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Biomedical subjects

H Nilson

Publications and source records attributed to H Nilson.

At least 19 recordsLinked to original sources
PubMed2005

Monitoring of implant stability in grafted bone using resonance frequency analysis. A clinical study from implant placement to 6 months of loading.

The aim of this prospective study was to compare implants placed in grafted and normal non-grafted maxilla by means of resonance frequency analysis (RFA), clinical stability and implant failure. Twenty-nine patients with severe atrophy of the edentulous maxilla were treated with autogenous bone grafts as onlay (24 patients) or as interpositional grafts in conjunction with a Le Fort I osteotomy (five patients) 6 months prior to placement of 222 implants. Ten non-grafted patients treated with 75 Brånemark implants in the edentulous maxillae served as a control group. RFA was performed at implant placement, abutment connection and after 6 months of bridge loading. Seventeen (8%) implants were lost in the grafted bone and one (1%) in normal bone. RFA revealed a similar pattern in both grafted and normal maxillae, i.e. increasing resonance frequency (RF) with time (Wilcoxon Signed Rank test for paired data). Twenty implants that were rotation mobile (low primary stability) at the time of insertion showed a significantly lower value at implant placement according to RFA (Mann-Whitney U-test, P = 0.020). The RF for the failed implants revealed a tendency towards lower values (Mann-Whitney U-test, P = 0.072), compared to the successful implants. It is concluded that implants placed in grafted bone when using a two-stage technique achieve a stability similar to that of implants placed in normal non-grafted bone.

Aged↗
PubMed2000

Immediate functional loading of Brånemark single tooth implants. An 18 months' clinical pilot follow-up study.

A clinical and radiographical study was performed to evaluate the treatment outcome of single tooth replacements with artificial crowns retained to implants installed according to a 1-stage surgical procedure and immediate loading (Experimental Group = EG) in comparison to the original 2-stage concept (Control Group = CG). The EG comprised 14 patients (= 14 implants) and the CG comprised 8 patients (= 8 implants), all with single tooth losses anterior to the molars. Beyond the non-smoking criterion the following criteria were adopted: i) the amount of bone had to allow for installation of a fixture with a minimum length of 13 mm and Ø = 3.75 mm, ii) the jaw relationship had to allow for bilateral occlusal stability, iii) the patients should be judged to be non-bruxers, and iv) the patients had to be available for the follow-up and maintenance programme. In the EG a temporary crown was connected to the implant within 24 h following fixture installation. Six months later this crown was replaced with a permanent one. In the CG the surgical and prosthetic treatment followed the standard protocol. Out of the 14 fixtures in the EG 2 were lost up to 5 months in function and were subsequently removed. All remaining 12 implants were stable at every subsequent follow-up examination. No fixture losses were recorded in the CG and all implants in this group were stable at the follow-ups. At the 6-month observation interval all the participating 20 patients were radiographically examined, an examination that was repeated at the 18-month follow-up. The analysis of the radiographs from the EG as well as from the CG disclosed that during the 12-month observation period the mean change of bone support was about 0.1 mm. Further studies, designed as controlled multicenter ones, have to be performed before the results of this pilot study can be recommended for more general use.

Adult↗
PubMed1997

Interpositional bone grafting and Le Fort I osteotomy for reconstruction of the atrophic edentulous maxilla. A two-stage technique.

This study presents the results from ten consecutive patients who, because of insufficient bone volume for conventional implant placement in the maxilla, were treated with an interpositional bone graft and Le Fort I osteotomy. The endosteal implants were placed six months after the osteotomy. A total of 60 screw-shaped titanium implants (Brånemark) were placed, of which three failed to integrate during the six-month healing period. No further implants were lost during the follow-up period, ranging from 15 to 39 months after placement of the implants. All patients received fixed bridges and all have continued to function efficiently.

Adult↗
PubMed1997

Bone grafting to the maxillary sinuses, nasal floor and anterior maxilla in the atrophic edentulous maxilla. A two-stage technique.

This study presents the results from 20 consecutive patients treated with an autogenous bone graft from the iliac crest. In ten patients the graft was placed in the maxillary sinuses and the floor of the nose (inlay group). Ten patients, in addition to the inlay graft, had a corticocancellous bone block secured with mini-screws to the anterior maxillary ridge (inlay/onlay group). Endosteal implants (Brånemark) were placed six months after surgery. A total of 136 implants were placed, of which eight failed to integrate during the six-month healing period. A further 15 implants were lost during the follow-up period. For the inlay group the average follow-up period was 22 months and for the inlay/onlay group 19 months. Donor site morbidity was significantly less when iliac bone was harvested with a trephine (inlay group) than in patients treated with our routine procedure for bone harvesting (inlay/onlay group). Surgical technique, donor site morbidity, implant survival and patient acceptance are presented.

Adult↗
PubMed1997

Mk II: the self-tapping Brånemark implant: 5-year results of a prospective 3-center study.

