Osseointegrated dental implants are a treatment option for edentulous patients who seek greater s... more Osseointegrated dental implants are a treatment option for edentulous patients who seek greater stability and retention for their prosthesis. 1,2 Longterm implant success data have been recorded. 3,4 Guided implant placement, flapless or bone supported, was introduced more than 10 years ago, 5 and this procedure could reduce treatment time. 6 Recently, a systematic review and metaanalysis by Moraschini et al, 7 including 13 studies, reported a cumulative survival rate of 97.2%. All included studies were carried out with a mucosasupported guide and immediate loading of the implants. The cumulative survival rate and marginal bone loss of the review are comparable with those of nonguided implant surgery; however, the authors reported Dentsply Implants provided oral implants, prosthetic materials, and stereolithographic guides. M.Q. is Chair for Implant Supported Oral Rehabilitation at Dentsply Implants.
AimAlthough the complexity of the oral ecology and the ecological differences between health and ... more AimAlthough the complexity of the oral ecology and the ecological differences between health and disease are well accepted, a clear view on the dynamics in relation to disease is lacking. In this study, the prevalence and abundance of 20 key oral bacteria was assessed in health and disease and more importantly a closer look was given to the inter‐bacterial relationships.Materials and methodsA blinded microbiological database was analysed in this cross‐sectional, retrospective study. The database was constructed based on microbiological analyses of samples from 6308 patients, with gradations of periodontitis (healthy to periodontitis). Data concerning the abundance of 20 oral bacteria and probing pocket depth were provided.ResultsPorphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Eubacterium nodatum, Porphyromonas micra and Porphyromonas intermedia showed a clear increase in abundance and prevalence with increasing pocket depth. Correlation matrices illustrated that...
For several radiological examinations, a clinician can select between conventional and spiral com... more For several radiological examinations, a clinician can select between conventional and spiral computed tomography. Using both techniques, this study aimed at evaluating the difference in absorbed doses when examining a single lateral jaw segment in a human cadaver head and Rando phantom. The present study involved the placement of thermoluminescent dosimeter (TLD) chips (GR-200) in the thyroid gland, and bilaterally, in the parotid and submandibular glands and the lenses of the eyes in both a human cadaver and a Rando phantom at corresponding locations. Consecutive conventional spiral tomographic examinations were carried out in both the left upper and lower premolar area, using a Cranex TOME A multifunctional unit. Each examination consisted of 4 slices with a 2 mm slice thickness and exposure parameters of 57 kV, 56 seconds and 1.6-2.0 mA. Regarding spiral computed tomography (CT), a Somatom Plus S A scanner (Siemens, Erlangen, Germany), with a slice thickness of 1 mm with settings at 120 kV and 165 mA, was used on both phantoms and separately in the upper and lower jaw. With conventional tomography, the findings of the present study showed that the parotid and submandibular glands on the side near the X-ray tube received the highest dose, both for the cadaver head (doses ranging from 0.5 to 1.3 mGy) and the phantom (doses ranging from 0.6 to 2.6 mGy). For CT of the upper jaw, the highest doses were delivered to the parotid glands with an average absorbed dose of 9.2 and 10.6 mGy for the cadaver head and phantom, respectively. The submandibular glands received the highest doses during CT examination of the lower jaw with an average of 7.8 and 12.9 mGy for the cadaver head and phantom, respectively. It appears from the present investigation that if small edentulous regions are examined, radiation doses during conventional tomography remain much lower than during CT imaging. However, when multiple tomographic cuts are required, a spiral CT examination can replace a series of conventional examinations, especially in cases such as the rehabilitation of an edentulous upper jaw or a more complex surgery.
The aim of the present study was to assess the influence of endogenous and local factors on the o... more The aim of the present study was to assess the influence of endogenous and local factors on the occurrence of implant failure up to the abutment stage. The study comprised a group of 399 consecutive patients, which represented the total of patients who had been treated from 1995 to 1997 (with a total of 1263 Brånemark Brån-system implants) at the Department of Periodontology of the University Hospital, Catholic University Leuven. For each patient, the medical history was carefully examined. Data collection and analysis were mainly focused on endogenous factors such as hypertension, osteoporosis, hypo- or hyperthyroid function, chemotherapy, diabetes type I or II, Crohn's disease, some local factors (e.g. bone quality, reason for tooth loss) and breach of sterility during surgery. The reason for tooth loss, smoking habits, radiotherapy and other local bone factors (bone quality and quantity) were also recorded. Implant failures were recorded up to the abutment connection. The present study indicated a success rate until this stage of 97.8%. General factors such as heavy smoking, chemotherapy plus poor bone quality increased implant failure rate. Radiotherapy, limited bone volume and claustrophobia, which led to breaching the strict preoperative rules of asepsis, appeared to be the most relevant local factors for early implant failures.
