Impact of Surface Chemistry Modifications on Speed and Strength of Osseointegration.

PURPOSE: To compare the bone responses of chemically modified implants using the plasma immersion ion implantation and deposition method with those of blasted implants. MATERIALS AND METHODS: The titanium implants were blasted with resorbable blasting media (RBM) and designated as controls. The ion-implanted implants were divided into two test groups, namely, calcium (Ca) and magnesium (Mg) implants. Six implants (two implants per group) were placed into the proximal tibias of 11 New Zealand white rabbits. Fluorochrome labeling was administered at 2 and 4 weeks after surgery. Resonance frequency analysis (RFA) was conducted immediately after surgery and at 6 weeks of healing. The removal torque was measured in half of the tibiae. The implants in another tibia were subjected to fluorescence analysis and histologic and histomorphometric evaluations. RESULTS: The fluorescence analysis suggested that osteoconductivity was improved in the early osseointegration stages in the Ca and Mg implants. In the cortical region, the bone-to-implant contact in the Mg implants and the bone area % in the Ca and Mg implants were higher than those in the RBM implants (P < .05). All groups demonstrated similar biomechanical strengths with respect to the RFA and the removal torque measurements. CONCLUSION: The osseointegration speed and the bone contact were positively affected by the Ca and Mg ion implantation, especially in the Mg implants, because of the synergistic effect. However, no remarkable differences were found in biomechanical strength in the later osseointegration stages.

Helical carbon and graphite films prepared from helical poly(3,4-ethylenedioxythiophene) films synthesized by electrochemical polymerization in chiral nematic liquid crystals.

Helical carbon and graphite films from helical poly(3,4-ethylenedioxythiophene) (H-PEDOT) films synthesized through electrochemical polymerization in a chiral nematic liquid-crystal (N*-LC) field are prepared. The microscope investigations showed that the H-PEDOT film synthesized in the N*-LC has large domains of one-handed spiral morphology consisting of fibril bundles. The H-PEDOT films exhibited distinct Cotton effects in circular dichroism spectra. The highly twisted N*-LC with a helical pitch of smaller than 1 µm produced the H-PEDOT film with a highly ordered morphology. The spiral morphologies with left- and right-handed screws were observed for the carbon films prepared from the H-PEDOT films at 800 °C and were well correlated with the textures and helical pitches of the N*-LCs. The spiral morphologies of the precursors were also retained even in the graphite films prepared from the helical carbon films at 2600 °C.

Electrochromism-driven linearly and circularly polarised dichroism of poly(3,4-ethylenedioxythiophene) derivatives with chirality and liquid crystallinity.

This review presents recent advances in the synthesis, electrochemical properties, and optical functions of poly(3,4-ethylenedioxythiophene) (PEDOT) derivatives embodying chirality and liquid crystallinity. Various methods for preparing the optically active and liquid crystalline (LC) PEDOT derivatives, such as (i) the introduction of chiral substituents into polymer side chains, (ii) chemical or electrochemical polymerisation by using lipid assemblies as templates, (iii) electrochemical polymerisation in asymmetric LC reaction fields, and (iv) the addition of a chiral dopant to LC-PEDOT derivatives, are discussed. Throughout the review, linearly and/or circularly dichroic electrochromism, hierarchically controlled spiral structure, and aligned morphology are demonstrated to be promising for the development of multifunctional PEDOT derivatives.

Bone response of Mg ion-implanted clinical implants with the plasma source ion implantation method.

OBJECTIVES: This study examined the bone response of magnesium (Mg) ion-implanted implants produced using a plasma source ion implantation method. MATERIALS AND METHODS: The surface characteristics were evaluated by scanning electron microscopy, Auger electron spectroscopy, X-ray photoelectron spectroscopy, and Rutherford backscattering spectroscopy. The screw-type titanium implants were treated with resorbable blasting media (RBM) and divided into one control group (RBM implants) and three test groups (Mg ion-implanted implants with different retained Mg doses). Twenty-four implants from each group were placed into the tibiae of 24 New Zealand white rabbits. After allowing 6 weeks for healing, the removal torque (RTQ) was measured and the implants were subjected to histomorphometric analysis. RESULTS: The surface roughness and surface morphology of the test groups were similar. The Mg ion-implanted implants with a 2.3 x 10(15) ions/cm(2) retained dose showed a significantly higher RTQ than the other implants. Histomorphometric analysis indicated that the bone contact of this group was superior to the other groups. CONCLUSION: The bone response of Mg ion-implanted implant showed results superior or similar to an RBM-treated implant. The optimal Mg ion concentration that induced the strongest osseointegration was approximately 9%.

Results of air caloric and other vestibular tests in patients with chronic otitis media.

