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Smedberg JI, Conrad J, Rudolfsson T, Lindinger A, Moberg LE. A 25-Year Retro-prospective Study on Prosthetic Rehabilitation with Bonded Ceramics of Patients with Amelogenesis Imperfecta. INT J PROSTHODONT 2024; 0:1-18. [PMID: 38408131 DOI: 10.11607/ijp.8493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
PURPOSE The purpose of the study was to examine the long-term performance of bonded all-ceramic restorations, veneers in particular, in patients with Amelogenesis Imperfecta (AI). There are few studies of long-term outcome using a minimally invasive procedure in these patients. This aspect is essential when treating young patients. All-ceramic restorations, especially veneers, offer a more tissue-preserving treatment but rely on a successful bonding. Due to the defect enamel in AI patients, the bond strength is however lower. MATERIAL AND METHODS A retro-prospective evaluation of 40 subjects with AI (26 women, 14 men) was provided with a total of 360 bonded restorations (282 veneers, 78 crowns). The restorations were evaluated according to complications, survival- and success rate. RESULTS The patients were observed up to 25,3 years (mean 15,4 ± 4,3 years). The mean age when receiving the restorations was 18,5 (± 4,2) years. There had been 59 (16,4%) restorations with prosthetic complications of which 29 (8.1%) had been remade (6 due to esthetic reasons, all in one patient) and 30 (8.3%) recemented (60% caused by trauma). We found 11 teeth with caries and 3 with endodontic complications. The over-all survival rate was 91,9% and the over-all success rate was 83,6%. CONCLUSION Bonded all-ceramic restorations with no active retention in AI patients perform excellent. The most common complications were debonding and fractures. The treatment should be on individual indications and been preceded by a multidisciplinary approach.
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Alsterstål-Englund H, Moberg LE, Petersson J, Smedberg JI. A retrospective clinical evaluation of extensive tooth-supported fixed dental prostheses after 10 years. J Prosthet Dent 2020; 125:65-72. [PMID: 32059857 DOI: 10.1016/j.prosdent.2019.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 10/08/2019] [Accepted: 10/08/2019] [Indexed: 10/25/2022]
Abstract
STATEMENT OF PROBLEM The survival and success of tooth-supported fixed dental prostheses (FDPs) in long-term studies vary greatly, depending on the patient and the size of the FDP. Influencing factors for FDP survival or success may include advanced patient age at the time of FDP treatment, treatment severity, and use of new and cheaper FDP materials. As the patient population ages, prosthodontists will treat tooth wear in a greater number of older adults; however, recent long-term studies on such treatments are lacking. PURPOSE The purpose of this retrospective clinical study was to examine extensive, tooth-supported FDPs made at 2 specialist clinics in Sweden after 10 years and to compare the outcomes with those of previous studies. MATERIAL AND METHODS Patients rehabilitated by using FDPs of at least 5 units at 2 specialist clinics in Sweden between 2002 and 2006 were recalled after 10 years. Clinical examinations were supplemented by reviewing clinical records and existing radiographs. Statistical analysis was performed by using the Student t test, chi-squared test, Fisher exact test, and Kruskal-Wallis test (α=.05). RESULTS A total of 152 patients were recalled for clinical examination. Of these, 78 patients attended and were examined. The mean age of the examined group was 70 years (range 36-94), lower than that of those not attending (80 years; range 46-100; P<.05). The mean number of units of the 78 examined FDPs was 7.3 (range 5-12) and 8.0 (range 5-14) for those not examined. FDP configurations in terms of number of units, abutments, pontics, and post-and-cores did not differ significantly between the 2 groups (P>.05). The survival proportion of the examined 78 FDPs (all units of the original FPD) was 74.4%. The success proportion (FDPs without complications) was 52.6%. The most frequent complications were caries (14.1%), endodontic complications (11.5%), loose retainers (7.7%), root fractures (5.1%), and framework fractures (3.8%). FDPs with post-and-cores (P<.05) and cantilevers (P=.054), especially when in combination (P<.05), showed more complications than FDPs without. Chipping fractures in porcelain were found in 38% of the FDPs (7.7% of the units), with more porcelain fractures on Co-Cr frameworks than on gold and titanium alloy frameworks (P<.05). CONCLUSIONS This long-term retrospective study indicated that the prognosis for complicated and extensive FDPs in aging patients does not worsen with increased clinical complexity. New materials, treatment complexity, and older patients did not seem to markedly influence prognosis.
