Effect of hyperbaric oxygen treatment on irradiated oral mucosa: microvessel density.

The aim of this study was to evaluate the effect of hyperbaric oxygen therapy (HBOT) on microvascular tissue and cell proliferation in the oral mucosa. Twenty patients, aged 51-78 years, were allocated randomly to a treatment or a control group. All had a history of radiotherapy (50-70 Gy) to the orofacial region 2-6 years previously. Tissue samples were taken from the irradiated buccal oral mucosa before HBOT and at 6 months after treatment. In the control group, tissue samples were taken on two occasions, 6 months apart. The samples were subjected to immunohistochemistry staining: double staining with CD31 and D2-40 for microvessels, or Ki-67 for the analysis of cell proliferation. Blood vessel density and area were significantly increased after HBOT (P=0.002-0.041). D2-40-positive lymphatic vessels were significantly increased in number and area in the sub-epithelial area (P=0.002 and P=0.019, respectively). No significant differences were observed in the control group. There were no significant differences in Ki-67-expressing epithelial cells between the two groups. It is concluded that the density and area of blood and lymphatic vessels in the irradiated mucosa are increased by HBOT 6 months after therapy. Epithelial cell proliferation is not affected by HBOT.

Effect of hyperbaric oxygen treatment on oxygen tension and vascular capacity in irradiated skin and mucosa.

The aim of this study was to evaluate the effect of hyperbaric oxygen therapy (HBOT) on vascular function and tissue oxygenation in irradiated facial skin and gingival mucosa. Twenty-two patients, aged 51-90 years, were randomly allocated to a treatment or control group. All had a history of radiotherapy (50-70 Gy) to the orofacial region 2-20 years previously. Skin and mucosal perfusion were recorded with laser Doppler flowmetry (LDF). Tissue oxygenation was recorded by transcutaneous oximetry (TcPO(2)). Measurements were taken before HBOT and 3 and 6 months after a mean of 28 HBOT sessions (partial pressure of oxygen of 240 kPa for 90 min). For control subjects, measurements were taken on two occasions 6 months apart. After HBOT, blood flow in mucosa and skin after heat provocation increased significantly (P < 0.05). TcPO(2) increased significantly in the irradiated cheek (P < 0.05), but not at reference points outside the field of radiation. There were no differences between the 3- and 6-month follow-ups. In the control group, no significant changes in LDF or TcPO(2) were observed. It is concluded that oxygenation and vascular capacity in irradiated facial skin and gingival mucosa are increased by HBOT. The effects persist for at least 6 months.

Hyperbaric oxygen stimulates vascularization and bone formation in rat calvarial defects.

Hyperbaric oxygen (HBO) therapy is used to treat or prevent tissue necrosis in patients undergoing irradiation. Many such patients require reconstructive surgery, but little is known of the effects of HBO on bone vascularization and regeneration. In this study, copolymer poly(l-lactide-co-1,5-dioxepan-2-one) (poly(LLA-co-DXO)) scaffolds were implanted into critical-sized calvarial defects in Wistar rats. The animals were randomly allotted to hyperbaric or normobaric oxygen groups. The treatment group received five sessions weekly for 90 min at increased atmospheric pressure, for up to 4 weeks. Samples were retrieved at weeks 2 and 8, i.e. after a total of 10 and 20 sessions, respectively. The samples were analyzed by real-time reverse transcriptase polymerase chain reaction (RT-PCR) and histology at week 2, and radiographically and histologically at week 8. At week 2, defects treated with HBO exhibited greater numbers of cells positive for the endothelial marker CD31, up-regulated gene expression of osteogenic markers, and down-regulated expression of pro-inflammatory cytokines. At week 8, radiographic examination revealed that calvarial defects subjected to HBO exhibited a higher percentage of radiopacities than normobaric controls, and histological examination disclosed enhanced bone healing. These results confirmed that HBO treatment was effective in stimulating vascularization and bone formation in rat calvarial defects.

Reproducibility of transcutaneous oximetry and laser Doppler flowmetry in facial skin and gingival tissue.