The purpose of this study was to evaluate over time the marginal bone level changes around implan... more The purpose of this study was to evaluate over time the marginal bone level changes around implants installed to treat partial edentulism and to investigate the possible effect of several confounding variables. Consecutive intraoral radiographs taken with the paralleling technique were used. In all, 660 partially edentulous patients ever treated in the departments (248 males; 15-83 years of age) with 1655 implants, which were successfully integrated at abutment connection, were loaded by means of fixed partial prostheses. The observation period starting at abutment connection reached 16 years (mean 5.1). Implants were divided into three groups: 235 implants supported single-tooth crowns, 398 supported implant-tooth connected and 1022 free-standing fixed partial prostheses. Implants were placed in maxilla and mandible, both anteriorly and posteriorly. No significant difference in bone level evolution was predicted between the three groups of implants, either for posterior or for anterior sites. The estimated marginal bone loss for the first 6 months is 0.31 mm/year and after that 0.015 mm/year higher in the maxilla than in the mandible. More bone loss was predicted for the first 6 months when dehiscences existed, when a membrane or a bone graft were used, or when metal/ceramic prosthesis material was applied. Age and gender did not affect the change in bone level. The use of subsequently situated single-implant crowns to restore an edentulous space did not lead to more marginal bone loss than around splinted implants. Based on marginal bone height maintenance, the excellent prognosis of the presently used implants to support restorations in the treatment of partial edentulism was confirmed.
Glucose transport in skeletal muscle is stimulated by two distinct stimuli, insulin and exercises... more Glucose transport in skeletal muscle is stimulated by two distinct stimuli, insulin and exercises The mechanism by which exercise stimulates glucose transport is not known, although it is distinct from the insulin-mediated pathway. Recently, it has been shown that AMP-activated protein kinase (AMPK) is activated by exercise in skeletal muscle, whereas pharmacolo@cd activation of AMPK by 5-amino-4-imidazolecarboxamide riboside (AICAR) leads t o increased glucose transport. I t has been postulated, therefore, that AMPK may be the link between exercise and glucose transport. To address this, we have examined the signaling pathway involved in the stimulation of glucose uptake after activation of AMPK. Here we show that activation of AMPK by AICAR in rat muscle and mouse H-2Kh muscle cells activates glucose transport approximately twofold. AMPK in H-2Kh cells is also activated by hyperosmotic stress and the mitochondrial uncoupling agent, dinitrophenol, both of which lead t o increased glucose transport. In contrast, insulin, which activates glucose transport two-tothreefold in both r a t muscle and H-2Kh cells, has no effect on AMPK activity. A previous study has shown that AMPK phosphorylates and activates endothelid nitric oxide synthase (NOS). We show here that NOS activity in H-2K" cells is activated after stimulation of AMPK by AICAR. Treatment of H-2Kh cells o r r a t muscle with NOS inhibitors completely blocks the increase in glucose transport after activation of AMPK. In addition, an inhibitor of guanylate cyclase also blocks acti-FYont the Cellular Stress Group (L.
Objectives: The aim of this study was to compare bone behaviour around an experimental implant de... more Objectives: The aim of this study was to compare bone behaviour around an experimental implant design with a high insertion torque with the Astra-Tech r implant (control). In ten 18-month-old male minipigs, the last premolars and first molars were extracted to provide space for two implants in each quadrant. A first set of 40 implants were placed 3 months after the extraction and 40 additional implants were installed another 2 months later. The animals were sacrificed 3 months after the first implant installation so that half of the implants had healed for 1 month and the other half for 3 months. Radiological evaluation was performed at baseline, 1 month, 2 months, and 3 months after implant installation. Bone defect depth and area, bone level changes, bone-to-implant contact density, and peri-implant bone fraction were measured histomorphometrically. Results: Radiological analyses revealed a significantly higher bone loss around the experimental implants. Histomorphometric analyses confirmed significantly more bone loss, larger marginal bone defects, and a lower overall peri-implant bone fraction around the experimental implants. The experimental implant design caused significantly more peri-implant bone loss compared with the control implant. As strain gauge measurements indicate excessive marginal strains around the experimental implants, osseocompression might have played a role in the observed marginal bone loss.
