bluuebunny/crossref_metadata_2025 huggingface dataset:
The implant neck: smooth or provided with retention elements. A biomechanical approach.
Authors: Hansson Stig
Published: March 2003

A combined three‐dimensional and axisymmetric finite element analysis was made of the effect upon the peak interfacial shear stress of providing an axially loaded mandibular dental implant with retention elements all the way up to the crest of the implant as opposed to a smooth neck. The effect of increased wall thickness of the implant and of using bi‐cortical fixation as opposed to unicortical fixation was also studied. Retention elements at the implant neck were found to bring about a major decrease in the peak interfacial shear stress. Increased wall thickness and bi‐cortical fixation also resulted in decreased peak interfacial shear stress but this effect was minor. The interpretation of this was that all these three measures increase the capacity of the implant to carry axial loads. Thus from a biomechanical viewpoint it appears to be advantageous to provide the neck of screw‐shaped implants with retention elements, for example a rough surface of suitable micro‐architecture and/or a microbhyphen;thread. It is furthermore suggested that retention elements at the implant neck will counteract marginal bone resorption in accordance with Wolff's law. This paper is a revision of: Hansson, S. (1997) Some steps to improve the capacity of dental implants to resist axial loads. In: Hansson, S., ed. Towards an optimized dental implant and implant bridge design: A bio‐mechanical approach. Thesis. Göteborg; Chalmers University of Technology.
Chemical and topographical surface analysis of five different implant abutments
Authors: Sawase Takashi , Wennerberg Ann , Hallgren Carin , Albrektsson Tomas , Baba Koumei
Published: March 2003

The surface characteristics of the dental implant abutment which penetrates through the gingival mucosa and is exposed to the oral cavity play an important role not only for the biocompatibility but also for the bacterial adhesion and stagnation. The purpose of this study was to investigate the surface characteristics of 5 commercially available implant abutments which were Brånemark (Nobel Biocare, Gothenburg, Sweden), Astra (AstraTech, Mölndal, Sweden), IMZ (Friatec, Mannheim, Germany), STERI‐OSS (Denar, CA, USA) and POI (Kyocera, Kyoto, Japan). The three dimensional imaging and analysis of the surface topography were carried out using a confocal laser scanning profilometer (TopScan 3D). The chemical composition of abutment surfaces was analyzed by Auger Electron Spectroscopy (AES). The results indicated that quite different surface features were shown in three dimensional images. These features reflected roughness parameters. Sa and Scx values of these abutments in μm were Brånemark (0.23±0.09, 7.76±0.64), Astra (0.23±0.05, 7.92±0.25), IMZ (0.18±0.03, 7.76±0.80), STERI‐OSS (0.15±0.01, 10.22±0.90) and POI (0.24±0.01, 8.08±0.77), respectively. The chemical elemental analysis showed all specimens to have thin titanium oxide layers (approximately 4 to 7 nm) except POI which is anodized titanium alloy, hence it has rather a thick oxide layer (95 to 110 nm). Some minor elemental traces (S, Si and P) were also seen on the outermost layer. The specimens which were investigated in this study varied in their topography and elemental composition. These variations were strongly due to the manufacturing processes which were milling, polishing, cleaning and sometimes oxidation methods.
The immediate replacement of teeth by dental implants using homologous bone membranes to seal the sockets: clinical and radiographic findings
Authors: Rosenquist Bo , Ahmed Maha
Published: March 2003

Placement of dental implants into fresh extraction sockets has several advantages compared to the original protocol. However, the soft‐tissue handling is often complicated and the aesthetic results less rewarding. A method to use a homologous bone membrane as the sole sealer of the extraction socket after immediate implant placement is introduced and the outcome of 34 cases is presented. In 4 cases early losses of the membranes occurred (2 of these iatrogenic damage) in all other cases the homologous membranes were covered by proliferation of the surrounding mucosa within 2–4 weeks. In 2 of the 4 cases where the membranes were lost, the implants did not integrate, in the other 2 cases the implants did integrate but the sockets did not fill completely with bone and the aesthetic results were not acceptable. In all other cases bone filling of the socket occurred, the implants were stable at 180 days after insertion (functional success rate 94.1%) and the aesthetic results were excellent. The method thus seems very promising but the healing process is delicate and the operation site highly vulnerable during the first postoperative weeks. It should also be stressed that the present study offers conclusions neither about the quality of the newly formed bone nor about the quality of osseointegration offered by this bone.
Long‐term evaluation of osseointegrated implants inserted at the time or after vertical ridge augmentation
Authors: Simion Massimo , Jovanovic Sascha Alexander , Tinti Carlo , Benfenati Stefano Parma
Published: March 2003