The 5-year result of a prospective 3-center study is presented, comprising 103 patients with 288 Mk II self-tapping and 275 standard implants of the Brånemark System. Out of 363 mandibular and 200 maxillary fixtures, one Mk II was lost of the lower jaw and 13 of each implant type failed in maxillae during the study period. Cumulative prosthesis stability was 97%. Five patients accounted for more than 85% of the fixture losses. Marginal bone resorption was similar for both implant designs. Apart from the implant failures and one patient exhibiting disturbed nerve sensation of the mental nerve, no major complications were encountered. Overall, this study revealed equal cumulative success rates for standard and Mk II implants after 5 years of observation. Mandibular implants exhibited greater success rates (100%) for both tested implant types compared to maxillary implants (87%).

Adult↗
PubMed1995

Single-tooth replacement by osseointegrated Brånemark implants. A retrospective study of 82 implants.

The aim of the study was to evaluate the outcome of single-tooth restorations on Brånemark implants performed during the period 1984-1989. The material comprised 58 consecutive patients with 82 implants. The observation period varied from 1 to 5 years. Two implants were lost, both of them before loading. The overall survival rate was 97.6%. Radiographic follow-up was performed for 72 implants after 1 year and for 51 implants after 2 years. The bone loss during the first year was on average 9.6 +/- 0.1 mm and during the second year 0.1 +/- 0.1 mm. Although the observation time for most of the patients was only 2 years, the results indicate that the outcome of single-tooth restorations may be as favorable as for implants in edentulous jaws.

Adult↗
PubMed1994

Dentacolor as veneering material for titanium. A clinical evaluation after 51-72 months.

Fifty-one patients who had been provided with 104 Dentacolor veneered titanium copings/pontics were recalled after periods varying between 51 and 72 months. Fourty-two patients with 85 units-67 crowns and 18 pontics-attended. In this retrospective study the condition of the veneering material was rated by dentists who had performed the treatment. Seven units exhibited Dentacolor fractures and one obvious discoloration of the veneering material. These eight units correspond to a failure rate of 9.4%. The corresponding failure rate after 3 years was 7.1%.

Adult↗
PubMed1990

Cross-sectional study of patients fitted with fixed partial dentures with special reference to the caries situation.

The caries situation among 30 patients with fixed partial dentures was examined 3 yr after cementation of the constructions. The fit of the crowns on the abutment teeth, the size of the interproximal areas and the relation between the crown margin and the gingival margin were registered. Risk factors for caries development, such as salivary factors, microbiologic factors, oral hygiene and diet were evaluated for each patient. During the 3-yr period 54 caries lesions occurred in 25 patients. Eleven lesions were found on abutment teeth. Two were located on the root surfaces unconnected with the crown margin (greater than 2mm from the gingival margin), three were recurrent lesions, where the crown margin was located above the gingival margin but closer than 2 mm and six were recurrent lesions where the crown margin was located under the gingival margin. No single caries risk factor seemed to be so closely correlated to the number of caries lesions developed that it could be used alone to select of patients at risk. When the sum of the assumed negative factors was used, more caries was found among the patients with three or more factors with negative values in the group as a whole. However, predicting the development of caries in an individual case with a high degree of probability seems to be complicated. Generally speaking there was no indication that caries disease development was caused by the presence of the fixed partial denture per se.

Adult↗
PubMed1990

A 2-year follow-up study of titanium crowns.

In 1986, 149 patients were provided with titanium crowns. The method used for fabrication of the titanium copings involved two principles: machine duplication of models and electric discharge machining. For the veneering of the copings, Isosit was used for the first 90% of the crowns in the series, and the Dentacolor-Silicoater technique for the last 10%. Of 205 individual crowns cemented in 1986, 167 could be examined after 2 years. The crowns were rated by four independent examiners using the CDA quality evaluation system. Bleeding Index and Margin Index were also used. The Margin Integrity score was recorded as satisfactory for all crowns examined over the period studied. A vast majority of the margins were rated as excellent. Isosit (n = 145) disclosed shortcomings including fractures and substantial deteriorations of Surface and Color and of Anatomic Form. With Dentacolor as veneering material (n = 18) the results with the factors Surface and Color and Anatomic Form were still rated satisfactory after 2 years, and no fractures of the veneering material were registered. Bleeding Index and Margin Index showed comparatively small changes after 2 years.

Acrylic Resins↗
PubMed1990

Osseointegrated implants in edentulous jaws: a 2-year longitudinal study.

Osseointegrated implants in 50 edentulous jaws were studied during a 2-year observation period. The implant survival rate was 89% in the maxillae and 97% in the mandibles. The marginal bone loss averaged 1.7 mm in the maxillae and 1.1 mm in the mandibles. Most of this bone loss occurred during the first year. The bone loss was greater in jaws with a preoperatively minor resorption of the alveolar ridge than in those with moderate or advanced resorption. The bone loss was also greater at the medially positioned implants than at those more posterior.

Adult↗
PubMed1990

Impression technique for RPDs. A comparison between two methods.

The purposes of this study were threefold, 1) to develop a method for comparing various impression techniques and materials, 2) to compare the extension of impressions with ZOE-paste and silicone, and 3) to evaluate the precision for each method. A special device was constructed in order to secure an identical position of the impression trays. The results indicated that ZOE-paste impression in a border moulded tray produced more extended impressions lingually but buccally there were no difference between the chosen materials/method. No differences in precision of the two methods could be measured.