Laser Doppler flowmetry (LDF) and transcutaneous oximetry (TcPO(2)) are non-invasive techniques, widely used in the clinical setting, for assessing microvascular blood flow and tissue oxygen tension, e.g. recording vascular changes after radiotherapy and hyperbaric oxygen therapy. With standardized procedures and improved reproducibility, these methods might also be applicable in longitudinal studies. The aim of this study was to evaluate the reproducibility of facial skin and gingival LDF and facial skin TcPO(2). The subjects comprised ten healthy volunteers, 5 men, aged 31-68 years. Gingival perfusion was recorded with the LDF probe fixed to a custom made, tooth-supported acrylic splint. Skin perfusion was recorded on the cheek. TcPO(2) was recorded on the forehead and cheek and in the second intercostal space. The reproducibility of LDF measurements taken after vasodilation by heat provocation was greater than for basal flow in both facial skin and mandibular gingiva. Pronounced intraday variations were observed. Interweek reproducibility assessed by intraclass correlation coefficient ranged from 0.74 to 0.96 for LDF and from 0.44 to 0.75 for TcPO(2). The results confirm acceptable reproducibility of LDF and TcPO(2) in longitudinal studies in a vascular laboratory where subjects serve as their own controls. The use of thermoprobes is recommended. Repeat measurements should be taken at the same time of day.

Salivary gland and temporomandibular joint involvement in rheumatoid arthritis: relation to disease activity.

OBJECTIVES: To study temporomandibular joint (TMJ) involvement, salivary gland dysfunction and oral mucosal lesions in rheumatoid arthritis (RA), and to investigate the relationship to general disease activity. SUBJECTS AND METHODS: The TMJ dysfunction index (D(i)), mean salivary flow and disease activity score (DAS28), were calculated for 50 RA-patients, and 23 non-RA patients (controls). RESULTS: Median D(i) was 5.5 (range: 0-21) for the RA-patients compared with 2.0 (range: 0-9) for the controls (P < 0.0001). Pain on movement of the TMJ (P = 0.015), muscular pain (P = 0.006), TMJ pain (P = 0.019) and D(i) as a total (P = 0.009), significantly correlated with DAS28. Mean resting whole saliva (RWS) flow was 2.6 (s.d. 2.4) ml per 15 min for the RA-patients and 4.5 (s.d. 3.0) for the controls (P = 0.003). RWS correlated positively with haemoglobin (P = 0.021) and negatively with Westergren erythrocyte sedimentation rate (ESR) (P = 0.029). No major differences in frequency of oral mucosal lesions were seen between RA-patients and controls. CONCLUSIONS: Higher frequency of TMJ and salivary gland dysfunction in RA-patients compared with controls has been demonstrated. RA disease activity is associated with hyposalivation and TMJ dysfunction.

Nonsubmerged implants in the treatment of the edentulous lower jaw: a 5-year prospective longitudinal study of ITI hollow screws.

BACKGROUND: Although most implant systems have been designed for a two-stage surgical technique, a one-stage surgical technique has always been advocated for the ITI Dental Implant System (Straumann AG, Waldenburg, Switzerland). A new generation of ITI implants was presented in 1988 and included a hollow cylinder, a hollow screw, and a solid screw. PURPOSE: The goal of this study was to evaluate the one-stage surgical technique in connection with the ITI hollow screw in a longitudinal study over 5 years. MATERIALS AND METHODS: Forty-six patients with edentulous lower jaws were supplied with ITI hollow-screw implants. Patients who requested an overdenture (n = 18) had four implants inserted; those who requested a fixed bridge (n = 28) had five to six implants. The patients have been followed annually for 5 years. There was a dropout of three patients (6.5%); one patient did not want to cooperate, one moved from the area, and one was deceased. The clinical examinations included bridge removal for evaluation of the individual implant stability in connection with the 1-, 3-, and 5-year examinations. Radiographic examinations were performed with intraoral radiographs and the long-cone technique. RESULTS: The survival rate after 5 years was 95.7%. The success rate (in which implants undergoing treatment of peri-implantitis were not counted as successes) was 91.4%. The mean marginal bone loss between the baseline and the 1-year examination was 0.1 mm and between the 1- and 5-year examinations was 0.1 mm. These changes in marginal bone level were not significant. CONCLUSIONS: The success rate of ITI hollow-screw implants in the edentulous mandible was 91.4% after a 5-year observation period. There was no significant change in mean bone level between the loading of the implants and the 5-year examination. Peri-implantitis was diagnosed in three patients with poor oral hygiene, and it affected six implants. Five of these failed in spite of treatment.

Nonsubmerged implants in the treatment of the edentulous upper jaw: a prospective clinical and radiographic study of ITI implants--results after 1 year.