Clinical Implant Dentistry and Related Research, 2012
This in vivo split-mouth randomized controlled trial compared a synthetic bone substitute with a ... more This in vivo split-mouth randomized controlled trial compared a synthetic bone substitute with a bovine bone mineral to cover bone dehiscences after implant insertion. Fourteen patients received four to six implants to support an overdenture. Two comparable dehiscences within the same patient were first covered with a layer of autogenous bone, followed by a layer of either Bio-Oss® (group 1; Geistlich Pharma AG, Wolhusen, Switzerland) or Straumann BoneCeramic® (group 2; Institut Straumann AG, Basel, Switzerland) and sealed by a resorbable membrane. The change in vertical dimension of the defect was measured at implant placement and at abutment connection (6.5 months). Clinical and radiological parameters were evaluated up to 1 year of loading. The vertical size of the defect at surgery was 6.4 ± 1.6 mm for group 1 and 6.4 ± 2.2 mm for group 2 sites, measured from the implant shoulder. After 6.5 months, the depth of the defect was reduced to 1.5 ± 1.2 mm and 1.9 ± 1.2 mm for group 1 and group 2 sites, respectively (p > 0.05). No implants failed during follow-up. Mean marginal bone loss over the SLActive surface was 0.94 mm (group 1), 0.81 mm (group 2), and 0.93 mm (group 3, no dehiscence) after 1 year of loading. Both bone substitutes behaved equally effectively.
Clinical Implant Dentistry and Related Research, 2011
Background: The use of endosseous dental implants has become common practice for the rehabilitati... more Background: The use of endosseous dental implants has become common practice for the rehabilitation of edentulous patients, and a two-implant overdenture has been recommended as the standard of care. The use of small-diameter implants may extend treatment options and reduce the necessity for bone augmentation. However, the mechanical strength of titanium is limited, so titanium alloys with greater tensile and fatigue strength may be preferable. Purpose: This randomized, controlled, double-blind, multicenter study investigated in a split-mouth model whether small-diameter implants made from Titanium-13Zirconium alloy (TiZr, Roxolid™) perform at least as well as Titanium Grade IV implants. Methods and Materials: Patients with an edentulous mandible received one TiZr and one Ti Grade IV small-diameter bone level implant (3.3 mm, SLActive®) in the interforaminal region. The site distribution was randomized and double-blinded. Outcome measures included change in radiological peri-implant bone level from surgery to 12 months post-insertion (primary), implant survival, success, soft tissue conditions, and safety (secondary). Results: Of 91 treated patients, 87 were available for the 12-month follow-up. Peri-implant bone level change (-0.3 1 0.5 mm vs-0.3 1 0.6 mm), plaque, and sulcus bleeding indices were not significantly different between TiZr and Ti Grade IV implants. Implant survival rates were 98.9 percent and 97.8 percent, success rates were 96.6 percent and 94.4 percent, respectively. Nineteen minor and no serious adverse events were related to the study devices. Conclusion: This study confirms that TiZr small-diameter bone level implants provide at least the same outcomes after 12 months as Ti Grade IV bone level implants. The improved mechanical properties of TiZr implants may extend implant therapy to more challenging clinical situations.
Clinical Implant Dentistry and Related Research, 2000
Background: The replacement of a single tooth or several teeth by means of single-implant restora... more Background: The replacement of a single tooth or several teeth by means of single-implant restorations is an increasingly used method that needs long-term validation. Purpose: The goal of this study was to evaluate the outcome of single-implant restorations by means of fixed restorations and to define the prognosis through marginal bone level estimations. Materials and Methods: From November 1986 to June 1998, 270 Brinemark implants (215 in the upper jaw) were installed in 219 patients (106 males). Both anterior and posterior sites were involved. Of the 263 single restorations, 28 were placed in private dental offices. The patients were followed until June 1999. Results: Twelve implants failed before or at abutment connection or within 6 months afterward. Only four implants failed later. The cumulative success rates were 93% for the implants and 96.5% for the restorations over a period of 11 years. The marginal bone loss during the first 6 months after abutment connection reached 0.71 mm and then dropped to 0.036 mm annually over a period of 10 years. Conclusions: Single-implant restorations (Brinemark System") are a reliable treatment with a good long-term prognosis. Failures were concentrated during the healing period and early loading phase. KEY WORDS dental implants, marginal bone loss, partid edentulism, prognosis, single-tooth restoration, success he replacement of one or several missing teeth is a T prosthetic challenge, especially in the anterior region of the mouth where esthetic demands are high. Patients are reluctant to accept removable partial dentures, which are also not well tolerated by oral tissues. Conventional fixed partial prostheses are invasive to dental tissues and present a risk of pulp injury.' Fixed restorations, especially in young patients, have to be replaced several times through life, which may compromise the integrity of the supporting tissues. Jemt first described the application of osseointegrated implants for single-tooth replacements.2 He pointed out the advantage of this approach when neighboring teeth are intact. Those teeth remain mostly intact or minimally-~ ~
Clinical Implant Dentistry and Related Research, 2001
Background: The original protocol of Brinemark to achieve predictable osseointegration for oral i... more Background: The original protocol of Brinemark to achieve predictable osseointegration for oral implants has substantially been modified. One may question whether results are influenced by those modifications, especially for the longterm prognosis. Purpose: The goal of the present study was to investigate the impact of those parameters that deviate from the original protocol as defined by P-I Brhemark. Materials and Methods: In this study, 246 patients with 263 fixed partial prostheses supported by 668 Brinemark implants were followed from 1 to 15 years (mean: 6.3 yr). Radiographs were taken at the time of abutment connection, at 3 to 6 months, at 12 months, and then every 3 years. The bone level was rated mesially and distally from the implants on a total of 2588 radiographs. Results: A positive relation between abutment length and marginal bone level was found (p > .0001). The maxilla (p = .03), porcelain (p = .007), long abutments (p = .008), and regular-sized diameter implants (p = .001) all exhibited more bone loss in the first 6 months. After 6 months, only long implants showed more bone loss (p = .03). Conclusions: Overall, the marginal bone level remained stable around Brinemark implants, never surpassing 2.2 mm, even after 15 years. Although longer implants lost more bone over time, this has to be interpreted with respect to higher resorption rates in less resorbed jaws.