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Affiliation(s)
- Helena Alsterstål-Englund
- Specialist in Dental Prosthetics, Department of Prosthetic Dentistry, Folktandvården Eastman Institute, Stockholm, Sweden.
| | - Lars-Erik Moberg
- Specialist in Dental Prosthetics, Department of Prosthetic Dentistry, Folktandvården Eastman Institute, Stockholm, Sweden
| | - Jenny Petersson
- Specialist in Dental Prosthetics, Department of Prosthetic Dentistry, Folktandvården South Älvsborgs Hospital, Borås, Sweden
| | - Jan-Ivan Smedberg
- Specialist in Dental Prosthetics, Department of Prosthetic Dentistry, Folktandvården Eastman Institute, Stockholm, Sweden
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Ekblom K, Smedberg JI, Moberg LE. Clinical evaluation of fixed partial dentures made in Sweden and China. Swed Dent J 2011; 35:111-121. [PMID: 22135942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The aim of this study was to compare the quality of fixed partial dentures (FPDs) made in a Chinese dental laboratory with corresponding FPDs made in Swedish dental laboratories. Twenty-one patients were fitted with FPDs between March 2007 and December 2008. Single crowns and prostheses of up to seven units were made. All dentures, gold and CoCr alloys covered with ceramic, were produced in duplicate: one by a dental technician in China and the other by a dental technician in Sweden. The dentures were blind-tested with regard to marginal integrity, anatomic form and color, approximal and occlusal contacts, and time taken for adjustments. The composition of dentures was analyzed, and the material used, framework weight, compliance of the laboratories, and costs (material and labour) were recorded. There was no difference in the quality of marginal integrity, anatomic form, color, approximal and occlusal contacts, or in the time taken for adjustments. The bridge frameworks made in China were thinner and lighter (p<0.01) than those made in Sweden. Three FPDs from China showed elastic deformation when tested clinically and were considered too thin for clinical use. In 11 out of 14 orders from the Chinese laboratory, the gold alloy specified was not delivered and the cobalt-chromium alloy contained small amounts (0.19%) of nickel.The prostheses with gold-alloy frameworks from China cost 47% of those from Sweden (p<0.01) and those with cobalt/chromium frameworks 44% (p<0.01). In conclusion, the quality of the FPDs made in Sweden and China was comparable, with the exception of the dimension of the Chinese bridges, which in some cases was considered too weak. The gold alloy ordered from the Chinese laboratory was often not the alloy delivered and the CoCr alloy contained small amounts of nickel. FPDs from China cost less than half the price of those from Sweden.
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Affiliation(s)
- Karin Ekblom
- Clinic for Prosthetic Dentistry, Public Dental Health Service, Nyköping, Sweden.
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Aslani E, Johansson J, Moberg LE. Resin-bonded bridges by dental undergraduates: three-year follow-up. Swed Dent J 2001; 25:21-9. [PMID: 11392603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
This study was conducted to evaluate performance and longevity of resin-bonded bridges in patients treated by undergraduate dental students. A total of 62 bridges had been constructed for 53 patients by the students at the School of Dentistry, Karolinska Institute, between 1989 and 1997. After a mean observation period of 35.3 months retention had been lost in 13.6% of 59 bridges examined (4.6% per year). The debonding rate was greater in the mandible (8.3 %/year) than in the maxilla (2.7 %/year), and greatest in the mandibular anterior region (13.4%). Thirty-nine patients with 46 bridges (27 maxillary and 19 mandibular bridges), underwent more detailed clinical examination. No significant differences in bleeding and pocket depth were found between abutment teeth and controls. Bleeding was more frequent at the approximal than the lingual surfaces of the abutment teeth. A questionnaire revealed high patient satisfaction, the resin-bonded bridges meeting their expectations. The study suggests that resin-bonded bridges are an acceptable alternative to conventional bridges. Successful outcome is dependent on stringent case selection, an abutment preparation designed to establish retention form, and meticulous bonding procedures.