Abstract: The purpose of the present study was to evaluate retrospectively, after 1 to 5 years of prosthetic loading, 123 implants consecutively inserted at the time of vertical ridge augmentation in 4 clinics. At the time of the implant surgery, 3 different techniques were used: the implants were allowed to protrude 2 to 7 mm from the bone level and a titanium reinforced expanded‐polytetrafluoroethylene (e‐PTFE) membrane was positioned to protect either the blood clot (Group A, 6 patients), or an allograft (Group B, 11 patients), or an autograft (Group C, 32 patients). The annual implant evaluation was carried out according to a standard protocol utilized for long term studies with endosseous implants inserted in non‐regenerated bone. Only 1 implant failed immediately after the second stage surgery and after 1 month it was substituted with a new implant. All the remaining implants appeared clinically stable, no signs of radiolucency were present at the bone–implant interface, therefore, they could be defined successfully osseointegrated. The radiographic analysis showed stable bone crest levels with a mean bone loss of 1.35 mm for the Group A, of 1.87 mm for the Group B and of 1.71 for the Group C during the period of observation. Only 2 implants demonstrated an increased crestal bone loss of 3.5 mm and 4 mm respectively at the first year examination. On the base of these results, we can confirm previous long term studies on regenerated bone and we can conclude that vertically augmented bone with GBR techniques responds to implant placement like native, non‐regenerated bone.
Biological reactions of alveolar bone to orthodontic loading of oral implants
Authors: Melsen B. , Lang N. P.
Published: March 2003

Abstract: Enosseous oral implants have been suggested as anchorage for orthodontic appliances in cases where the existing dentition cannot provide sufficient stability. Long‐term studies of oral implants have suggested that excessive loading may contribute as an etiologic factor in the pathogenesis of failing implants. The purpose of the present study was to perform a histomorphometric analysis of tissue reactions around implants subjected to a well‐defined force system. The analysis was performed on undecalcified sections cut perpendicularly to the long axis of the implant. The degree of osseointegration, bone density at varying distances from the implant as well as the relative extent of resorption and formation of alveolar bone adjacent to the implant–bone interface were evaluated. The results were correlated with the local strain of the tissue estimated by the means of a finite element analysis. It was found that loading significantly influenced both the turnover and the density of the alveolar bone in the proximity of the implants. However, even unloaded implants tended to maintain the bone characteristics of the alveolar process. On the other hand, the degree of osseointegration appeared to be independent of the loading of the implant.
Glycosaminoglycans in peri‐implant sulcus fluid from implants placed in sinus‐inlay bone grafts
Authors: Johansson Björn , Smedberg Jan‐Ivan , Langley Martin , Embery Graham
Published: March 2003

Abstract: Glycosaminoglycans (GAG) present in peri‐implant sulcus fluid (PISF) were used as an indicator of the metabolic activity in the supporting tissues of implants placed in maxillary bone or maxillary bone and bone grafts together. The study included 16 patients who received implants (Brånemark system®) and sinus‐inlay bone grafts. In 12 of these patients, the implants were placed in either maxillary bone alone or maxillary bone and sinus‐inlay bone grafts in combination. Altogether the patients received a total of 102 implants, of which 73 implants were placed in bone grafts and 29 implants in maxillary bone alone. Samples of PISF were tested at 2–8 days and at 6 months after abutment connection. Levels of the GAG’s chondroitin‐4‐sulphate (C4S) and hyaluronan (HA) were assessed using cellulose acetate electrophoresis and densitometric scanning of Alcian blue‐stained strips against known GAG standards. The C4S was used as a bone metabolic marker, and HA was used to reflect the progress of soft tissue healing. Comparing grafted and non‐grafted regions, there was no significant difference in either C4S levels or HA levels during the first 8 days or at the 6 months period. The levels of HA from the first week collection did not differ significantly from the HA level after 6 months in either type of bone. However, the level of C4S was significantly lower after 6 months than during the first week, in both maxillary and grafted bone but consistent with a normal metabolic turnover. C4S can therefore be used as an indicator of the progressive healing of bone adjacent to implants.
Absorbed doses from spiral CT and conventional spiral tomography: a phantom vs. cadaver study
Authors: Bou Serhal C. , Jacobs R. , Gijbels F. , Quirynen M. , Van Steenberghe D. , Bosmans H. , Hermans R.
Published: March 2003