Clinical Implant Dentistry and Related Research, 2003
Nrickpuirrrd: The anterior mandible is generally considered a rather safe surgical area, involvin... more Nrickpuirrrd: The anterior mandible is generally considered a rather safe surgical area, involving few risks of damage to vit<iI an,itomic structures. Nevertheless, both neurosemory disturbances and hemorrhages have been reported after implant surgery in that particular area. Pirrposcx With the increasing demand for oral implant placement, the anatomy of the anterior inandible should receive more cittention. This review will focus on the anatomic peculiarities of the anterior mandible and the related clinical implications. .Ilctlioils: The scientific evidence on the anatomic, histologic, physiologic, and clinical aspects of the neurovascularization of the anterior mandible will he reviewed. Kcsrrlts: Surgical complications may be attributed to the existence of a mandibular incisive canal with a true neurovascLi-l~r supply. Potential risks may also be related to the presence of the lingual foramen and anatomic variations, such as an mtcrior looping of the mental nerve. Co/idirsiotrs; Preoperative radiographic planning for oral iniplant placement in the anterior mandible should therefore not only consider all esthetic and functional demands but should also pay particular attention to the anatomic peculiarities of this region to avoid any neurovascular complications.
Clinical Implant Dentistry and Related Research, 2002
Background: As the use of oral implants for the treatment of partially as well as fully edentulou... more Background: As the use of oral implants for the treatment of partially as well as fully edentulous patients has increased the past two decades, more specialized radiographic techniques have become available for the preoperative planning of oral implant placement. Purpose: The goal of this article was to enable clinicians to select the appropriate imaging techniques when planning for oral implants. Materials and Methods: This article reviews the available literature about various imaging techniques and their indication for the preoperative planning of oral implants. The advantages and drawbacks of each technique are described. A dosimetric overview is given relative to different radiologic techniques used in various clinical situations. Results: For preoperative planning of implant placement, advantages and drawbacks of the available imaging techniques have been considered, which allows guidelines for image technique selection to be formulated based on the clinical situation provided, considering the diagnostic yield of each technique and the radiation doses involved. Conclusions: From the available literature, it can be stated that many clinical situations demand the use of cross-sectional imaging techniques for optimal preoperative planning of implant placement. Nevertheless, such techniques are not required in cases in which the clinical examination reveals sufficient bone width and where standard radiographic examinations, such as intraoral and panoramic radiography, reveal adequate bone height and space for implant placement.
Objectives: To evaluate the dental and periodontal condition of patients with unilateral cleft li... more Objectives: To evaluate the dental and periodontal condition of patients with unilateral cleft lip and palate (UCLP) before orthodontic treatment and evaluate whether the dental and periodontal condition of these patients during and after orthodontic treatment was jeopardized by the duration of the orthodontic and surgical treatment. Design: Seventy-five individuals with UCLP (52 males, 23 females), between ages 8 and 20 years, participated in a retrospective study during their final follow-up visit with regard to dental abnormalities, such as hypodontia, external root resorption, crown and root malformation, and supernumerary teeth. Alveolar bone height and periodontal attachment loss on the cleft side were also screened before or after bone grafting and at different stages of orthodontic treatment. Results: Hypodontia of the lateral incisor was found in more than 50% of the patients on the cleft side. Second premolars and/or lateral incisors outside the cleft area were missing in 27.2% of the patients. In 32%, malformations of the teeth near the cleft were noticed. In general, the teeth around and in the cleft of the patients showed normal septal bone heights and a healthy periodontium. Sixty of the 75 patients received a bone graft to restore the interrupted alveolar process. In 93.3% of these patients, the cleft was grafted before the eruption of the canine. The periodontium of the teeth in and around the cleft in patients with UCLP observed during and after orthodontic treatment can cope relatively well with the long orthodontic treatment and combined surgical interventions. The children, who had not yet started treatment, also showed enough bone support and no periodontal problems of the teeth besides the cleft. Early secondary bone grafting seems to give optimal periodontal results.