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Affiliation(s)
- E Aslani
- Department of Prosthodontics, Institution of Odontology, Karolinska Institute, Stockholm, Sweden
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Moberg LE, Köndell PA, Sagulin GB, Bolin A, Heimdahl A, Gynther GW. Brånemark System and ITI Dental Implant System for treatment of mandibular edentulism. A comparative randomized study: 3-year follow-up. Clin Oral Implants Res 2001; 12:450-61. [PMID: 11564104 DOI: 10.1034/j.1600-0501.2001.120504.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In a randomized prospective study, two implant systems were compared in forty consecutive patients treated for mandibular edentulism. The patients were randomly allotted for treatment by the Brånemark two-stage (submerged) system (BRS), or the ITI(R) one-stage (non-submerged) system. In all, 102 Brånemark selftapping implants and 106 ITI hollow screw implants were installed and all patients were treated with full bridges. Biological and prosthodontic parameters, complications, success rates, clinical efficacy, patient satisfaction and resource requirements were evaluated. No differences were found in plaque accumulation, bleeding or complications during the follow-up period. The BRS group showed deeper periimplant sulcus, less attached mucosa, larger bridge-mucosa distance and higher Periotest values. Prosthetic complications were not related to the configuration of the implant systems. After 3 years, the cumulative success rates were 97.9% and 96.8% for the Brånemark and ITI systems, respectively (difference not statistically significant). One implant in the BRS group had failed to osseointegrate at the time of abutment connection, and another was lost after 2 years due to progressive breakdown of bone. In the ITI group, three implants showed progressive bone loss after 1-3 years associated with periimplant infection. All 40 bridges were intact and remained stable throughout the study. There was general patient satisfaction, but about half the Brånemark patients reported difficulty in coping with the surgical procedures. Treatment time was similar for the two systems. It is concluded that both systems meet the current requirements for dental implant systems in the treatment of mandibular edentulism.
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MESH Headings
- Adaptation, Psychological
- Adult
- Aged
- Attitude to Health
- Bone Resorption/etiology
- Dental Abutments
- Dental Implantation, Endosseous/adverse effects
- Dental Implantation, Endosseous/instrumentation
- Dental Implantation, Endosseous/methods
- Dental Implantation, Endosseous/psychology
- Dental Implants/adverse effects
- Dental Implants/psychology
- Dental Plaque/etiology
- Dental Prosthesis Design
- Dental Prosthesis, Implant-Supported
- Dental Restoration Failure
- Denture, Complete, Lower
- Female
- Follow-Up Studies
- Gingival Hemorrhage/etiology
- Humans
- Jaw, Edentulous/rehabilitation
- Jaw, Edentulous/surgery
- Logistic Models
- Male
- Mandible/surgery
- Mandibular Diseases/etiology
- Middle Aged
- Osseointegration
- Patient Satisfaction
- Periodontal Attachment Loss/etiology
- Periodontal Pocket/etiology
- Prospective Studies
- Statistics as Topic
- Treatment Outcome
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Affiliation(s)
- L E Moberg
- Department of Prosthodontics, Karolinska Institute, S-141 04 Huddinge, Sweden
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Moberg LE, Köndell PA, Kullman L, Heimdahl A, Gynther GW. Evaluation of single-tooth restorations on ITI dental implants. A prospective study of 29 patients. Clin Oral Implants Res 1999; 10:45-53. [PMID: 10196789 DOI: 10.1034/j.1600-0501.1999.100106.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
From January 1992 to March 1997, a total of 30 ITI hollow cylinder implants were installed to replace lost single maxillary incisor teeth. Conical abutments with cemented all-ceramic crowns were used in 10 cases and the Octa-abutment with screw-retained metallo-ceramic crowns in 19 cases. One implant failed due to postoperative infection, and was extracted a month after installation. After a mean observation time of 3.4 years, the cumulative success rate is 96.7%. Only minor bone loss has occurred around the implants, and there have been no other complications to date. The implant system fulfills the requirements for good function and esthetics.
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Affiliation(s)
- L E Moberg
- Department of Prosthodontics, Karolinska Institute, Huddinge, Sweden
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Gynther GW, Köndell PA, Moberg LE, Heimdahl A. Dental implant installation without antibiotic prophylaxis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998; 85:509-11. [PMID: 9619664 DOI: 10.1016/s1079-2104(98)90281-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The objective of this study was to retrospectively compare the outcomes of dental implant treatment with and without antibiotic prophylaxis. Two groups of patients with edentulous or partially edentulous maxillas or mandibles (or both) were treated with dental implants. One group, consisting of 147 patients (790 implants), was given prophylaxis with oral phenoxymethylpenicillin; 1 g of antibiotic was administered 1 hour preoperatively, and 1 g was administered every 8 hours for 10 days postoperatively. The other group, consisting of 132 patients (664 implants) was not given any antibiotics preoperatively or postoperatively. There were no significant differences with respect to early and late postoperative infections or with respect to implant survival between the two groups. It appears that antibiotic prophylaxis for routine dental implant surgery offers no advantage for the patient.