Abstract: 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® 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® 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.
Morbidity of harvesting of chin grafts: a prospective study
Authors: Nkenke E. , Schultze‐Mosgau S. , Kloss F. , Neukam F. W. , Radespiel‐Tröger Martin
Published: March 2003

Abstract: In a prospective study, 20 patients who underwent harvesting of chin grafts as outpatients, were followed up for 12 months (3 further patients with incomplete follow‐up data were excluded from the study). Preoperatively and 7 days, 1, 3, 6 and 12 months postoperatively, follow‐up data were assessed. Evaluation of the superficial sensory function of the inferior alveolar nerve was determined by the Pointed‐Blunt Test and the Two‐Point‐Discrimination Test. Sensory disturbances were objectively assessed by testing thermal sensitivity with the “Pain and Thermal Sensitivity” Test (PATH Test). In addition, evaluation of the pulp sensitivity of teeth 35–45 was carried out by cold vitality testing. One week postoperatively, 8 patients were affected by superficial sensory impairment. 8 nerve territories showed hypoaesthetic reactions and 5 showed hyperaesthetic reactions. After 12 months, two patients still suffered from hypoaesthesia of one side of the chin. There was a statistically significant sensitivity impairment of the chin for all patients comparing the preoperative data of the Two‐Point‐Discrimination Test (left/right median: 8.17/8.17 mm, interquartile range (IQR) 1.00/2.00 mm) with the first postoperative measurement (left/right median 9.00/8.33 mm, IQR 1.67/2.66 mm). Comparing the latter to the last postoperative measurement there was significant tendency for regeneration of a nerve function (left/right median 8.00/7.84 mm, IQR 0.66/2.00 mm). In the PATH Test all hypoaesthetic areas could be identified by a reduction of thermal sensitivity. After the first postoperative examination 21.6% (n=38/176) of the examined teeth had lost their pulp sensitivity. After 12 postoperative months 11.4% (n=20/176) still did not react sensitively. Many of these were canines (n=8/20). Comparing the preoperative to the first postoperative examination, there was a significant reduction of pulp sensitivity. However, statistically significant recovery until the last postoperative follow‐up could not be detected. The assessed data show that patients have to be informed extensively about disturbances of the inferior alveolar nerve function lasting longer than 12 months. Moreover, the loss of pulp sensitivity is a very frequent event which has always to be taken into account. Considering the high rate of complications with harvesting of chin grafts, more prospective trials should be done to find out whether there are other donor sites for autogenous bone which put less strain on patients.
Bone reactions adjacent to titanium implants subjected to static load of different duration. A study in the dog (III)
Authors: Gotfredsen Klaus , Gotfredsen Klaus , Berglundh Tord , Lindhe Jan
Published: March 2003

Abstract: The aim of the present experiment was to study the effect of a long‐standing lateral static load on the peri‐implant bone. Three beagle dogs were used. The mandibular premolars were extracted and 12 weeks later 3 titanium implants (ITI® Dental Implant System) were installed in each quadrant. Crowns were fitted to all implants 12 weeks after the installation procedure. The anterior and central crowns were fused and connected to the posterior crown by an expansion screw. In the right side of the mandible, the expansion screws were activated every 2 weeks during a 46‐week period. During the last 10 weeks of this period, an expansion force similar to that of the right side was applied in the left. The animals were sacrificed and block biopsies of each implant site harvested and prepared for histological analysis. Sites subjected to 10 weeks or 46 weeks of lateral load had a similar (i) distribution of bone markers (ii) proportion of bone density and (iii) degree of bone‐to‐implant contact. The proportion of fluorochromes was higher at sites subjected to 10 weeks of loading than at sites subjected to 46 weeks of loading.
Biologic Width around one‐ and two‐piece titanium implants
Authors: Hermann Joachim S. , Cochran David L. , Hermann Joachim S. , Buser Daniel , Schenk Robert K. , Schoolfield John D.
Published: March 2003