Osseointegrated dental implants are a treatment option for edentulous patients who seek greater s... more Osseointegrated dental implants are a treatment option for edentulous patients who seek greater stability and retention for their prosthesis. 1,2 Longterm implant success data have been recorded. 3,4 Guided implant placement, flapless or bone supported, was introduced more than 10 years ago, 5 and this procedure could reduce treatment time. 6 Recently, a systematic review and metaanalysis by Moraschini et al, 7 including 13 studies, reported a cumulative survival rate of 97.2%. All included studies were carried out with a mucosasupported guide and immediate loading of the implants. The cumulative survival rate and marginal bone loss of the review are comparable with those of nonguided implant surgery; however, the authors reported Dentsply Implants provided oral implants, prosthetic materials, and stereolithographic guides. M.Q. is Chair for Implant Supported Oral Rehabilitation at Dentsply Implants.
AimAlthough the complexity of the oral ecology and the ecological differences between health and ... more AimAlthough the complexity of the oral ecology and the ecological differences between health and disease are well accepted, a clear view on the dynamics in relation to disease is lacking. In this study, the prevalence and abundance of 20 key oral bacteria was assessed in health and disease and more importantly a closer look was given to the inter‐bacterial relationships.Materials and methodsA blinded microbiological database was analysed in this cross‐sectional, retrospective study. The database was constructed based on microbiological analyses of samples from 6308 patients, with gradations of periodontitis (healthy to periodontitis). Data concerning the abundance of 20 oral bacteria and probing pocket depth were provided.ResultsPorphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Eubacterium nodatum, Porphyromonas micra and Porphyromonas intermedia showed a clear increase in abundance and prevalence with increasing pocket depth. Correlation matrices illustrated that...
For several radiological examinations, a clinician can select between conventional and spiral com... more For several radiological examinations, a clinician can select between conventional and spiral computed tomography. Using both techniques, this study aimed at evaluating the difference in absorbed doses when examining a single lateral jaw segment in a human cadaver head and Rando phantom. The present study involved the placement of thermoluminescent dosimeter (TLD) chips (GR-200) in the thyroid gland, and bilaterally, in the parotid and submandibular glands and the lenses of the eyes in both a human cadaver and a Rando phantom at corresponding locations. Consecutive conventional spiral tomographic examinations were carried out in both the left upper and lower premolar area, using a Cranex TOME A multifunctional unit. Each examination consisted of 4 slices with a 2 mm slice thickness and exposure parameters of 57 kV, 56 seconds and 1.6-2.0 mA. Regarding spiral computed tomography (CT), a Somatom Plus S A scanner (Siemens, Erlangen, Germany), with a slice thickness of 1 mm with settings at 120 kV and 165 mA, was used on both phantoms and separately in the upper and lower jaw. With conventional tomography, the findings of the present study showed that the parotid and submandibular glands on the side near the X-ray tube received the highest dose, both for the cadaver head (doses ranging from 0.5 to 1.3 mGy) and the phantom (doses ranging from 0.6 to 2.6 mGy). For CT of the upper jaw, the highest doses were delivered to the parotid glands with an average absorbed dose of 9.2 and 10.6 mGy for the cadaver head and phantom, respectively. The submandibular glands received the highest doses during CT examination of the lower jaw with an average of 7.8 and 12.9 mGy for the cadaver head and phantom, respectively. It appears from the present investigation that if small edentulous regions are examined, radiation doses during conventional tomography remain much lower than during CT imaging. However, when multiple tomographic cuts are required, a spiral CT examination can replace a series of conventional examinations, especially in cases such as the rehabilitation of an edentulous upper jaw or a more complex surgery.
The aim of the present study was to assess the influence of endogenous and local factors on the o... more The aim of the present study was to assess the influence of endogenous and local factors on the occurrence of implant failure up to the abutment stage. The study comprised a group of 399 consecutive patients, which represented the total of patients who had been treated from 1995 to 1997 (with a total of 1263 Brånemark Brån-system implants) at the Department of Periodontology of the University Hospital, Catholic University Leuven. For each patient, the medical history was carefully examined. Data collection and analysis were mainly focused on endogenous factors such as hypertension, osteoporosis, hypo- or hyperthyroid function, chemotherapy, diabetes type I or II, Crohn&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s disease, some local factors (e.g. bone quality, reason for tooth loss) and breach of sterility during surgery. The reason for tooth loss, smoking habits, radiotherapy and other local bone factors (bone quality and quantity) were also recorded. Implant failures were recorded up to the abutment connection. The present study indicated a success rate until this stage of 97.8%. General factors such as heavy smoking, chemotherapy plus poor bone quality increased implant failure rate. Radiotherapy, limited bone volume and claustrophobia, which led to breaching the strict preoperative rules of asepsis, appeared to be the most relevant local factors for early implant failures.