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Affiliation(s)
- G W Gynther
- Department of Oral and Maxillofacial Surgery, Huddinge University Hospital and Karolinska Institute, Sweden
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Köndell PA, Nordenram A, Moberg LE, Eliasson S, Nyberg B. Reconstruction of the resorbed edentulous maxilla using autogenous rib grafts and osseointegrated implants. Clin Oral Implants Res 1996; 7:286-90. [PMID: 9151593 DOI: 10.1034/j.1600-0501.1996.070311.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
14 patients with severely resorbed edentulous maxillae underwent reconstruction by the use of autogenous rib graft on-lays and osseointegrated Brånemark System implants in a one-stage procedure. 75 implants were installed. 16 (21.3%) failed to osseointegrate at the abutment connection. After a mean observation period of 5.2 years, 55 (73.3%) of the original implants were osseointegrated. 10 supplementary implants were inserted in 3 patients. At the end of the observation periods, 2 patients had overdentures and 12 had fixed prostheses. The mean marginal bone loss was 2.13 mm (SD 0.47 mm) the 1st year after grafting, and 2.92 mm (SD 1.27 mm) at the end of the follow-up periods. Long-term follow-up did not show any persistent donor site discomfort. The results indicate that this technique is a conceivable alternative for patients with severe maxillary resorption.
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Affiliation(s)
- P A Köndell
- Department of Oral and Maxillofacial Surgery, Huddinge University Hospital, Karolinska Institute, Stockholm, Sweden
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Abstract
Three different methods of increasing the bond strength of resin to metal were tested: the original Silicoater technique, the Silicoater MD technique, and the Rocatec system. Metals used for the resin-bonded prostheses were gold, a cobalt-chromium (Co-Cr) alloy, and titanium. Silicoating increased the bond strength to sandblasted specimens. The original Silicoater technique produced the highest bond strengths, especially when used with the Co-Cr alloy and titanium. The Silicoater MD technique showed the lowest bond strengths for all of the test metals. Storage for 7 days with protective film on the silicoated surface did not affect the bond strength, as compared with specimens bonded immediately. The retention of the resin to the gold specimens (Rocatec system) decreased after thermocycling, but retention to the Co-Cr alloy and titanium was not affected. Various resin cements were tested and showed the same retention with the exception of Microfill Pontic, which gave a weaker bond. Scanning electron microscope (SEM) and energy-dispersive X-ray analysis (EDAX) of the specimens before and after the measurements gave no clear explanation of the differences in bond strengths between the test metals. However, it was concluded that silicoating of the metal surfaces contributed to the retention of the resin by chemical action, as no differences in adaptation of the resin to the metal were seen between specimens pretreated by sandblasting and those which were also silicoated.
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Affiliation(s)
- O Hansson
- Department of Prosthodontics, Karolinska Institute, Huddinge, Sweden
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Hansson O, Moberg LE. Clinical evaluation of resin-bonded prostheses. INT J PROSTHODONT 1992; 5:533-41. [PMID: 1307013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Resin-bonded prostheses were clinically evaluated following a mean period of 41 months. The abutment teeth were minimally prepared, and one groove was placed on the surface approximating the edentulous space. Retainers were treated using the Silicoater technique. Thirty-four prostheses were made for 32 patients. Four patients were lost from the study and 30 units were re-examined. Two prostheses had debonded. The results suggest that resin-bonded prostheses can be successful if meticulous attention is given to the procedures outlined.
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Affiliation(s)
- O Hansson
- Department of Prosthodontics, Karolinska Institute, Huddinge, Sweden
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Appelgren BH, Arver S, Hjelmqvist H, Moberg LE, Rundgren M. Calciuresis elicited by spontaneous rehydration in dehydrated sheep. Acta Physiol Scand 1992; 145:197-8. [PMID: 1636449 DOI: 10.1111/j.1748-1716.1992.tb09357.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- B H Appelgren
- Department of Physiology, Karolinska Institute, Stockholm, Sweden
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Moberg LE, Appelgren B, Sjöstrand NO. Low concentrations of inorganic mercury inhibit in vitro autonomic transmission in the presence of albumin. Acta Odontol Scand 1991; 49:351-9. [PMID: 1776402 DOI: 10.3109/00016359109005931] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The influence of albumin, 4.5 and 45 g/l, on the effects of Hg2+, 10(-9)-10(-3) M, on the neuromuscular transmission of the isolated guinea-pig ileum and vas deferens was investigated. Hg2+, 10(-9)-10(-6) M, transiently increased the basal tone of the ileum in Tyrode solution without albumin. Albumin, 4.5 g/l, reversed this stimulant effect but enhanced the contractile response to direct muscle stimulation. This contractile response also increased in the vas deferens. Albumin, 45 g/l, obliterated the stimulant effects of Hg2+ on the smooth muscle of the ileum but not of the vas deferens. The effects caused by higher concentrations of Hg2+, 10(-5)-10(-4) M, were only partly inhibited when albumin was present. When neurogenic contractions were elicited in the presence of albumin (45 g/l), Hg2+, 10(-9)-10(-4) M, reduced the contractions in both organs. Consequently, Hg2+ in concentrations presently considered acceptable in blood plasma (10(-9)-10(-8) M) suppressed both cholinergic and adrenergic neuromuscular transmission even in the presence of albumin.
