Biomedical subjects

Jan Gottlow

Publications and source records attributed to Jan Gottlow.

11 recordsLinked to original sources

PubMed2005

Periodontal wound healing following GTR therapy of dehiscence-type defects in the monkey: short-, medium- and long-term healing.

OBJECTIVE: To describe periodontal wound healing in dehiscence-type defects following guided tissue re-generation (GTR) therapy. METHODS: Ten adult Macaca fascicularis monkeys were used. Buccal dehiscence-type defects were created at the maxillary second pre-molars and second molars. After 3 months, GTR surgery was performed. The animals were euthanized at 6 weeks, 6 months and 2 years after surgery. Block biopsies were harvested, and prepared for histological analysis. RESULTS: A new attachment apparatus was structured already after 6 weeks of healing. A 10-20 microm thin layer of acellular extrinsic fibre cementum (AEFC) had formed along the instrumented root surface. At 6 months, the thickness of the supracrestal cementum was comparable with that at 6 weeks, while the thickness of the subcrestal cementum had increased to 40-60 microm. In this zone, the cementum consisted of an inner layer of AEFC attached to the circum-pulpal dentin and an outer layer of cellular mixed fibre cementum (CMFC). The numerical extrinsic fibre density was twice that at 6 weeks. At 2 years, the periodontal tissues resembled the pristine periodontium. CONCLUSION: Periodontal healing following GTR therapy of recession-type defects will result in a restitutio ad integrum, i.e. healing by re-generation. A continuous maturation process occurs over at least 2 years.

Absorbable Implants↗

PubMed2005

The human bone-oxidized titanium implant interface: A light microscopic, scanning electron microscopic, back-scatter scanning electron microscopic, and energy-dispersive x-ray study of clinically retrieved dental implants.

BACKGROUND: Surface modification of titanium implants by anodic oxidation may lead to enhanced bone integration. For instance, in vivo studies have demonstrated formation of more bone contacts in less time than for turned control implants. In addition, oxidized implants have shown a higher resistance to torque forces, indicating a strong interlock between bone and the oxide layer. However, the structure of the oxidized titanium-bone interface in high resolution is not known. PURPOSE: The aim of the study was to analyze the human bone-oxidized titanium interface at a high-resolution level. Of particular interest was the relationship between bone tissue and the pores of the surface oxide. MATERIALS AND METHODS: Twelve clinically retrieved implants with an oxidized surface (TiUnite, Nobel Biocare AB, Göteborg, Sweden) were used. Seven were regular dental implants and five were experimental mini-implants and had been subjected to immediate, early, or no loading. They were retrieved after 5 to 9 months of healing and were processed and analyzed using light microscopy, scanning electron microscopy (SEM) in normal and back-scatter (BS-SEM) modes, and energy-dispersive x-ray (EDX) analysis techniques. RESULTS: Bone formation was observed to occur from adjacent bone structures toward the implant surface, and it was evident that bone formation had occurred at the implant surface. SEM, BS-SEM, and EDX revealed that mineralized bone had grown into the pores of the surface oxide layer, including pores with small diameters (< 2 microm). CONCLUSIONS: The clinically retrieved oxidized implants showed evidence of bone growth into the pores of the surface oxide layer. The findings indicate the establishment of a strong interlock between the bone and the oxidized titanium implant, which is suggested to be beneficial for clinical performance.

Coated Materials, Biocompatible↗

PubMed2005

Periimplant soft tissue barrier at experimental one-piece mini-implants with different surface topography in humans: A light-microscopic overview and histometric analysis.

