis that the residual stresses in a zirconia-based bilayer dental composite system can be tailored through heat treatment above and below the glass transition temperature of glass veneers. METHODS: Ceramic bilayer disc specimens were prepared from a zirconia core and a glass veneer. Each bilayer ceramic group was heat treated 40 degrees C below, 20 degrees C and 40 degrees C above and at the glass transition temperature of the glass veneer, and cooled using a fast or a slow cooling rate. Specimens were tested for flexure strength using a biaxial bending fixture. Residual stresses were calculated using a fracture mechanics approach. RESULTS: Heat treatments produced significant differences (p < or =0.05) between the mean flexural strengths of the heat treatment groups when the specimens were cooled using a fast cooling rate. However, there was not a significant difference (p >0.05) between the mean flexural strengths of the heat treatment groups when a slow cooling rate was used. Fractures initiated from the veneer surfaces of the specimens. SIGNIFICANCE: Heat treatment above and below the glass transition temperature of the veneer layer, and the cooling rate have a significant effect on the flexural strength of the bilayer ceramic laminates. The existence of residual compressive stress is the most likely reason for the observed strength increases. Residual stresses can be modified using the elastic-viscoelastic relaxation behavior of a glass veneer.     

Supratentorial Intraparenchymal Haemorrhages during Spine Surgery

Intracranial haemorrhages are rare but potentially life-threatening complications of spine surgery. Most reported cases involved subdural or cerebellar haemorrhages; supratentorial parenchymal bleeding is very uncommon. We report a 28-year-old woman who underwent resection of a thoracic Ewing''s sarcoma, and developed fatal haemorrhages around her cerebral metastases during surgery. The clinical presentations, possible pathogenesis and potential preventive measures are discussed. Patients with disseminated metastases within the neural axis are at risks of intracranial complications during spine surgery. The presence of intracranial mass lesions should be considered as a relative contraindication to intradural spine surgery.