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Affiliation(s)
- L E Moberg
- Department of Prosthodontics, Karolinska Institutet, Stockholm, Sweden
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Moberg LE, Appelgren B, Sjöstrand NO. Albumin inhibits effects of Cu2+ on autonomic postganglionic transmission of guinea-pig ileum and vas deferens. Acta Odontol Scand 1991; 49:361-6. [PMID: 1776403 DOI: 10.3109/00016359109005932] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The influence of albumin, 4.5 and 45 g/l, on the effects of Cu2+, 10(-9)-10(-3) M, on the neuromuscular transmission of the isolated guinea-pig ileum and vas deferens was investigated. Low concentrations of Cu2+, 10(-9)-10(-6) M, caused a slight and transient increase of the contractile response to direct muscle stimulation of the vas deferens. Albumin at 4.5 g/l inhibited this effect. The basal tone of the ileum increased transiently when Cu2+ was added in the presence of albumin, 4.5 g/l. A stimulant action of Cu2+, 10(-9)-10(-6) M, was seen on both organs, when contractions were induced by nerve stimulation. All these effects were inhibited by albumin, 45 g/l. Higher concentrations of Cu2+, 10(-5)-10(-4) M, increased the basal tone of the ileum and the vas deferens. In the presence of albumin, 45 g/l, this stimulating effect of Cu2+ appeared in higher concentrations. The results suggest that Cu2+ is more likely to influence the function of neuronal tissues when the concentration of protein is low.
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Affiliation(s)
- L E Moberg
- Department of Prosthodontics, Karolinska Institutet, Stockholm, Sweden
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Abstract
The effect of phosphate concentration on corrosion was compared for two types of amalgam: a conventional alloy (ANA 68) and a high-Cu admixed alloy (Dispersalloy). The test specimens were stored for 4 months in electrolytes containing 85 mM NaCl and 85 mM NaCl with 2.5, 10, or 100 mM phosphate buffer respectively. The solutions were renewed each month and analyzed for Cu, Zn, Sn, Hg, and Ag in an atomic absorption spectrophotometer. The surfaces and cross-sections of the specimens were studied in a scanning electron microscope (SEM) with an energy dispersive detector (EDAX). The corrosion products, mainly Sn-compounds, at the surface of the amalgams were less in the solutions containing high concentrations of phosphate. In cross-section subsurface corrosion of the high-Cu amalgam was observed especially in specimens immersed in the NaCl solution without phosphate. The conventional amalgam showed surface corrosion only. The decrease in release of elements with time from the conventional amalgam in all the experimental solutions might indicate passivation. For the high-Cu amalgam the release of elements increased with time, except for Cu and Sn in the solution with 100 mM phosphate, indicating that phosphate inhibits corrosion of the Cu-Sn-phases. Release of corrosion products from the high-Cu amalgam was more dependent on the presence of phosphate than the conventional amalgam.
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Affiliation(s)
- L E Moberg
- Department of Prosthodontics, Karolinska Institutet, Huddinge, Sweden
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Abstract
The effect of area ratio, chloride concentration and brushing on amalgam in contact with gold was studied by measuring the amounts of elements released in the electrolyte. A type III gold alloy was stored for 4 months in contact with a conventional amalgam, area relations 6/1 and 6/3, in an electrolyte containing 85 mM NaCl with 10 mM phosphate buffer. A specimen with area relation 6/1 was also stored in a 10 mM NaCl solution with 10 mM phosphate buffer. The solutions were renewed each month and analyzed for Cu, Zn, Sn, Hg, and Ag in an atomic absorption spectrophotometer. Cross-sections of the amalgams were studied in a scanning electron microscope. The tendency for Sn and Cu to be released from the amalgam was greater than for the other elements. The Sn-release probably mainly originated from surface corrosion and Cu-release from subsurface corrosion. A stronger galvanic influence enhanced only the release of Cu, and to a less extent Zn. The subsurface corrosion of the amalgam and increasing release of Cu was, in contrast to the other elements, largely dependent on a high chloride concentration in the electrolyte. Light brushing of the specimens had no effect on the amounts of elements released.