BACKGROUND: Following connection to the oral cavity, osseointegrated dental implants and surrounding tissues are exposed to microbiologic and biomechanical challenges. The establishment of a firm functional periimplant soft tissue barrier (PSTB) is considered to be important to protect the implant's interface from invasion of bacteria. The current knowledge on the histologic architecture of the PSTB is mainly based on animal experiments. PURPOSE: The aim of this study was to histologically characterize the PSTB formed in humans around experimental one-piece mini-implants with different surface topography. MATERIALS AND METHODS: Five patients received a total of 12 experimental titanium, one-piece mini-implants with an oxidized (n = 4), an acid-etched (n = 4), or a machined (n = 4) surface distal to therapeutic implants. Following transmucosal healing of 8 weeks and at abutment connection of the regular implants, the mini-implants were harvested with a layer of surrounding hard and soft tissue. The specimens were fixed and processed for histologic sectioning according to standard procedures. The most central bucco-oral section cut in the long axis was used for morphologic analyses of the PSTB. The vertical soft tissue morphology was quantified using histometric measurements. RESULTS: The overall height of the soft tissue, that is, the biologic width, was around 4 to 4.5 mm and consisted of an epithelial and a supracrestal connective tissue barrier. The junctional epithelium established the attachment to the implant surface, whereas the collagen fibers and fibroblasts of the connective tissue seal were oriented parallel to the implant. The epithelial attachment was shorter at the oxidized and acid-etched surfaces compared with the machined surfaces. Accordingly, the oxidized and acid-etched mini-implants exhibited a longer zone of connective tissue seal. CONCLUSION: The periimplant soft tissue formed at the experimental one-piece mini-implants in humans was of a character similar to that described in animal studies. The oxidized and acid-etched implants revealed less epithelial downgrowth and longer connective tissue seal than machined implants.

Acid Etching, Dental↗

PubMed2005

Immediate occlusal loading of Brånemark System TiUnite implants placed predominantly in soft bone: 4-year results of a prospective clinical study.

BACKGROUND: Immediate occlusal implant loading has been documented as a viable treatment option for various indications. However, most of the available studies reported on the short-term outcome of this treatment modality. PURPOSE: The purpose of this prospective clinical study was to document, on a long-term basis, the outcome of immediate occlusally loaded Brånemark System Mk IV TiUnite (Nobel Biocare AB, Göteborg, Sweden) implants placed to support fixed reconstructions in various regions of the jaws. MATERIALS AND METHODS: Thirty-eight patients received a total of 51 fixed prosthetic reconstructions, all of which were connected on the day of implant insertion. Twenty restorations replaced single teeth, 30 were fixed partial dentures, and 1 was a full-arch fixed lower restoration. These prostheses were supported by 102 Brånemark System Mk IV TiUnite implants (38 maxillary and 64 mandibular), the majority of which were placed in posterior regions (88%) and mainly in soft bone (76%). Resonance frequency measurements and marginal periimplant soft tissue evaluations were conducted during the course of the study. Furthermore, radiographic examinations were performed at the time of prosthesis delivery and at the 1- and 6-month and 1-, 2-, 3-, and 4-year follow-up visits. This report summarizes the results after 4 years of loading. RESULTS: Three maxillary implants were removed, although stable, in one patient at the 8-week follow-up owing to postoperative infection in the adjacent guided bone regeneration area. No implants were lost further on. This resulted in a cumulative implant success rate of 97.1% after 4 years of prosthetic loading. The mean marginal bone remodeling after 4 years of function was 1.3 +/- SD 0.9 mm. At 4 years, absence of marginal plaque and bleeding on probing was reported for 87% and 69% of the sites, respectively, thereby remaining unchanged since the 1-year follow-up. On average, the interproximal soft tissue fill increased for both mesial and distal papillae from scores of 1.4 +/- 1.1 and 1.0 +/- 1.1, respectively, at the preoperative assessment to 2.0 +/- 0.8 and 1.7 +/- 0.8, respectively, at the 4-year assessment. CONCLUSION: The applied immediate loading protocol, in combination with a slightly tapered implant design and a modified implant surface texture, was shown to be a successful treatment alternative in regions exhibiting soft bone.

Adult↗

PubMed2004

Resonance frequency analysis of implants subjected to immediate or early functional occlusal loading. Successful vs. failing implants.

OBJECTIVES: The objective of this study was to analyze the development of implant stability by repeated resonance frequency analysis (RFA) measurements during 1 year in 23 patients treated according to an immediate/early-loading protocol. The objective was also to evaluate the possible differences between failing and successful implants. MATERIAL AND METHODS: Eighty-one Brånemark System implants were placed in 23 patients for immediate/early-occlusal loading in all jaw regions. Thirty of the implants were placed in extraction sockets and 62 were subjected to GBR procedures. Apart from clinical and radiographic examinations, the patients were followed with RFA at placement, prosthesis connection and after 1-3, 6 and 12 months. Statistical analyses were carried out to study the possible differences between implants that failed during the study period and implants that remained successful. RESULTS: Nine implants failed (11.2%) during the 1 year of loading. RFA showed a distinct different pattern between the implants that remained stable and the implants that were lost. The implants that failed during the course of the study showed a significantly lower stability already after 1 month. CONCLUSION: Within the limitations of this study, it is concluded that failing implants show a continuous decrease of stability until failure. Low RFA levels after 1 and 2 months seem to indicate an increased risk for future failure. This information may be used to avoid implant failure in the future by unloading implants with decreasing degree of stability with time as diagnosed with the RFA technique.

