The relationship between resonance frequency analysis (RFA) and lateral displacement of dental implants: an in vitro study.

This in vitro investigation was conducted to study the relationship between resonance frequency analysis (RFA) and lateral displacement measurements of dental implants. A total of 30 implant sites were prepared in nine fresh bovine bone specimens. The bone density around each preparation was determined by using cone beam computerized tomography (CBCT) and imaging software. Dental implants were then inserted during continuous registration of insertion torque. RFA measurements were performed in perpendicular and parallel to the long axis of the specimens. The bone blocks were embedded in plaster and fixated in a specially designed rig for displacement measurements. A lateral force of 25 N was applied via an abutment perpendicular and parallel to each implant and the displacement measured in µm. In addition, a flex constant (µm N(-1) ) was calculated for each measurement. There was a significant inverse correlation between RFA and lateral implant displacement (µm) measurements and between RFA measurements and the flex constant in both perpendicular and parallel directions in bone (P ≤ 0·001). Moreover, both RFA and displacement measurements correlated with bone density (P ≤ 0·001). It is concluded that RFA measurements reflect the micromobility of dental implants, which in turn is determined by the bone density at the implant site.

Scleral fixation of a posterior chamber intraocular lens in a patient with two dislocated lens implants.

PURPOSE: To report the clinical findings and management of a case of two consecutive intraocular lenses (IOLs) dislocated into the vitreous cavity after complicated cataract surgery. METHODS: Review of clinical findings and treatment. RESULTS: A 69-year-old man sought treatment for posterior chamber IOL dislocation. The patient reported a significant loss of visual acuity in the right eye for 4 months (best-corrected visual acuity (BCVA) 20/200 in the affected eye). In the vitreous cavity two dislocated IOLs were found, complicated by a cystoid macula edema. Surgery was planned and the two IOLs were removed from the vitreous cavity. Aphakia was then corrected by means of a scleral fixated posterior chamber lens. Three months after surgery, BCVA was 20/40. CONCLUSIONS: In the absence of randomized controlled clinical trials evaluating treatment options, preoperative patient work-up should be as accurate as possible in order to reduce the risk of intraoperative and postoperative complications. In this patient, removing the two IOLs and placing a sutured-fixated posterior chamber IOL allowed resolution of the cystoid macular edema.

Bottle-cork injury to the eye: a review of 13 cases.

PURPOSE: To analyze the anatomic and functional consequences of wine-cork injury to the eye in relation to the patient's age and the type of cork and wine. METHODS: We retrospectively studied 13 patients, six women and seven men, presenting to our department with bottle-cork injury to the eye between January 1999 and June 2001. RESULTS: All patients presented with closed-globe injury according to Kuhn et al's classification. All the cases were injured by bottle corks from sparkling wine: white in ten cases and red in three. Mean visual acuity at admission was 20/100 (range, hand motion to 20/20). The most frequent early injury was anterior chamber hyphema (84.6%), followed by corneal injury (62.2%), ocular hypertension (46.1%), lens subluxation (30.8%), traumatic cataract (23.1%), and post-traumatic retinal edema (23.1%). Mean final visual acuity was 20/25; the follow-up ranged from 3 to 29 months, averaging 16.1 months. Late complications were as follows: pupil motility anomalies (38.5%), traumatic cataract (30.8%), iridodialysis (15.4%), traumatic optic neuropathy (7.7%), post-traumatic glaucoma (7.7%), and traumatic maculopathy (15.4%). Surgical treatment was necessary in two cases (15.4%). CONCLUSIONS: Bottle-cork eye injuries account for 10.8% of post-traumatic hospital admissions to our department. Most of them are due to sparkling white wine served at room temperature. There is no correlation between ocular injury and the eye-bottle distance or the type of cork.

Condylar-mandibular asymmetry, a reality.

The aim of this study is to evaluate the possibility to recognize a condylar-mandibular asymmetry through a panoramic radiograph. Results from a previous work, in which 100 skulls from the Museum of the Institute of Anatomy of the University of Pavia were studied and measured, showed the presence of asymmetry. Using the same skulls we examined the possible correlation between morphological and radiological data. We did not find out correlation's between the condylar asymmetry evaluated at the anatomical level and the radiological asymmetry which was indeed found. This is probably due to the different positioning of the jaws during the two different measuring processes. Nevertheless our results confirm the daily experience of dentistry: asymmetry of mandibular condyle can be one of the mayor causes for the asymmetry of the stomatognatic apparatus.

Effects of a beta-agonist (clenbuterol) on growth, carcass composition, protein and energy metabolism of veal calves.

Twenty-two British Friesian bull calves were used in a comparative slaughter experiment to determine the effects of a beta-agonist (clenbuterol) on body composition and energy retention. Four calves were slaughtered at 18 d of age and constituted the initial slaughter group. Of the remaining calves, eight (group A, controls) were given milk replacer only, and ten calves (groups B and C, five calves per group) were given milk replacer plus clenbuterol (0.1 and 1.0 mg clenbuterol/kg milk replacer equivalent to approximately 2 and 20 micrograms/kg body-weight respectively over the 105 +/- 3 d of the experimental period). Calves were slaughtered over the weight range 146-177 kg. Clenbuterol had no significant effect on dry matter (DM) intake, daily live-weight gain or feed conversion ratio. DM digestibility of the milk replacer was not affected by treatment. Nitrogen balance was measured on three separate occasions starting when the calves weighed approximately 60, 110 and 130 kg. N retention was increased over the experimental period in clenbuterol-treated calves, although the effect only achieved significance in calves weighing approximately 110 kg live weight (P less than 0.05). Clenbuterol (20 micrograms/kg body-weight) increased estimated mean daily N retention in the carcass of the calves from 22 to 25 g whilst N retention in the non-carcass components decreased from to 8 g/d. Effects of clenbuterol on N retention occurred mainly in skeletal muscle. Fat in both carcass and non-carcass components was reduced by treatment with clenbuterol. The total energy content of live-weight gain was reduced from 1077 to 897 MJ in clenbuterol-treated calves and mean daily heat production was estimated to increase from 23.1 in controls to 25.9 MJ/d in calves in group C. In calves of mean live weight during balance of 120 and 136 kg, clenbuterol significantly increased daily urinary creatinine excretion and in 120 kg calves N tau-methylhistidine was significantly decreased (P less than 0.05). Based on estimates of muscle mass from urinary creatinine and protein degradation from N tau-methylhistidine excretion, the fractional breakdown rate of muscle protein in clenbuterol-treated calves was only 0.66 of that in the controls when the calves weighed 120 kg.