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Affiliation(s)
- C Johansson
- Department of Prosthodontics, Karolinska Institutet, Huddinge, Sweden
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Abstract
Successful attachment of the oral tissues to an endosseous dental implant relies in part on its chemical stability, nontoxic properties and maintenance of normal cell functions in the surrounding tissues. The aim of this study was therefore to investigate these 3 factors experimentally. The corrosion resistance of single crystal sapphire (alpha-Al2O3) implants was analysed with respect to the release of aluminium ions; no ions could be detected in the test solutions. The influence of single crystal sapphire on the behaviour of human epithelial cells and fibroblasts derived from biopsies of the oral mucosa, was studied. The cells were cultured in chemically defined or in low serum-containing media. Compared to the corresponding control cultures, no effects on cell morphology and growth characteristics were observed. Sapphire rods were inserted subcutaneously into rats and tissue responses were examined after 4, 8 and 12 weeks post-implantation. None or slight reactions were found in the tissues. The combined evaluation of these experimental approaches indicates that single crystal sapphire is a material well suited for biological implantation.
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Affiliation(s)
- K Arvidson
- Department of Prosthetic Dentistry, Faculty of Odontology, Huddinge Hospital, Karolinska Institutet
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Abstract
One conventional and two high-Cu amalgams were tested for marginal microhardness after 2 months' corrosion in an 85 mM NaCl solution. Amalgams immersed in 200 mM phosphate buffer solution were used as controls. The microhardness tests were conducted on cross-sections of the amalgams 50 microns from the surface edges. The microstructure of the amalgams was studied in SEM and the amounts of Sn, Cu, Zn, Ag, and Hg dissolved in the solutions were analyzed with an atomic absorption spectrophotometer. For the amalgams immersed in the NaCl solution the depth of corrosion after 2 months was between 50 and 400 microns. The specimens immersed in the phosphate solution showed no signs of subsurface corrosion. The marginal microhardness of all the amalgams was reduced after corrosion in the NaCl solution. The greatest microhardness in both the uncorroded and corroded states was shown in the two high-Cu amalgams. The reduction in marginal microhardness after corrosion can probably be attributed mainly to degradation of the gamma-2 phase for the conventional amalgam and to degradation of the eta' phase for the two high-Cu amalgams.
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Affiliation(s)
- A Patsurakos
- Department of Prosthodontics, Karolinska Institute, Stockholm, Sweden
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Abstract
This study investigated the occurrence of corrosion associated with the use of metallic implants to stabilize jaw fractures. Three different types of plates, Co-Cr and Ni-Cr alloys and Titanium, were connected in vivo to the mandibular bone surface of monkeys (Cercopithecus aethiops). The animals were killed after 3 and 6 months. The mucous membrane and bone tissue were analysed for concentrations of Co, Cr, Ni, Mo, Al, and Ti by atomic absorption spectrophometry and a radiochemical neutron activation technique. With the exception of Ti, higher concentrations of all the above elements were found in the tissue near the implants when compared with contralateral controls. However, no signs of corrosion, macroscopic or microscopic, were observed on the surface of the implants.
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Affiliation(s)
- L E Moberg
- Department of Prosthodontics, Karolinska Institute, Stockholm, Sweden
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Abstract
Amalgam specimens were immersed for 30 days in 1) water, 2) 0.9% NaCl in water, 3) 0.9% NaCl and 10 mM phosphate buffer in water, and 4) 0.9% NaCl, 7.7 mM phosphate, and 6.1 mM citric acid in water. The solutions were stored in stoppered glass tubes. Hg-drops were immersed in solutions 1, 2, and 3. The concentration of mercury vapor in the air above the solutions was measured once a day. After 30 days the amounts of Cu, Zn, Hg, and Ag in the solutions were analyzed by atomic absorption spectrophotometry. The results showed that 0.9% NaCl alone or in combination with the additives increased the amounts of elements released into the solutions. The concentration of Hg0 in the glass tubes increased with the amount of Hg in the solutions, with the exception of solution No. 3, from which significantly less Hg0 evaporated. The results indicate that the composition of the saliva, oral hygiene and dietary factors may be determinants of Hg0 emission from amalgams in the oral cavity.