Dental Impression Materials↗
PubMed1989

Clinical results with titanium crowns fabricated with machine duplication and spark erosion.

A new method for fabrication of metal crowns has been developed by one of the authors (M.A.). There are two principles involved: machine duplication of models and electric discharge machining. The metal used is pure unalloyed titanium, which is processed as a coping and later covered by a composite resin. In 1986, 205 separate titanium crowns were made on 149 patients. One year later 192 crowns on 137 patients could be examined. Five crowns had been replaced by new ones owing to fracture of the composite resin. In accordance with the CDA quality evaluation system the following results were obtained for the remaining 187 crowns: margin integrity, 186 excellent or satisfactory (99.5%); anatomic form, 185 excellent or satisfactory (98.9%); and surface and color, 181 excellent or satisfactory results (96.8%). The 1-year results are promising, and further follow-up studies will be made.

Acrylic Resins↗
PubMed1982

A clinical re-examination of patients treated with pinledge-crowns.

A group consisting of forty patients received a clinical and radiological re-examination, of a cross-sectional type, to examine the effects of pinledge-crowns on teeth and periodontal tissues. The mean age of the material, which consisted of patients treated at the Department of Prosthetics, University of Umeå, during the period February 1969-November 1971, was 48.6 years (18 male, 22 female). In these patients fifty-one pinledge-crowns had been inserted, in 88% of the cases on a canine tooth. In every person, the contralateral tooth served as a control tooth. The teeth were examined with regard to the frequency of failure (expressed as failure rate %/year), the presence of caries, and the periodontal status. The results showed that of the total number of pinledge-crowns (fifty-one), twelve had been removed before the time of examination. At the examination it was found that one crown had extensive caries, which required a revision of the crown, and one tooth had a non-sensitive pulp with a periapical osteitis. These fourteen (27.5%) pinledge-crowns were classified as failures. The value of the failure rate expressed as %/year was, after 8 years, 3.43 pinledge/year or 3.13, if the patient was used as a unit. Concerning the periodontal effects, the difference between teeth fitted with pinledge-crowns and control teeth was small.

Adult↗
PubMedDate not supplied

A longitudinal clinical study of Procera ceramic-veneered titanium copings.

PURPOSE: The purpose of the present paper was to study the long-term clinical results with ceramic-veneered Procera titanium copings. MATERIALS AND METHODS: A total of 44 titanium copings (fabricated for 22 patients) veneered with a low-fusing ceramic were followed for 60 to 78 months. The clinical examinations were performed by licensed specialists in prosthetic dentistry. The crowns were rated according to the California Dental Association system. In addition, Bleeding Index and Margin Index were also evaluated. RESULTS: In 3 crowns ceramic fractures necessitated their replacement. Two crowns had to be replaced because of caries. The ratings for surface and color had changed markedly, from excellent to acceptable. Regarding anatomic form, with the exception of the 3 fractured ceramic crowns, there were no obvious changes. The margin integrity, aside from the 2 crowned teeth with caries, was recorded as satisfactory (excellent or acceptable) for all other crowns; in fact, a large majority were rated excellent. Regarding Bleeding Index, there were no differences between crowned teeth and control teeth. Changes in Margin Index showed that the gingiva of the crowned teeth had retracted. CONCLUSION: Of the various clinical factors evaluated, only surface and color-related to the low-fusing ceramic used for veneering-showed any obvious change during the follow-up period. Otherwise the veneered titanium copings had, in general, performed well.

Adult↗
PubMedDate not supplied

An intraindividual clinical comparison of 2 metal-ceramic systems.

PURPOSE: It has been questioned whether the surface and color of the ceramic and the metal-ceramic bond strength of a titanium-ceramic system are comparable to those of a conventional noble alloy-ceramic system. It was therefore the aim of this study to carry out an intraindividual clinical comparison between crowns fabricated according to the Procera system (titanium copings veneered with a low-fusing ceramic) and noble-alloy copings veneered with a medium-fusing ceramic. MATERIALS AND METHODS: Twenty-one crown pairs were fabricated for eighteen patients; three of the patients were each provided with two crown pairs. After 2 years nineteen crown pairs in sixteen patients could be compared. Clinical examinations were performed by two calibrated dentists who are long experienced in prosthetic dentistry. The crowns were rated according to the California Dental Association system. In addition, Bleeding Index and Margin Index were evaluated. RESULTS: After 2 years the quality of surface and color of the ceramic material seemed to have deteriorated more in titanium-ceramic crowns than in conventional metal-ceramic crowns, although the difference was not statistically significant. Regarding anatomic form, margin integrity, Bleeding Index, and Margin Index the differences between the two crown systems were small. CONCLUSION: The low-fusing ceramics have been subject to improvements during the last few years. Their bond strength to titanium seems to be comparable to that of conventional metal-ceramic systems. However, in the long run one problem may be the surface and color stability of low-fusing ceramics. To make extended long-term comparisons between the two metal-ceramic systems possible the present patient material will be followed for a longer period than the current 2 years.

Adult↗