Non-prep restoration of an ankylosed incisor: a case report.

Dental restorations without tooth preparation are among today's more advanced treatment options. This article presents the case of a young man who was treated with a non-prep laminate veneer that provided 3.5 mm of incisal elongation. A Photoshop assessment and functional evaluation, as well as a wax-up and mock-up, were used during pre-prosthetic planning. A combination of pressable and feldspathic ceramics was used as a restorative material, which was applied to the tooth surface without any preparation of dental hard tissue. An ideal functional and esthetic restoration was achieved thanks to close collaboration between the patient, the dentist, and the technician.

Does the cerebral state index separate consciousness from unconsciousness?

BACKGROUND: The Cerebral State Monitor™ (CSM) is an electroencephalogram (EEG)-based monitor that is claimed to measure the depth of hypnosis during general anesthesia. We calculated the prediction probability (P(K)) for its ability to separate consciousness from unconsciousness in surgical patients with different anesthetic regimens. METHODS: Digitized EEG recordings of a previous study of 40 nonpremedicated, adult patients undergoing elective surgery under general anesthesia were replayed using an EEG player and reanalyzed using the CSM. Patients were randomly assigned to receive either sevoflurane-remifentanil or propofol-remifentanil. The study design included a slow induction of anesthesia and an episode of intended wakefulness. CSM values at loss and return of consciousness were compared. P(K) was calculated from values 30 seconds before and 30 seconds after loss and return of consciousness. RESULTS: The P(K) for the differentiation between consciousness and unconsciousness was 0.75 ± 0.03 (mean ± SE). For sevoflurane-remifentanil, P(K) was 0.71 ± 0.04. For propofol-remifentanil, P(K) was 0.81 ± 0.03. CONCLUSIONS: The ability of CSM for separation of consciousness and unconsciousness was comparable to other commercially available EEG-based indices.

The influence of injection rate on the hypnotic effect of propofol during anesthesia: a randomized trial.

OBJECTIVE: Previous studies suggested that slow injection of propofol may increase the hypnotic effect during induction of anesthesia. The aim of the present study was therefore to investigate whether injection rate of propofol has an influence on its maximum effect. DESIGN: Randomized, single-blind trial. SETTING: This study has been carried out in the operating rooms of a university hospital. An anesthesiologist and a resident performed the study with the aid of changing nursing staff. PARTICIPANTS: We investigated 99 unpremedicated patients aged 18 to 60 years with American Society of Anesthesiologists (ASA) physical status 1-3. INTERVENTIONS: Anesthesia was induced by intravenous injection of propofol (2 mg/kg). Propofol was manually injected in group 1 over a period of 5 s; in group 2 (120-s injection interval), and in group 3 (240-s injection interval), propofol was administered by an injection pump. After loss of consciousness, mask ventilation was performed with 100% oxygen. Bispectral index (BIS) was used to measure the hypnotic effect of propofol. After the decrease of BIS to the minimum value (i.e., maximum hypnotic effect) and the following increase of BIS to 60, the study period was finished and anesthesia was performed according to clinical criteria. OUTCOME MEASURES: We analyzed whether injection speed has an influence on the maximum hypnotic effect of a given dose of propofol (2 mg/kg). RESULTS: BIS(min) marks the maximum electroencephalogram (EEG) effect of the propofol bolus as measured by the BIS. The lowest mean BIS(min) was measured in group 1 (28.7 +/- 10.3). In group 2, BIS(min) was 33.0 (+/-13.9), and in group 3, BIS(min) was 36.4 (+/-11.0). There were no significant differences between group 2 and groups 1 or 3, but there were significant differences between groups 1 and 3. In group 1, BIS(min) was reached after 102.91 s (+/-44.20), in group 2 after 172.33 s (+/-29.76), and in group 3 after 274.21 s (+/-45.40). These differences were statistically significant for all comparisons. In summary, the lowest value for BIS(min) was achieved in the group with the fastest rate of propofol injection (group1, 5 s). The highest BIS(min) was obtained in the group with the slowest rate of injection (group 3, 240 s). The hemodynamic parameters were not significantly different among groups. CONCLUSIONS: The hypnotic peak effect of propofol is lower with extremely slow injection (240 s versus 5 s). For clinically usual injection rates (5 s and 120 s), there was no significant difference in propofol peak effect.

Time delay of index calculation: analysis of cerebral state, bispectral, and narcotrend indices.

BACKGROUND: On the basis of electroencephalographic analysis, several parameters have been proposed as a measure of the hypnotic component of anesthesia. All currently available indices have different time lags to react to a change in the level of anesthesia. The aim of this study was to determine the latency of three frequently used indices: the Cerebral State Index (Danmeter, Odense, Denmark), the Bispectral Index (Aspect Medical Systems Inc., Newton, MA), and the Narcotrend Index (MonitorTechnik, Bad Bramstedt, Germany). METHODS: Artificially generated signals were used to produce up to 14 constant index values per monitor that indicate "awake state," "general anesthesia," and "deep anesthesia" and smaller steps in between. The authors simulated loss of and return to consciousness by changing between the artificial electroencephalographic signals in a full-step and two stepwise approaches and measured the time necessary to adapt the indices to the particular input signal. RESULTS: Time delays between 14 and 155 s were found for all indices. These delays were not constant. Results were different for decreasing and increasing values and between the full-step and the stepwise approaches. Calculation time depended on the particular starting and target index value. CONCLUSIONS: The time delays of the tested indices may limit their value in prevention of recall of intraoperative events. Furthermore, different latencies for decreasing and increasing values may indicate a limitation of these monitors for pharmacodynamic studies.

Hyperoxic ventilation reduces six-hour mortality after partial fluid resuscitation from hemorrhagic shock.

Ventilation with 100% oxygen (Fio(2) 1.0; hyperoxic ventilation; HV) as an alternative to red blood cell transfusion enables survival in otherwise lethal normovolemic anemia. The aim of the present study was to investigate whether HV as a supplement to fluid infusion therapy could also restore adequate tissue oxygenation and prevent death in otherwise lethal hemorrhagic shock. In 14 anesthetized pigs ventilated on room air (Fio(2) 0.21), hemorrhagic shock was induced by controlled withdrawal of blood (target mean arterial pressure 35-40 mmHg) and maintained for 1 h. Subsequently, the animals were partially fluid-resuscitated (i.e., replacement of lost plasma volume) either with hydroxyethyl starch (6% HES, 200/0.5) alone (G 0.21) or with HES supplemented by HV (G 1.0). After completion of partial fluid resuscitation, all animals were followed up for the next 6 h. Five of seven animals of G 0.21 died within the 6-h observation period (i.e., 6-h mortality 71%). Death was preceded by a continuous increase of the serum concentrations of arterial lactate and persistent tissue hypoxia. In contrast to that, all animals of G 1.0 survived the 6-h observation period without lactic acidosis and with improved tissue oxygenation (i.e., 6-h mortality 0%; G 0.21 versus G 1.0 P < 0.05). In anesthetized pigs submitted to lethal hemorrhagic shock, the supplementation of partial fluid resuscitation with HV improved tissue oxygenation and enabled survival for 6 h.