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Affiliation(s)
- L E Moberg
- Department of Prosthodontics, Karolinska Institute, Stockholm, Sweden
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20
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Abstract
The marginal microhardness of three different types of amalgam was tested after 2 months' immersion in an aqueous solution of NaCl (85 mM) and phosphates (Na2HPO4 100 mM and NaH2PO4 100 mM). Amalgams immersed in distilled water were used as controls. The microhardness tests were conducted at a distance of 50 micron from the margins and at the bulk of each specimen. The solutions were analyzed for Sn, Cu, Zn, Ag, and Hg by means of atomic absorption spectrophotometry (AAS). A statistically significant reduction in the marginal microhardness after immersion in the test solution was found for the conventional and the high-Cu single composition amalgam but not for the high-Cu blended amalgam. SEM-examination of cross-sections of the amalgams revealed small areas of subsurface grain boundary corrosion, no deeper than 10 micron for all the amalgams. The SEM-examination of the specimens and AAS analysis of the solutions indicated that the reduction in marginal microhardness was attributed mainly to corrosion of the Cu-rich phases for the high-Cu single composition amalgam and to corrosion of the gamma 2 phase for the conventional amalgam. The phosphates reduced the corrosion of the amalgams in the presence of NaCl. It is concluded that the marginal strength of dental amalgams in a corrosive environment is largely dependent upon their corrosion resistance.
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Affiliation(s)
- A Patsurakos
- Department of Prosthodontics, Karolinska Institute, Stockholm, Sweden
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21
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Abstract
Three types of amalgam, one conventional, ANA 68, and two with high copper content, Dispersalloy (dispersed type) and ANA 2000 (single composition type), were investigated. The amalgams were immersed for periods of 7 wk at a time, up to 35 wk, in 23 ml (37 degrees C) of 0.9% NaCl aqueous solutions and in 0.9% NaCl solution buffered with NaH2PO4 (8.8 mM) and Na2HPO4 (1.2 mM). The amalgam specimens were embedded in epoxy resin. The surface area of amalgam exposed to the solutions was 0.2 cm2 for each specimen. Every 7 wk the corrosion potential was measured, the amalgam specimens lightly brushed with a soft toothbrush, and the solutions renewed. After 14-21 wk and 35 wk the currents during anodic polarization sweeps over the amalgams were recorded. The corrosion potential for the high-Cu amalgams was somewhat more positive (noble) in the phosphate buffered solution than in the non-buffered solution during the 35 wk of corrosion. The phosphate buffer reduced the reactivity of the amalgams during anodic polarization. Corrosion made the amalgams more passive during the anodic polarization. However, all the elements leached from the amalgams into the solutions throughout the entire experiment.
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Affiliation(s)
- L E Moberg
- Department of Prosthodontics, Karolinska Institute, Stockholm, Sweden
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22
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Moberg LE. [Corrosion products from dental alloys and the effects of mercury and cupric ions on a neuro-effector system]. Tandlakartidningen 1987; 79:97-100. [PMID: 3484134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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23
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Abstract
The possible physiological significance of low concentrations of Hg2+ in the guinea-pig ileum has been investigated. Responses to nerve stimulation by single electrical shocks, acetylcholine (ACh), and histamine (Hi) and the response to ACh of a depolarized preparation were examined. A stimulant effect of Hg2+, in the concentration range of 10 nM-1 microM, dominated in intestine accommodated in biological saline solution. This excitatory effect was probably mainly due to stimulation of a depolarization-coupled initiation of the contraction. The inhibitory effect of Hg2+, 10 nM-1 microM, observed in depolarized muscle was presumably due to a decreased Ca2+ availability for the contractile process. In the higher concentration range, 1-100 microM, a probably direct action on the contractile elements causing irreversible deterioration of the preparation seems to be present.
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24
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Abstract
Specimens of various types of dental casting alloys were stored in phosphate-buffered 0.9% NaCl solution for 35 weeks. Every 7 weeks the solutions were changed and analyzed with regard to elements released from the alloys. The release of Cu from type III gold alloy increased in contact with gold alloys for metallo-ceramic use in a 1:2 area relation. However, when the area relation was reversed, no difference in the amounts of elements released was observed. Crevice corrosion was initiated with one of the Co-Cr alloys in contact with type III gold alloy. The crevice corrosion increased the amounts of Co and Cr released into the solutions. The release of Ni and Cr from the Ni-Cr alloys was prominent. These alloys were very susceptible to crevice corrosion. With one of the Ni-Cr alloys the release of elements increased in contact with type III gold alloy.