Abstract: Gingival esthetics around natural teeth is based upon a constant vertical dimension of healthy periodontal soft tissues, the Biologic Width. When placing endosseous implants, however, several factors influence periimplant soft and crestal hard tissue reactions, which are not well understood as of today. Therefore, the purpose of this study was to histometrically examine periimplant soft tissue dimensions dependent on varying locations of a rough/smooth implant border in one‐piece implants or a microgap (interface) in two‐piece implants in relation to the crest of the bone, with two‐piece implants being placed according to either a submerged or a nonsubmerged technique. Thus, 59 implants were placed in edentulous mandibular areas of five foxhounds in a side‐by‐side comparison. At the time of sacrifice, six months after implant placement, the Biologic Width dimension for one‐piece implants, with the rough/smooth border located at the bone crest level, was significantly smaller (P<0.05) compared to two‐piece implants with a microgap (interface) located at or below the crest of the bone. In addition, for one‐piece implants, the tip of the gingival margin (GM) was located significantly more coronally (P<0.005) compared to two‐piece implants. These findings, as evaluated by nondecalcified histology under unloaded conditions in the canine mandible, suggest that the gingival margin (GM) is located more coronally and Biologic Width (BW) dimensions are more similar to natural teeth around one‐piece nonsubmerged implants compared to either two‐piece nonsubmerged or two‐piece submerged implants.
Short epithetic implants for orthodontic anchorage in the paramedian region of the palate
Authors: Bernhart Thomas , Dörtbudak Orhun , Watzek Georg , Freudenthaler Josef , Bantleon Hans‐Peter
Published: March 2003

Abstract: Orthodontic movement of teeth often requires maximum anchorage, so that additional resistance must be added to teeth to avoid reaction to reciprocal forces. Thus, use of endosseous implants may be a valuable alternative for ensuring stable intraoral anchorage. This study was designed to evaluate the efficacy of short epithetic implants for orthodontic anchorage in the paramedian region of the palate. Twenty‐one patients (15 female, 6 male; mean age 25.8±9.9 yrs, min 12.7, max. 48.1) were included in this study. Following adequate preoperative planning, an implant system with reduced length, which had already been used for anchorage of epitheses, was placed in the paramedian region avoiding the anterior palatine suture. After a mean period of 4 months with unloaded healing, the implants were subjected to direct or indirect orhodontic loading. Despite varying bone quality and varying vertical bone volume in this region, adequate primary stability was achieved for all of the implants. No implant was lost during the healing period. Three out of the 21 implants placed were considered as failures. Two implants loosened shortly after the start of orthodontic loading. One of these was lost at a later stage due to peri‐implant inflammation, while the other one was left in place during the 9‐month follow‐up period because no inflammation developed and this implant is still indirectly included in the orthodontic treatment. Another implant loosening was observed after 8.5 months following direct loading with 8 N. This implant was also lost due to peri‐implant inflammation. The time‐related survival probability was 84.8% after 22.9 months. As yet, 4 implants have been removed due to completion of orthodontic treatment. The results of this study indicate that short epithetic implants are suitable to achieve maximum anchorage in the paramedian region of the hard palate in orthodontic treatment.
Particulate Bioglass® reduces the viability of bacterial biofilms formed on its surface in an in vitro model
Authors: Allan Iain , Wilson Michael , Newman Hubert
Published: March 2003

Abstract: 45S5 Bioglass® is a bioactive implant material which, in its particulate form, is used in the repair of periodontal defects. The surface reactions undergone by this material in an aqueous environment may exert an antibacterial effect that would be beneficial to periodontal surgical treatment. Biofilms of Streptococcus sanguis, an early plaque former, and mixed species biofilms from a salivary inoculum grown under conditions similar to those associated with periodontal implants, were grown on particulate Bioglass® in a constant depth film fermenter (CDFF). Control biofilms were grown on inert glass particulates. At sample times of 3, 24 and 48 hours the viability of biofilms of S. sanguis grown on Bioglass® was significantly lower than for those grown on inert glass. In the experiments with subgingivally‐modelled mixed species biofilms, the total anaerobic counts were significantly lower on Bioglass® after 24 and 48 hours, but not 96 or 168 hours, compared to inert glass. Thus, particulate Bioglass® has the potential to reduce bacterial colonisation of its surface in vivo, a feature relevant to post‐surgical periodontal wound healing.
Bone formation in Transforming Growth Factor beta‐1‐loaded titanium fiber mesh implants
Authors: Vehof Johan W.M. , Haus Marcus T.U. , De Ruijter Anja E. , Jansen John A. , Spauwen Paul H.M.
Published: March 2003