OBJECTIVES: Air caloric results are supposed to be influenced by anatomic changes of the middle ear. The aims of our study were to evaluate the incidence and characteristics of abnormal air caloric results in patients with unilateral chronic otitis media and without any history of vertigo, and to compare caloric results with there of other vestibular function tests (VFTs). METHODS: Twenty five patients with unilateral chronic otitis media (COM) who were scheduled for surgery underwent VFTs preoperatively. Hearing was assessed using pure-tone audiometry and vestibular function was assessed using a set of VFTs: air caloric, head-shaking nystagmus (HSN), vibration-induced nystagmus (VIN), and subjective visual vertical (SVV) tests. RESULTS: Six patients (24%) showed pathologic canal paresis (CP) on COM-sided ears. Two patients showed pathologic CP on the contralateral side. However, both of the two showed inverted nystagmus to warm air stimulation on the COM-side and hyperactive nystagmus to cold air stimulation on the COM-side, which means that the COM-sided ear was stimulated too much. There was pathologic HSN in 12 patients (48%), pathologic VIN in 7 (28%), and pathologic SVV in 5 (20%). Overall, 20 (80%) patients showed abnormal findings through a set of VFTs. Patients with an interaural difference of bone-conduction hearing thresholds >/=10 dB tended to show more abnormal VFT results than those for whom the interaural difference of bone-conduction hearing thresholds was <10 dB. CONCLUSION: Our data show that one-fourth of patients with unilateral COM show abnormal caloric results on the COM side. However, subclinical latent vestibular imbalances were found to be common, which might be related to the gradual vestibular involvement in inflammatory processes, regardless of the caloric results. Results of a set of VFTs should be referred to when determining vestibular imbalance in patients with COM.

The Korean version of the Sniffin' stick (KVSS) test and its validity in comparison with the cross-cultural smell identification test (CC-SIT).

OBJECTIVE: The Korean Version of the Sniffin' stick (KVSS) is the first olfactory test for Koreans. Although we adopted the Sniffin' Stick, we modified it to make it more suitable for Koreans. KVSS I is a screening test, and KVSS II a more comprehensive test. The aims of this study were to apply the KVSS test and assess its clinical validity and reliability in comparison to CC-SIT. METHODS: One hundred and seventy-four healthy volunteers and 206 patients with subjective decreased olfaction participated. Each participant was tested with both the CC-SIT and KVSS tests and then the correlation between these two tests was analyzed. RESULTS: The correlation between CC-SIT and KVSS I was 0.720 (p<0.01) and 0.714 between the CC-SIT and KVSS II total scores (p<0.01). When the degree of olfaction based on the KVSS I was used, the mean CC-SIT score was 8.6+/-1.8 for normosmia, 7.3+/-2.2 for hyposmia, and 4.2+/-2.3 for anosmia. When the KVSS II total was applied, the mean CC-SIT score was 8.4+/-1.8 for normosmia, 7.3+/-2.0 for hyposmia, and 3.7+/-2.0 for anosmia. The means of the three group differed significantly in both cases (p<0.01). CONCLUSION: Thus, the KVSS test demonstrates validity and reliability for Korean in comparison with CC-SIT.

Tympanometry and CT Measurement of Middle Ear Volumes in Patients with Unilateral Chronic Otitis Media.

OBJECTIVES: The goals of the study were to compare the middle ear (ME) volumes from both normal and lesioned ears, and these ME volumes were measured by a digital image processing computed tomography (CT) program in patients with unilateral chronic otitis media, and we wanted to compare the ME volumes of the lesioned ears by comparing the ME volumes obtained by tympanometry with those ME volumes measured by the digital image processing CT program. METHODS: Forty-four patients who had unilateral chronic otitis media (COM) and contralateral normal tympanic membranes (TM) and 100 subjects with normal TMs were included in the study. The normal volumes of the external auditory canal (EAC) were measured in the normal group. The tympanometric ME volumes in the ears with a perforated TM were calculated as the difference of the tympanometric volumes measured from the both ears in patients with unilateral COM. The CT ME volumes were measured by a digital image processing program. RESULTS: The tympanometric volumes of the EACs in the ears with normal TMs were 1.4+/-0.3 mL. There were no significant differences according to gender, age and the side of the face the ear was on. The tympanometric volumes of the EAC in the normal-side ear of the patients with unilateral COM showed no significant differences when compared with those from the normal group. The ME volumes of the intact ears, as measured by CT, showed significantly higher values than those ME volumes of the lesioned ears. The ME volumes of the lesioned ears, as measured by tympanometry, showed a strong, significant linear correlation with those ME volumes calculated by CT; however, the ME volumes of the lesioned ears, as measured by tympanometry (1.5+/-1.4 mL), were significantly larger than those ME volumes measured by CT (1.1+/-0.8 mL). CONCLUSION: Our results show that chronic otitis media causes reduced ME volumes compared to those ME volumes of the contralateral normal ears. Tympanometry can provide a valuable estimation of the ME volumes in chronic ears, although it tends to overestimate the ME volumes, and especially for the ears with a larger ME volume.