The purpose of this study was to evaluate over time the marginal bone level changes around implan... more The purpose of this study was to evaluate over time the marginal bone level changes around implants installed to treat partial edentulism and to investigate the possible effect of several confounding variables. Consecutive intraoral radiographs taken with the paralleling technique were used. In all, 660 partially edentulous patients ever treated in the departments (248 males; 15-83 years of age) with 1655 implants, which were successfully integrated at abutment connection, were loaded by means of fixed partial prostheses. The observation period starting at abutment connection reached 16 years (mean 5.1). Implants were divided into three groups: 235 implants supported single-tooth crowns, 398 supported implant-tooth connected and 1022 free-standing fixed partial prostheses. Implants were placed in maxilla and mandible, both anteriorly and posteriorly. No significant difference in bone level evolution was predicted between the three groups of implants, either for posterior or for anterior sites. The estimated marginal bone loss for the first 6 months is 0.31 mm/year and after that 0.015 mm/year higher in the maxilla than in the mandible. More bone loss was predicted for the first 6 months when dehiscences existed, when a membrane or a bone graft were used, or when metal/ceramic prosthesis material was applied. Age and gender did not affect the change in bone level. The use of subsequently situated single-implant crowns to restore an edentulous space did not lead to more marginal bone loss than around splinted implants. Based on marginal bone height maintenance, the excellent prognosis of the presently used implants to support restorations in the treatment of partial edentulism was confirmed.
Glucose transport in skeletal muscle is stimulated by two distinct stimuli, insulin and exercises... more Glucose transport in skeletal muscle is stimulated by two distinct stimuli, insulin and exercises The mechanism by which exercise stimulates glucose transport is not known, although it is distinct from the insulin-mediated pathway. Recently, it has been shown that AMP-activated protein kinase (AMPK) is activated by exercise in skeletal muscle, whereas pharmacolo@cd activation of AMPK by 5-amino-4-imidazolecarboxamide riboside (AICAR) leads t o increased glucose transport. I t has been postulated, therefore, that AMPK may be the link between exercise and glucose transport. To address this, we have examined the signaling pathway involved in the stimulation of glucose uptake after activation of AMPK. Here we show that activation of AMPK by AICAR in rat muscle and mouse H-2Kh muscle cells activates glucose transport approximately twofold. AMPK in H-2Kh cells is also activated by hyperosmotic stress and the mitochondrial uncoupling agent, dinitrophenol, both of which lead t o increased glucose transport. In contrast, insulin, which activates glucose transport two-tothreefold in both r a t muscle and H-2Kh cells, has no effect on AMPK activity. A previous study has shown that AMPK phosphorylates and activates endothelid nitric oxide synthase (NOS). We show here that NOS activity in H-2K" cells is activated after stimulation of AMPK by AICAR. Treatment of H-2Kh cells o r r a t muscle with NOS inhibitors completely blocks the increase in glucose transport after activation of AMPK. In addition, an inhibitor of guanylate cyclase also blocks acti-FYont the Cellular Stress Group (L.
Objectives: The aim of this study was to compare bone behaviour around an experimental implant de... more Objectives: The aim of this study was to compare bone behaviour around an experimental implant design with a high insertion torque with the Astra-Tech r implant (control). In ten 18-month-old male minipigs, the last premolars and first molars were extracted to provide space for two implants in each quadrant. A first set of 40 implants were placed 3 months after the extraction and 40 additional implants were installed another 2 months later. The animals were sacrificed 3 months after the first implant installation so that half of the implants had healed for 1 month and the other half for 3 months. Radiological evaluation was performed at baseline, 1 month, 2 months, and 3 months after implant installation. Bone defect depth and area, bone level changes, bone-to-implant contact density, and peri-implant bone fraction were measured histomorphometrically. Results: Radiological analyses revealed a significantly higher bone loss around the experimental implants. Histomorphometric analyses confirmed significantly more bone loss, larger marginal bone defects, and a lower overall peri-implant bone fraction around the experimental implants. The experimental implant design caused significantly more peri-implant bone loss compared with the control implant. As strain gauge measurements indicate excessive marginal strains around the experimental implants, osseocompression might have played a role in the observed marginal bone loss.