Abstract: The osteoconductive properties of porous titanium (Ti) fiber mesh with or without a calcium phosphate (Ca‐P) coating and osteoinductive properties of non‐coated Ti fiber mesh loaded with recombinant human Transforming Growth Factor beta‐1 (rhTGF‐β1) were investigated in a rabbit non‐critical size cranial defect model. Nine Ca‐P‐coated and 18 non‐coated porous titanium implants, half of them loaded with rhTGF‐β1, were bilaterally placed in the cranium of 18 New Zealand White rabbits. At 8 weeks postoperative, the rabbits were sacrificed and the skulls with the implants were retrieved. Histological analysis demonstrated that in the TGF‐β1‐loaded implants, bone had been formed throughout the implant, up to its center, whereas in the non‐loaded implants only partial ingrowth of bone was observed. Bone formation had a trabecular appearance together with bone marrow‐like tissue. No difference in ingrowth could be observed between the non‐TGF‐β1‐loaded non‐coated implants and the Ca‐P‐coated ones. All histological findings were confirmed by image analysis: 97% ingrowth was seen in the rhTGF‐β1‐loaded implants, while only 57% and 54% ingrowth was observed in the non‐loaded Ca‐P‐coated and non‐coated implants, respectively. Bone surface area and bone fill were significantly higher in the rhTGF‐β1‐loaded implants (1.37 mm2 and 36%, respectively) than in the non‐loaded implants (0.57 mm2 and 26%). No statistical difference was found for any parameter between the Ca‐P‐coated and non‐coated implants. Quadruple fluorochrome labeling showed that in the Ti and Ti‐CaP implants mainly bone guidance had occurred from the former defect edge, while in the Ti‐TGF‐β1 implants bone formation had mainly started in the center of a pore and proceeded in a centrifugal manner. Our results show that: (1) the combination of Ti‐mesh with TGF‐β1 can induce orthotopic bone formation; (2) Ti‐fiber mesh has good osteoconductive properties; (3) a thin Ca‐P coating, as applied in this study, does not seem to further enhance the bone‐conducting properties of a titanium scaffold material.
Augmentation of the rat jaw with autogeneic cortico‐cancellous bone grafts and guided tissue regeneration
Authors: Donos Nikolaos , Kostopoulos Lambros , Karring Thorkild
Published: March 2003

Abstract: The aim of the present study was to evaluate the effect of augmenting the maxillary alveolar ridge and the lateral aspect of the mandible with onlay autogeneic cortico‐cancellous bone grafts that were covered with e‐PTFE membranes. The experiment was carried out in 51 rats. In 15 rats, the edentulous maxillary jaw between the incisor and the first molar was augmented by means of an autogeneic ischiac bone graft that was fixed with a gold‐coated microimplant. In one side, the graft was covered with an e‐PTFE membrane, while the other side, which served as control, was treated without a membrane. In the other 36 rats, the lateral aspect of the mandible was augmented in both sides by means of an autogeneic ischiac bone graft that was fixed with a gold‐coated or a titanium microimplant. In one side, the augmented area was covered with an e‐PTFE membrane, while the contralateral side was treated without a membrane. Histological analysis at 60, 120 and 180 days after augmentation of the maxilla showed that, in the case of the test sites (where most of the membranes were either exposed or lost), the bone grafts presented extensive resorption and there was a lack of bone continuity between the graft and the recipient site. Similar findings were made at the non‐membrane‐treated control sides. In the case of augmentation of the mandible with membranes, the bone grafts were not resorbed, but were integrated into newly formed bone at the recipient site. In the control sides, the grafts presented varying degrees of resorption and integration into the recipient bone. It is concluded that, in comparison to bone grafting alone, onlay ischiac bone grafting combined with guided tissue regeneration eliminates the risk of bone graft resorption and ensures integration of the graft into newly formed bone at the recipient site, provided that closure of the operated area can be maintained during healing.
Biologic outcome of implant‐supported restorations in the treatment of partial edentulism
Authors: Naert Ignace , Koutsikakis George , Duyck Joke , Quirynen Marc , Jacobs Reinhilde , Van Steenberghe Daniel
Published: March 2003