Dental Implantation, Endosseous↗

PubMed2003

Immediate loading in the maxilla using flapless surgery, implants placed in predetermined positions, and prefabricated provisional restorations: a retrospective 3-year clinical study.

BACKGROUND: Immediate loading of dental implants shortens the treatment time and makes it possible to give the patient an esthetic appearance during the whole treatment period. PURPOSE: The aim of the present study was to evaluate an immediate-loading treatment protocol, which included flapless surgery, implants placed in predetermined positions and connected to prefabricated provisional restorations, and the 3-year clinical results. MATERIALS AND METHODS: A total of 97 Brånemark System Mk IV implants (Nobel Biocare AB, Gothenburg, Sweden) with a machined surface were inserted in the maxillas of 46 patients. A presurgical three-dimensional model of the patients' soft tissue and underlying alveolar bone anatomy was created, which allowed the clinician to place the implants in predetermined positions and connect them to prefabricated provisional restorations. A surgical template with drilling guides corresponding to each implant was used. The apical part of the master guide was equipped with a circular "mucotome," which punched out a 5 mm hole in the mucosa to eliminate the need for flap elevation. The patients received 25 fixed partial prostheses and 27 single-tooth restorations. Bone quality and quantity were assessed. Radiographic examinations were performed on the day of surgery/loading and at the 1-, 2-, and 3-year follow-up visits. RESULTS: All implant sites showed intact buccal and lingual bone walls during surgery, confirming the accuracy of the bone-mapping procedure. The prefabricated temporary restorations fitted, meaning that the implants were positioned clinically in the same way as on the cast. Nine implants in eight patients failed during the first 8 weeks of loading. This resulted in a cumulative survival rate of 91% after 3 years of prosthetic load. The survival rate of splinted implants was 94%. The number of failed implants was significantly higher in cases of single-tooth replacements and placement in soft bone sites and smokers. The failed implants were successfully replaced according to a two-stage protocol. All patients finally received the expected restoration. The marginal bone resorption was on average 1.0 mm during the first year of loading, 0.4 mm during the second year, and 0.1 mm during the third year. CONCLUSIONS: The study confirmed the feasibility of an immediate-loading treatment protocol in the maxilla, which included flapless surgery, implants and abutments placed in predetermined positions, and prefabricated provisional restorations. All failures occurred within the first 2 months of loading. The unchanged survival rate and the low average bone loss found during the following 34-month study period indicate a good long-term prognosis for the performed immediate-loading treatment.

Adult↗

PubMed2003

Immediate occlusal loading of Brånemark TiUnite implants placed predominantly in soft bone: 1-year results of a prospective clinical study.

BACKGROUND: The original Brånemark protocol for dental implant treatment was based on submerged healing prior to loading. However, immediate loading has been reported possible with high success rates for various indications, provided that good bone quality and quantity are present. In many of these studies, machined-surface implants have been used. Recently, a new surface texture has been developed, based on an oxidation processing, that aims to enhance the early bone response (Brånemark System Mk IV TiUnite , Nobel Biocare AB, Gothenburg, Sweden). It has been documented that this surface texture may help to better maintain primary implant stability during the early healing period and that secondary implant stability can be reached earlier compared with results when using a machined surface. Such a positive influence on implant stability might be an advantage when applying an immediate-loading protocol, especially in soft bone regions where a tendency toward reduced success rates has been reported. PURPOSE: The aim of this report was to present the short-term success rates of TiUnite-surfaced immediate occlusally loaded Brånemark System Mk IV implants placed in various regions of the jaws. MATERIALS AND METHODS: Thirty-eight patients received a total of 51 prosthetic reconstructions, all of which were connected on the day the implants were inserted. Of these, 20 were single-tooth restorations, 30 were fixed partial dentures, and 1 was a complete fixed lower jaw restoration. These prostheses were supported by 102 Brånemark System Mk IV TiUnite implants (38 maxillary and 64 mandibular), the majority of which were placed in posterior regions (88%) and mainly in soft bone (76%). Cutting resistance measurements were performed during implant insertion, and resonance frequency measurements were conducted during the course of the study. Furthermore, radiographic examinations were performed in connection with the delivery of the prostheses and at the 1-, 6-, and 12-month follow-up visits. This article reports on the results after 1 year of loading. RESULTS: Three maxillary implants were removed, although stable, in one patient at the 8-week follow-up because of postoperative infection in the adjacent area of guided bone regeneration (GBR). This resulted in a cumulative success rate of the implants of 97.1% after 1 year of prosthetic loading. The mean marginal bone resorption after 1 year of loading was 1.2 +/- 0.9 mm (SD). CONCLUSIONS: The applied immediate loading protocol in combination with a slightly tapered implant and a modified implant surface texture was shown to be a successful treatment alternative even in regions exhibiting soft bone.