Clinical Implant Dentistry and Related Research, 2012
This in vivo split-mouth randomized controlled trial compared a synthetic bone substitute with a ... more This in vivo split-mouth randomized controlled trial compared a synthetic bone substitute with a bovine bone mineral to cover bone dehiscences after implant insertion. Fourteen patients received four to six implants to support an overdenture. Two comparable dehiscences within the same patient were first covered with a layer of autogenous bone, followed by a layer of either Bio-Oss® (group 1; Geistlich Pharma AG, Wolhusen, Switzerland) or Straumann BoneCeramic® (group 2; Institut Straumann AG, Basel, Switzerland) and sealed by a resorbable membrane. The change in vertical dimension of the defect was measured at implant placement and at abutment connection (6.5 months). Clinical and radiological parameters were evaluated up to 1 year of loading. The vertical size of the defect at surgery was 6.4 ± 1.6 mm for group 1 and 6.4 ± 2.2 mm for group 2 sites, measured from the implant shoulder. After 6.5 months, the depth of the defect was reduced to 1.5 ± 1.2 mm and 1.9 ± 1.2 mm for group 1 and group 2 sites, respectively (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.05). No implants failed during follow-up. Mean marginal bone loss over the SLActive surface was 0.94 mm (group 1), 0.81 mm (group 2), and 0.93 mm (group 3, no dehiscence) after 1 year of loading. Both bone substitutes behaved equally effectively.
Clinical Implant Dentistry and Related Research, 2011
Background: The use of endosseous dental implants has become common practice for the rehabilitati... more Background: The use of endosseous dental implants has become common practice for the rehabilitation of edentulous patients, and a two-implant overdenture has been recommended as the standard of care. The use of small-diameter implants may extend treatment options and reduce the necessity for bone augmentation. However, the mechanical strength of titanium is limited, so titanium alloys with greater tensile and fatigue strength may be preferable. Purpose: This randomized, controlled, double-blind, multicenter study investigated in a split-mouth model whether small-diameter implants made from Titanium-13Zirconium alloy (TiZr, Roxolid™) perform at least as well as Titanium Grade IV implants. Methods and Materials: Patients with an edentulous mandible received one TiZr and one Ti Grade IV small-diameter bone level implant (3.3 mm, SLActive®) in the interforaminal region. The site distribution was randomized and double-blinded. Outcome measures included change in radiological peri-implant bone level from surgery to 12 months post-insertion (primary), implant survival, success, soft tissue conditions, and safety (secondary). Results: Of 91 treated patients, 87 were available for the 12-month follow-up. Peri-implant bone level change (-0.3 1 0.5 mm vs-0.3 1 0.6 mm), plaque, and sulcus bleeding indices were not significantly different between TiZr and Ti Grade IV implants. Implant survival rates were 98.9 percent and 97.8 percent, success rates were 96.6 percent and 94.4 percent, respectively. Nineteen minor and no serious adverse events were related to the study devices. Conclusion: This study confirms that TiZr small-diameter bone level implants provide at least the same outcomes after 12 months as Ti Grade IV bone level implants. The improved mechanical properties of TiZr implants may extend implant therapy to more challenging clinical situations.
Clinical Implant Dentistry and Related Research, 2000
Background: The replacement of a single tooth or several teeth by means of single-implant restora... more Background: The replacement of a single tooth or several teeth by means of single-implant restorations is an increasingly used method that needs long-term validation. Purpose: The goal of this study was to evaluate the outcome of single-implant restorations by means of fixed restorations and to define the prognosis through marginal bone level estimations. Materials and Methods: From November 1986 to June 1998, 270 Brinemark implants (215 in the upper jaw) were installed in 219 patients (106 males). Both anterior and posterior sites were involved. Of the 263 single restorations, 28 were placed in private dental offices. The patients were followed until June 1999. Results: Twelve implants failed before or at abutment connection or within 6 months afterward. Only four implants failed later. The cumulative success rates were 93% for the implants and 96.5% for the restorations over a period of 11 years. The marginal bone loss during the first 6 months after abutment connection reached 0.71 mm and then dropped to 0.036 mm annually over a period of 10 years. Conclusions: Single-implant restorations (Brinemark System") are a reliable treatment with a good long-term prognosis. Failures were concentrated during the healing period and early loading phase. KEY WORDS dental implants, marginal bone loss, partid edentulism, prognosis, single-tooth restoration, success he replacement of one or several missing teeth is a T prosthetic challenge, especially in the anterior region of the mouth where esthetic demands are high. Patients are reluctant to accept removable partial dentures, which are also not well tolerated by oral tissues. Conventional fixed partial prostheses are invasive to dental tissues and present a risk of pulp injury.' Fixed restorations, especially in young patients, have to be replaced several times through life, which may compromise the integrity of the supporting tissues. Jemt first described the application of osseointegrated implants for single-tooth replacements.2 He pointed out the advantage of this approach when neighboring teeth are intact. Those teeth remain mostly intact or minimally-~ ~
Clinical Implant Dentistry and Related Research, 2001
Background: The original protocol of Brinemark to achieve predictable osseointegration for oral i... more Background: The original protocol of Brinemark to achieve predictable osseointegration for oral implants has substantially been modified. One may question whether results are influenced by those modifications, especially for the longterm prognosis. Purpose: The goal of the present study was to investigate the impact of those parameters that deviate from the original protocol as defined by P-I Brhemark. Materials and Methods: In this study, 246 patients with 263 fixed partial prostheses supported by 668 Brinemark implants were followed from 1 to 15 years (mean: 6.3 yr). Radiographs were taken at the time of abutment connection, at 3 to 6 months, at 12 months, and then every 3 years. The bone level was rated mesially and distally from the implants on a total of 2588 radiographs. Results: A positive relation between abutment length and marginal bone level was found (p > .0001). The maxilla (p = .03), porcelain (p = .007), long abutments (p = .008), and regular-sized diameter implants (p = .001) all exhibited more bone loss in the first 6 months. After 6 months, only long implants showed more bone loss (p = .03). Conclusions: Overall, the marginal bone level remained stable around Brinemark implants, never surpassing 2.2 mm, even after 15 years. Although longer implants lost more bone over time, this has to be interpreted with respect to higher resorption rates in less resorbed jaws.