Abstract: The purpose of this study was to predict the outcome of implant restorations in the treatment of partial edentulism, taking into account implant interdependency and the effect of several confounding variables. Between December 1982 and June 1998, 1956 Brånemark system® implants (1212 and 744 in the maxilla and mandible, respectively, 846 distal to first premolars) were installed in 660 patients (248 males) at the Department of Periodontology of the University Hospitals of the Catholic University of Leuven. Of the 810 restorations installed at the Department of Prosthetic Dentistry of the same hospital, 235 were single crowns, 166 were supported by implants and teeth and 409 were free‐standing fixed partial prostheses. An additional 87 restorations was placed in private dental offices and were not included. The patients were followed from implant installation until June 1999. The estimated cumulative survival rates were 91.4% for all implants and 95.8% for all restorations over a period of 16 years. Estimated cumulative survival rates from loading for implant‐tooth connected and free‐standing implants were, respectively, 93.6% and 97.2%. Neither jaw site nor implant position (anterior–posterior) had any significant effect on the outcome. Short implant length, high number of implants per patient, low number of implants per prosthesis, implants loaded by acrylic‐veneered restorations and implants combined with bone grafting present a higher risk hazard for implant failure. The idea of not splinting the implants in a fixed partial prosthesis is promising but needs replication before accepting it.
Peri‐implant alveolar bone loss with respect to bone quality after use of the osteotome technique
Authors: Strietzel Frank Peter , Nowak Marcus , Küchler Ingeborg , Friedmann Anton
Published: March 2003

Abstract: Knife‐edge configurations or non space‐maintaining defects of the alveolar ridge limit the indications for implant‐prosthetic rehabilitations. If ridge expansion is required, bone splitting and bone spreading techniques may be applied. Summers introduced a modified approach for ridge expansion by osteotome technique. The principles of this nonablative implant bed preparation technique are lateral and apical bone relocation and condensation. The peri‐implant alveolar bone loss after use of the osteotome technique was evaluated radiographically with respect to the bone quality in 22 patients with 22 implants. Differences between the alveolar crest and the implant shoulder in radiographs obtained immediately after implant insertion, after the end of unloaded healing period and after different periods of functional loading were calculated. The osteotome technique was used in bone quality classes 2 and 3, respectively, according to the Lekholm and Zarb classification. Two implants failed. Significant differences were found between the bone levels after implant insertion and at the end of the healing period as well as after functional loading (P = 0.028). The bone quality was significantly correlated (r = − 0.505; P = 0.023) with the change of the peri‐implant marginal bone height level 6 months after the implant installation. The present data indicate the importance of bone quality evaluation before application of the osteotome technique.
Comparison of three different preparations of platelet concentrates for growth factor enrichment
Authors: Appel Thorsten R. , Pötzsch Bernd , Müller Jens , Von Lindern Jens‐Jörg , Bergé Stefaan J. , Reich Rudolf H.
Published: March 2003

Abstract: The aim of the present study was to compare three different systems for preparing platelet concentrates: two commercially available bed‐side techniques (Curasan system and PCCS) and a procedure used routinely in transfusion medicine. Platelet concentrates were prepared from venous blood of 12 healthy male volunteers using the three different systems. Platelet and leucocyte counts were performed and platelet derived growth factor and transforming growth factor beta were assayed by enzyme linked immunoassay. Handling was also considered. The three systems were able to collect 19.0 ± 16.6% (laboratory system), 41.9 ± 9.7% (Curasan system) and 49.6 ± 21.0% (PCCS) of the absolute number of platelets which were originally in the venous blood volume within the platelet concentrate. Due to the amount of plasma which is left in the platelet concentrate portion, the platelet concentration could be increased between 1.4 ± 1.3 times (laboratory system), 5.0 ± 2.3 times (PCCS) and 11.7 ± 2.4 times (Curasan system) compared to the venous blood. The amount of growth factors correlated with the number of platelets within the platelet concentrates. The two systems for intraoperative use are similar in their effects on the platelets. The absolute gain of platelets seems to be the highest with the PCCS; the highest concentration of platelets per µL is gained with the Curasan system. The laboratory system may offer an alternative if an intraoperative system is not available.
Healing after standardized clinical probing of the perlimplant soft tissue seal
Authors: Etter Thomas H. , Håkanson Ingrid , Lang Niklaus P. , Trejo Pedro M. , Caffesse Raul G.
Published: March 2003

Abstract: Background/Aims: Clinical probing of the soft tissues around oral implants has become a frequently used parameter for clinical monitoring. However, the healing of the disruption of the soft tissue seal as a result of probing has not yet been studied. The purpose of this study was to evaluate the healing events in the periimplant mucosal tissues following standardized clinical probing.