Adult↗

PubMed2003

Immediate loading of Brånemark System TiUnite and machined-surface implants in the posterior mandible: a randomized open-ended clinical trial.

BACKGROUND: Immediate loading of osseointegrating implants shortens the treatment time and makes it possible to give the patient an esthetic appearance during the whole treatment period. A previous retrospective clinical study showed a success rate of 94.2% after 1 year of immediate loading of fixed partial constructions in the maxilla supported by machined-surface implants. The recently introduced Brånemark System TiUnite (Nobel Biocare AB, Gothenburg, Sweden) surface has been shown to better maintain primary implant stability and to help achieve secondary stability earlier compared with the machined surface. PURPOSE: The aim of the present study was to compare TiUnite and machined-surfaced Brånemark System implants when applying immediate loading of partial fixed bridges in the posterior mandible. MATERIALS AND METHODS: Forty-four patients were randomized for test and control therapy. In the test group, 22 patients received 66 Brånemark System TiUnite surface implants supporting 24 fixed partial bridges, all of which were connected on the day of implant insertion. In the control group, 22 patients received 55 Brånemark System machined-surface implants supporting 22 fixed partial bridges, which also were connected on the day of implant insertion. All constructions were two- to four-unit bridges. Bone quality and quantity were assessed. Radiographic examinations were performed on the day of surgery/loading and at the 1-year follow-up visit. RESULTS: Three TiUnite and eight machined-surface implants failed during the first 7 weeks of loading. This resulted in a cumulative success rate of 95.5% for TiUnite surface implants after 1 year of prosthetic load in the posterior mandible. The corresponding cumulative success rate for machined-surface implants was 85.5%. When using the machined-surface implants, the number of failed implants was significantly higher in smokers and in bone quality 4 sites. Such findings were not seen with the use of TiUnite implants, despite the fact that there were more smokers and more implants placed in bone quality 4 in this group. The marginal bone resorption after 1 year of loading was on average 0.9 mm (SD 0.7 mm) with the TiUnite implants and 1.0 mm (SD 0.9 mm) with the machined implants. CONCLUSIONS: The present study demonstrated a 10% higher success rate following immediate loading of partial fixed bridges in the posterior mandible supported by TiUnite surface implants compared with success with machined implants. When using the machined implants, the number of failed implants was significantly higher in smokers and in bone quality 4 sites. Such findings were not seen following the use of TiUnite implants.

Adult↗

PubMed2003

Immediate occlusal loading of single lower molars using Brånemark System Wide-Platform TiUnite implants: an interim report of a prospective open-ended clinical multicenter study.

BACKGROUND: First and second molars in the lower jaw are the most commonly missing teeth. As in other jaw regions with tooth loss, implant therapy is an attractive concept. Owing to the wide dimension of the molar teeth, wide implants seem to be a natural choice. However, wide implants in posterior mandibular regions sometimes present a problem. As an oxidized surface seems to facilitate implant integration and to result in a stronger fixation to bone, it was hypothesized that this surface would improve the performance of wide implants in posterior mandibles. As high initial stability most often is achieved in this region, it was hypothesized that the load per se is not a problem. PURPOSE: The purpose of the present study is to evaluate immediate loading of Brånemark System TiUnite Wide-Platform implants (Nobel Biocare AB, Gothenburg, Sweden) supporting single molar crowns in the lower jaw. MATERIALS AND METHODS: The study includes 44 patients treated in three separate private dental offices between March 2001 and June 2002. A total of 50 implants were placed, and all implants have passed the 6-month follow-up; 24 have been followed up for 1 year. All implants were provided with provisional crowns in centric occlusion at the time of surgery. RESULTS: No implant has been lost. Marginal bone levels were found in accordance with normal biologic width requirements. Resonance frequency analysis showed high and consistent implant stability. No biomechanical problems were found associated with the use of wide implants, and the potential physiologic problem in dense mandibular bone was eliminated. CONCLUSION: Although limited by being a short-term study, the result encourages immediate loading of single Brånemark System TiUnite Wide-Platform implants placed in the molar regions in the lower jaw.