Clinical Implant Dentistry and Related Research, 2003
Nrickpuirrrd: The anterior mandible is generally considered a rather safe surgical area, involvin... more Nrickpuirrrd: The anterior mandible is generally considered a rather safe surgical area, involving few risks of damage to vit<iI an,itomic structures. Nevertheless, both neurosemory disturbances and hemorrhages have been reported after implant surgery in that particular area. Pirrposcx With the increasing demand for oral implant placement, the anatomy of the anterior inandible should receive more cittention. This review will focus on the anatomic peculiarities of the anterior mandible and the related clinical implications. .Ilctlioils: The scientific evidence on the anatomic, histologic, physiologic, and clinical aspects of the neurovascularization of the anterior mandible will he reviewed. Kcsrrlts: Surgical complications may be attributed to the existence of a mandibular incisive canal with a true neurovascLi-l~r supply. Potential risks may also be related to the presence of the lingual foramen and anatomic variations, such as an mtcrior looping of the mental nerve. Co/idirsiotrs; Preoperative radiographic planning for oral iniplant placement in the anterior mandible should therefore not only consider all esthetic and functional demands but should also pay particular attention to the anatomic peculiarities of this region to avoid any neurovascular complications.
Clinical Implant Dentistry and Related Research, 2002
Background: As the use of oral implants for the treatment of partially as well as fully edentulou... more Background: As the use of oral implants for the treatment of partially as well as fully edentulous patients has increased the past two decades, more specialized radiographic techniques have become available for the preoperative planning of oral implant placement. Purpose: The goal of this article was to enable clinicians to select the appropriate imaging techniques when planning for oral implants. Materials and Methods: This article reviews the available literature about various imaging techniques and their indication for the preoperative planning of oral implants. The advantages and drawbacks of each technique are described. A dosimetric overview is given relative to different radiologic techniques used in various clinical situations. Results: For preoperative planning of implant placement, advantages and drawbacks of the available imaging techniques have been considered, which allows guidelines for image technique selection to be formulated based on the clinical situation provided, considering the diagnostic yield of each technique and the radiation doses involved. Conclusions: From the available literature, it can be stated that many clinical situations demand the use of cross-sectional imaging techniques for optimal preoperative planning of implant placement. Nevertheless, such techniques are not required in cases in which the clinical examination reveals sufficient bone width and where standard radiographic examinations, such as intraoral and panoramic radiography, reveal adequate bone height and space for implant placement.
Objectives: To evaluate the dental and periodontal condition of patients with unilateral cleft li... more Objectives: To evaluate the dental and periodontal condition of patients with unilateral cleft lip and palate (UCLP) before orthodontic treatment and evaluate whether the dental and periodontal condition of these patients during and after orthodontic treatment was jeopardized by the duration of the orthodontic and surgical treatment. Design: Seventy-five individuals with UCLP (52 males, 23 females), between ages 8 and 20 years, participated in a retrospective study during their final follow-up visit with regard to dental abnormalities, such as hypodontia, external root resorption, crown and root malformation, and supernumerary teeth. Alveolar bone height and periodontal attachment loss on the cleft side were also screened before or after bone grafting and at different stages of orthodontic treatment. Results: Hypodontia of the lateral incisor was found in more than 50% of the patients on the cleft side. Second premolars and/or lateral incisors outside the cleft area were missing in 27.2% of the patients. In 32%, malformations of the teeth near the cleft were noticed. In general, the teeth around and in the cleft of the patients showed normal septal bone heights and a healthy periodontium. Sixty of the 75 patients received a bone graft to restore the interrupted alveolar process. In 93.3% of these patients, the cleft was grafted before the eruption of the canine. The periodontium of the teeth in and around the cleft in patients with UCLP observed during and after orthodontic treatment can cope relatively well with the long orthodontic treatment and combined surgical interventions. The children, who had not yet started treatment, also showed enough bone support and no periodontal problems of the teeth besides the cleft. Early secondary bone grafting seems to give optimal periodontal results.
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Papers by Marc Quirynen