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25
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Abstract
The possible biological significance of low concentrations of Cu2+ on the guinea-pig ileum has been investigated. Responses to nerve stimulation by single electrical shocks, acetylcholine (ACh), and histamine and the response to ACh of depolarized muscle were examined. In summary, Cu2+ has diverse and dose-dependent effects on the ileum. A stimulant effect dominates in intestine accommodated in physiological saline solution. The excitatory effect of the ion, in the concentration range 10 nM-1 microM, is probably due to stimulation of a depolarization-coupled initiation of the contraction. The inhibitory effect of Cu2+ (10 nm-1 microM) is presumably due to a decreased Ca2+ availability for the contractile process. In a higher concentration range (10 microM-100 microM) the stimulant action could also, in part, be related to a copper-induced release of Ca2+ from a storage site. No effect that certainly could be ascribed to a neuronal site of action could be observed. The possible effect of Cu2+, released during corrosion of dental alloys, on oral excitable tissue such as taste and pain receptors is discussed.
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26
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Abstract
Three types of amalgams, one conventional and two with a high copper content, were stored in phosphate-buffered 0.9% NaCl solution, at pH 6, for 35 weeks. Every 7 weeks the solutions were changed and analyzed with regard to Cu, Zn, Sn, Hg, and Ag. In one of the amalgam combinations, the conventional amalgam and one of the copper-rich amalgams in an area ratio of 2:1, contact between the amalgams clearly increased the amounts of Cu, Hg, and Ag released the first 14 weeks compared with when immersed in separate solutions. With the reversed area relation, Cu, Hg, and Ag decreased when they were in contact. The conventional amalgam in contact with the other copper-rich amalgam, in an area ratio of 2:1, reduced the amount of Cu but increased the Zn released. Polishing initially decreased the amounts of Cu and Zn released compared with the unpolished amalgams.
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27
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Abstract
One conventional amalgam and two amalgams with higher copper content were stored in contact with various dental casting alloys in phosphate-buffered 0.9% NaCl solution, pH 6, at 37 degrees C during 35 weeks. Every 7 weeks the solutions were changed, and the corrosion was measured by analyzing the solutions for the amount of Cu, Zn, Sn, Hg, Ag, Co, Cr, and Ni. In the first 7 weeks the amalgams immersed in contact with acrylic or Co-Cr alloys released small amounts of elements, whereas the release was larger when the amalgams were in contact with the gold alloys. During the rest of the experiment the release of elements tended towards the same level, independent of the casting alloy in contact. In general, the high copper amalgams released more corrosion products into the solutions than the conventional one. The release of corrosion products was strongly pH-dependent. Changing the solutions more often and saturating the solutions with oxygen decreased the amounts of Hg and Ag released.
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28
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Abstract
One conventional amalgam and two amalgams with a high copper content were stored in 0.9% NaCl solution buffered with phosphate to pH 6. In one experimental series the amalgams were placed in contact with a gold alloy. Every 7 weeks the solutions were changed and analyzed with regard to elements released from the amalgams. The microstructure of the specimens was studied in a scanning electron microscope before immersion and after 7 and 35 weeks in the solution. All the amalgams corroded along the grain boundaries in the gamma 1 phase. Corrosion was greatest in the gamma 2 phase of ANA 68, in the eta phase of ANA 2000 and in the reaction zone (eta + gamma 1) surrounding the Ag-Cu-eutectic particles of Dispersalloy. The microstructure of the corroded amalgams showed similarities to amalgams corroded in vivo. The change in microstructure observed in cross-sections of the corroded specimens was related to the amounts of corrosion products released into the saline solution.
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Sairenji E, Söremark R, Noguchi K, Shimizu M, Moberg LE. Uranium content in porcelain denture teeth and in porcelain powders for ceramic crowns. Acta Odontol Scand 1982; 40:333-9. [PMID: 6960633 DOI: 10.3109/00016358209024078] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Some porcelain denture teeth and porcelain powders marketed in Sweden haven been analyzed for the content of uranium. The fission track method and the delayed neutron technique were the methods used. Compared to results published previously the content of uranium was generally found to be lower in the brands analyzed. The denture teeth contained 23-186 ppm for Anatoform, 35-137 ppm for Myerson, 15-45 ppm for Candulor G and 20-53 ppm for Vivopearl. The baked and fired porcelain powders showed values of about 2.8 ppm at most, those in the form of powder about 25 ppm at most. The radiation dose to the mucosa of the upper lip was calculated and is discussed.
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