Adult↗

PubMed2003

Histology of retrieved immediately and early loaded oxidized implants: light microscopic observations after 5 to 9 months of loading in the posterior mandible.

BACKGROUND: An increased number of publications report that one-stage surgery and immediate/early loading of dental implants may be a feasible approach for prosthetic reconstruction of the edentate patient. However, little is known about the histologic response to implants subjected to immediate/early loading in patients. PURPOSE: The aim of the present study was to histologically evaluate oxidized titanium implants subjected to loading immediately following surgery or after 2 months of healing and removed after 5 to 9 months loading. MATERIALS AND METHODS: Five patients participated in the study; each had consulted for implant treatment in the posterior mandible and subsequently volunteered to have extra implants inserted for the purpose of histologic research. Nine oxidized titanium implants (Brånemark System TiUnite , Nobel Biocare AB, Gothenburg, Sweden) were retrieved after 5 to 9 months in function. Two implants had been loaded the same day, whereas seven implants were loaded after 2 months of healing. Resonance frequency analysis was performed at retrieval on seven implants. Ground sections were prepared for histology and analyzed using light microscopic morphometry. RESULTS: Seven and 8.5 mm implants were placed, predominantly in quality 3 and 4 bone. Four implants were straight (Mk III), and five were tapered (Mk IV). All implants were clinically stable at retrieval and showed ISQ values of 65 to 79 with a mean of 71.4 +/- 4.4. Eight of the implants were able to be used for histology. A gross histologic examination showed an undisturbed healing of soft and bone tissues with no apparent differences between response to immediately and early loaded implants. Lamellar bone surrounded the implants, and remodeling was evident and more marked near the implant surface. A condensation of bone toward the implant surface was seen; this resulted in a lamina dura-like structure in trabecular bone. Thin rims of newly formed bone were often seen following the contour of the implant surface. The morphometric measurements showed a mean bone-to-implant contact value of 84.2 +/- 10.5% and a mean bone area value of 79.1 +/- 6.8%. The two immediately loaded implants showed bone-to-implant contact and bone area values of 92.9 +/- 0.1% and 84.9 +/- 0.9%, respectively. The corresponding values for the six early loaded implants were 81.4 +/- 10.6% and 77.1 +/- 6.8%, respectively. CONCLUSIONS: The present study demonstrated that oxidized implants subjected to immediate or early loading do integrate with soft and bone tissues in the posterior mandible.

Adult↗

PubMed2002

Clinical and radiographic evaluation of the 5-mm diameter regular-platform Brånemark fixture: 2- to 5-year follow-up.

PURPOSE: The purpose of this study was to report the clinical results obtained with 5-mm diameter regular-platform Brånemark implants after 2 to 5 years of follow-up. A secondary aim was to compare the clinical outcome to that of adjacently placed standard 3.75-mm fixtures in the same patients under the same operative condition and in the same prosthetic construction. MATERIALS AND METHODS: Sixty patients, with a mean age of 54 years, received a total of 97.5-mm diameter regular-platform fixtures. The majority of the implants were placed at molar sites. In 41 of the patients, 53.5-mm diameter implants were placed adjacent to 62 standard 3.75-mm diameter fixtures in the same prosthetic reconstruction. All implants were submerged for an average period of 4 to 6 months. Abutment connection was done according to standard protocol. The prosthetic treatment consisted of freestanding fixed bridges. RESULTS: The cumulative survival rate of the 5-mm diameter implants loaded for a period of 2 to 5 years was 96.9%. Only three implants failed. They were placed in type 4 bone in the posterior maxilla. Bone loss over the first year was 0.70 mm and over a 3-year period 0.81 mm. Implants placed in type 4 bone showed significantly higher bone loss. No difference in the resorption rate could be found between the maxillary and the mandibular implants or between the various implant lengths. There was no significant difference between the bone loss around the 5-mm diameter fixtures and the adjacent 3.75-mm diameter standard fixtures. CONCLUSION: The present study demonstrated a high predictability of 5-mm diameter regular-platform implants when placed in the posterior maxilla and mandible.

Adult↗