BACKGROUND: A new generation of ITI implants, including a hollow cylinder, a hollow screw, and a solid screw, was described in 1988. Currently, the solid screw is the main alternative. PURPOSE: The aim of this study was to gain further clinical documentation of ITI solid-screw implants used in the edentulous upper jaw. This is a report 1 year after loading. MATERIALS AND METHODS: Twenty-eight patients with edentulous upper jaws (mean age, 57 yr) were supplied with four to eight ITI solid-screw implants in the upper jaw. In total, 167 implants (3.3 and 4.1 mm in diameter) were inserted. The implants were loaded about 7 months postoperatively. All patients were supplied with fixed screw-retained bridges. RESULTS: Twelve implants failed: 10 prior to loading and 2 after. Overall implant survival rate was 92.8%. Three of the five patients with implant loss were smokers. Signs of peri-implantitis were found in seven patients, affecting 12 implants. Mean marginal bone level at the loading of the implants (7 months after insertion) was situated 4.7 mm from the reference point of the implant. There was no significant change between loading and the 1-year examination. However, at several implants, the bone level at baseline was situated far apical of the reference point, indicating a bone loss before loading. CONCLUSIONS: The ITI screw implants, used in the edentulous upper jaw, had a survival rate of 92.8%. Mean bone loss between loading and the 1-year examination was 0.1 mm. Some implants had a bone level indicating a significant bone loss before loading. Peri-implantitis was found at about 7.2% of the implants inserted and at 25% of the failing implants.

The mini bottle brush--a new fastening device in cancellous bone.

A new design for bone implants, the bottle brush, was recently presented in a pilot study on marrow cavities in the femur of rabbits. In this study, the concept is further evaluated on a mini bottle brush. The fixture, 5 x 7 mm, with an implant shaft made of CP-titanium and bristles of nylon coated with sputtered titanium, was inserted into the cancellous bone of the medial femoral condyle in 15 adult rabbits. The titanium fixture was compared with a similar brush without the titanium sputtered surface. The animals were sacrificed after 4 months and the quantity and quality of bone integration were evaluated with pull-out tests and histological examination. In both parameters, the values were significantly higher for the titanium-sputtered brushes, with removal forces similar to titanium cylinders of the same size and with a bone-to-metal contact area of about 50%.

Non-submerged implants in the treatment of the edentulous lower jar. A 2-year longitudinal study.

Non-submerged ITI Bonefit implants (ITI Dental Implant System) were inserted in edentulous lower jaws of 46 patients. The patients were provided with either a fixed prosthesis or an overdenture, and has been followed during a 2-year-period. At the 1-year examination, the suprastructures were removed permitting test of the individual implant stability. Radiographic examinations were performed in connection with the loading of the implants and at the 1-year examination. In total 216 implants were inserted. 4 implants were lost before loading and 4 during the 2nd year of function, which gives a survival rate after 1 year 98% and after 2 years of 96%. The mean marginal bone loss during the first year of function was 0.1 mm. However, the marginal bone changes had a high degree of variation and four implants showed a severe bone loss. The intention is to follow this patient group with annual examinations during 5 years.

A bone tissue integrated single fibre laser Doppler flowmeter probe.

Laser Doppler Flowmetry was developed and evaluated mainly for measuring blood flow in exposed or superficial tissue layers like skin. Results showed large variation coefficients between juxtaposed skin sites with apparently homogeneous blood perfusion. Spatial differences in blood flow as well as anatomical differences probably explain the obtained results. Vasomotion, hereto only discovered with a microscopic technique, was recorded and evaluated for the first time. Similar results had been obtained in previous bone perfusion studies. The LDF technique has also been used extensively for skin irritancy tests and microvascular effects of vasoactive substances and drugs. An in vivo model in calibrating LDF quantitatively showed a linear relationship between LDF output signal and total blood flow in the range 0-300 ml min-1 100 g-1. This quantitative calibration is however tissue specific. Most tissues of interest are not superficial. The single fibre LDF provides additional power in studying deep tissue physiology and trauma-induced changes in regulation of microvascular perfusion. Furthermore long-term studies require implantable and biocompatible probes and this could be fulfilled using the SFLDF technique in combination with a tissue-integrated titanium probe. Implantation of the titanium probes initially creates some trauma to the vascular bed in the bone marrow but almost none in the opposite cortical bone layer. The healing process enhances the blood perfusion during the first weeks. The increased perfusion can be due to different parameters such as angiogenesis. The histological findings support this hypothesis. This gives preference to the tissue-integrated probe where interference with the tissue should be avoided. The integrated probe technique has only been evaluated in bone tissue. Modification of the probe shape and dimension, however, would make it suitable for other tissues as well.

Tyrosine kinase activities in normal and neoplastic epithelia tissue of the human upper aero-digestive tract.

Tyrosine kinase activity was studied in the crude cytosolic and particulate fraction of normal mucosa and squamous cell carcinomas of the upper aero-digestive tract. In the presence of exogenously added phosphorylation substrate (Glu,Tyr4:1), the cytosolic tyrosine kinase activity was 6-fold higher in tumors compared to normal mucosa (p = 0.001), and in the particulate fraction the increase was 8-fold in tumors compared to normal mucosa. Different proposed tyrosine kinase inhibitors, including genistein, quercetin and the alpha-cyanocinnamide ST 638, were tested for their ability to inhibit phosphorylation of the synthetic tyrosine phosphorylation substrate. Phosphorylation of Glu,Tyr4:1 in tumors (cytosolic fraction) was reduced to 77.8 +/- 8.7% of the control value by 10 microM ST 638 (p less than 0.05), and to 50.7 +/- 10.4% by 100 microM quercetin (p less than 0.01). In normal mucosa (cytosolic fraction) the corresponding values were 41.7 +/- 16.6% in the presence of 10 microM ST 638 (p less than 0.05) and 32.1 +/- 5.8% in the presence of 100 microM quercetin (p less than 0.05). These inhibitors had no effect on the tyrosine kinase activity in the particulate fractions. Phosphorylation of endogenous proteins in the crude cytosolic fraction was evaluated by SDS-polyacrylamide gel electrophoresis after alkali treatment of the gels. Autoradiography of the gels treated in this manner revealed bands corresponding to phosphorylated proteins with apparent molecular weight of 18, 23, 37-38, 42-44 (double band), 53-55 (double band), 61 and 92-94 (double band) kD. Quercetin (100 microM) markedly reduced the phosphorylation of these proteins, while no effect of ST 638 could be seen. Heparin (20 micrograms/ml) stimulated the phosphorylation of three proteins with apparent molecular weight of 39 and about 72 kD, respectively, and inhibited the phosphorylation of 2 proteins with molecular weight of 92 and 53 kD in tumors. These features were observed in both tumors and normal tissue, with the exception that heparin only stimulated the 72 kD band in normal mucosa and that the phosphorylation was markedly higher in tumors. In summary, our results show an increased tyrosine phosphorylation in squamous cell carcinomas of the upper aero-digestive tract compared to normal oral mucosa. These differences and their origin might be of vital importance in the regulation of events leading to malignant transformation.

Protein phosphorylation substrates in normal and neoplastic squamous epithelia of the human upper aero-digestive tract.

Protein phosphorylation was studied in crude and in protein kinase C (Pk-C)-enriched preparations from squamous cell carcinomas and normal mucosa of the human upper aero-digestive tract. In crude soluble preparations from neoplastic mucosa we found a 5-fold higher basal endogenous phosphorylation when compared to normal mucosa. In particulate fractions the increase was 3-fold. SDS-PAGE and autoradiography of phosphorylated proteins in crude soluble tumor extracts showed bands corresponding to proteins with apparent molecular weights of 18, 37, 40-42, 52, 60, 62 and 90 kDa. In normal mucosa the phosphorylation of these proteins was very low or absent, except for the proteins with molecular weights of 40-42 and 52-55 kDa. Addition of Ca2+ or Ca2+/phospholipids to the reaction mixture caused phosphorylation of additional proteins with apparent molecular weight of 45-50 kDa in soluble preparations of tumors. Cyclic AMP or cGMP had no significant effect on the phosphorylation of endogenous proteins. In the partially purified, Pk-C-enriched fractions the phosphorylation in the presence of Ca2+/phospholipids was distinctly higher in tumors when compared to the phosphorylation observed in normal mucosa, and some phosphorylation substrates were detected only in tumor tissue. In order to find out whether the elevated basal phosphorylation was due to an endogenous activation of protein kinases, different inhibitors of serine/threonine protein kinases were tested. These inhibitors included: heat-stable cyclic AMP-dependent protein kinase (Pk-A) inhibitor, Pk-A inhibitor peptide (Wiptide), heparin and the Pk-C inhibitors peptide 19-36 and H-7. None of these inhibitors had any significant effect on the basal phosphorylation. In conclusion, our results show the existence of endogenous phosphorylation substrates in human squamous cell carcinomas from the upper aerodigestive tract, and indicates that there is a significantly higher basal and Pk-C specific phosphorylation of endogenous substrates in tumors compared to normal mucosa. This may be of importance for the transformation and altered growth regulation in epithelial tumors.

Protein kinase activities in neoplastic squamous epithelia and normal epithelia from the upper aero-digestive tract.

In the present study the activities of three different protein kinase were determined in squamous cell carcinoma from the upper aero-digestive tract, and compared with the activities in normal oral mucosa. The protein kinases investigated are: a) cAMP-dependent protein kinase; b) cGMP-dependent protein kinase, and c) casein kinase II. The basal protein kinase activity, when histone IIa was used as substrate, was about 3-fold higher in tumors, as compared to normal mucosa, in the soluble fraction (32.0 +/- 4.2 and 10.9 +/- 2.4 pmol 32P/mg prot. X min, respectively). In the particulate fraction the basal protein kinase activity was about 9 times higher in tumors as compared to normal mucosa (19.4 +/- 5.2 and 2.1 +/- 0.3 pmol 32P/mg prot X min, respectively). The protein kinase activity in the presence of cyclic nucleotide (cAMP/cGMP) minus the basal protein kinase activity was taken as the cAMP- and the cGMP-dependent protein kinase activity, respectively. Maximal protein kinase activity was obtained in the presence of 0.5 microM of cyclic nucleotide both in squamous cell carcinoma and normal mucosa. In the cytosolic fraction the cAMP-dependent protein kinase activity was 33.9 +/- 13.0 pmol 32P/mg prot. X min in tumors, and 28.2 +/- 5.8 pmol 32P/mg prot. X min in normal tissue, after stimulation with 0.5 microM cAMP. The cGMP-dependent protein kinase activity was 5-10% of the cAMP-dependent protein kinase activity, and no concentration-dependent stimulation with cGMP was seen. The cGMP-dependent protein kinase activity in the presence of 0.5 microM cGMP was 2.4 +/- 1.3 and 1.8 +/- 0.6 pmol 32P/mg prot. X min in tumors and normal mucosa, respectively. Casein kinase II activity was determined only in the cytosolic fraction and was found to be 3-fold higher in tumors as compared to normal mucosa (31.8 +/- 5.2 and 8.6 +/- 3.5 pmol 32P/mg prot X min, respectively). This study shows a general increase in histone phosphorylation and casein kinase activity in neoplastic squamous epithelia compared to normal epithelia. No evidence for an increase in cyclic nucleotide dependent protein kinase activities in neoplastic squamous epithelia was found. This study thus supports the idea that phosphorylation/dephosphorylation reactions may play an important role in the control of cell growth, differentiation and proliferation.

Titanium-coated hollow screw and reconstruction plate system (THORP) in mandibular reconstruction.

Clinical results are presented which have been obtained from mandibular reconstruction with the Titanium-coated Hollow Screw and Reconstruction-Plate system (THORP) in 7 selected patients. In 3 of the patients primary bone grafting was performed with simultaneous implantation of titanium fixtures for dental reconstruction. The reconstruction-plates have shown excellent functional stability with no failures, such as loosening of screws, within an observation period up to 2 1/2 years. The system was submitted to immediate full functional loading despite the limited number of 2-3 fixation screws for each end of the plate. Among several technical advantages of the system are the possibility of lingual plate application and reconstruction with a three-dimensionally free, adjustable condylar prosthesis.

Surgical procedures for reconstruction of the lower jaw using the titanium-coated hollow-screw reconstruction plate system: bridging of defects.

The various advantages rendered by the system described enable primary as well as long-term functional stability even in cases in which conventional systems would be insufficient. The evaluation of 49 cases managed in Bern and Sweden confirm the efficiency of this reconstruction system.

Bone-plates for stabilizing Le Fort I osteotomies.

16 adults were treated by inferior repositioning of the maxilla. Miniaturized plates were used for stabilizing the jaw in its new position. No interpositional bone grafts were used but the osteotomy spaces were covered by strips of cancellous iliac bone. Healing was uncomplicated. Retrospective cephalometric study of the results of treatment showed a mean frontal vertical relapse of about 20% (range 0-100%). The relapse occurred during the early postoperative period. No linear correlation was found between the amount of vertical repositioning and the anterior vertical relapse. We consider that the mini-plate technique is more advantageous than previous methods.

Auger electron spectroscopic studies of stainless-steel implants.

Auger electron spectroscopy together with scanning electron microscopy has been used to study the interface between stainless-steel implants and human tissue. The thickness and nature of the oxide layer on the implants have been found to depend on the location of the implants in the body. Before implantation, the oxide layer is about 50 A thick, consisting mainly of chromium oxide. For implants located in cortical bone the thickness of the interfacial oxide layer remains unaffected, while it increases by a factor of three to four on samples located in bone marrow. In both these cases calcium and phosphorus are incorporated in the oxides. Implants located in soft tissue have an interfacial oxide layer with a thickness of about one and one-half times that on an unimplanted sample. On these samples, calcium and phosphorus are not found, but occasionally sulfur is found in the oxide layer. All these samples originated from the oral region of the body; the reason for this finding, however, is not known at present time. The interactions between the implants and human tissues resulting in the observed changes of the implant surfaces are discussed in terms of oxygen pressures and metabolic activity.