Material and methods: In three foxhounds the mandibular premolars were extracted and, after 3 months of healing, TPS screw‐shaped implants (ITO Dental Implant System) were installed. A plaque control regimen was performed throughout the duration of the experiment. After 3 months of healing of the transmucosal implants, clinical implant stability and healthy periimplant mucosal tissues with mostly absence of bleeding on probing were obtained. Clinical probing of the mesial and distal implant sites was performed immediately before 1, 2, 3, 5 and 7 days prior to the sacrifice of the animals. A specially manufactured titanium cylinder with a mesial and distal groove was fixed to the implants to standardize the insertion geometry of a pressure‐sensitive probe (0.2–0.25 N, tip diameter 0.45 mm). The distances from the alveolar crest to the coronal border of the connective tissue adaptation to the implant and the length of the epithelial attachment were measured histomorphometrically in nondecalcified ground sections. The buccal and lingual aspects of the implants were used to determine the components of the biological width in unprobed control sites.

Results: The probe caused a separation between the surface of the implant and the junctional epithelium, but not within the connective tissue adaptation. In general, the probe tip was located at the most coronal level of the supracrestal connective tissue as determined histologically. By 1 day after separation of the periimplant mucosal tissue by probing, an epithelial attachment of approximately 0.5 mm in the apico‐coronal direction was observed. The length of the epithelial adaptation showed a tendency to increase over time (day 2: 1.15 mm, day 3: 1.52 mm), and was complete at day 5 (1.92 mm). At the unprobed sites the epithelial attachment showed a mean length of 1.69 mm. Inflammatory infiltrates were practically nonexistent, indicating the absence of tissue trauma or infection as a result of probing.

Conclusions: Clinical probing around osseointegrated implants does not appear to have detrimental effects on the soft tissue seal and, hence, does not seem to jeopardize the longevity of oral implants. The ‘healing of the epithelial attachment’ seems to be complete 5 days after clinical probing.
Effect of anxiety on the experience of pain in implant insertion
Authors: Eli Ilana , Schwartz‐Arad Devorah , Baht Roni , Ben‐Tuvim Hilit
Published: March 2003

Abstract: Pain is a complex experience affected by such factors as stress, anxiety and cognitions. The purpose of this study was to examine the inter‐relationship between anxiety and acute pain perception under an oral surgery procedure of implant insertion. The study population consisted of 60 dental patients (58% female, mean age 42 year), who were scheduled for implant insertion in a private clinic specializing in oral surgery. Patients were evaluated on three consecutive occasions: immediately preoperatively (T1), immediately post‐operatively (T2), and at 4 weeks post‐operative follow‐up (T3). Patients were requested to complete questionnaires concerning their anxiety on each occasion and to indicate their subjective evaluations concerning pain (on visual analogue scales). Patient anxiety and pain evaluation were highest immediately before the surgical procedure (T1) with a significant decrease immediately afterwards (T2). The best predictor of the patient's pain evaluation at each time point was their state of anxiety at that time (T1: mean square = 7844.36, F = 16.26, P < 0.001; T2: mean square = 7652.74, F = 15.86, P < 0.001; T3: mean square = 5433.04, F = 8.99, P < 0.005). Pain experienced by patients in oral surgery is best predicted by their anxiety at each time point. Proper understanding of the variables that affect pain is important as they may produce emotional responses that could influence compliance.
The calcium channel blocker used with cyclosporin has an effect on gingival overgrowth
Authors: James J. A. , Marley J. J. , Jamal S. , Campbell B. A. , Short C. D. , Johnson R. W. G. , Hull P. S. , Spratt H. , Irwin C. R. , Boomer S. , Maxwell A. P. , Linden G. J.
Published: March 2003

Background/aims:

To investigate whether the choice of calcium channel blocker, used in conjunction with cyclosporin A, affected the prevalence of gingival overgrowth.

Method: A cohort of 135 renal transplant recipients who had been medicated with cyclosporin A in combination with either nifedipine (89) or amlodipine (46) since transplant, took part in the study. The inclusion criteria were that eligible subjects had been in receipt of a kidney transplant for at least 12 months, had at least 10 teeth and had not received specialist periodontal treatment. The age, gender, current drug regimen and dosage were recorded for each participant and alginate impressions taken of both arches. The presence and severity of gingival overgrowth were scored from plaster models.

Results: A higher proportion (72%) of the amlodipine group were categorised as having gingival overgrowth compared with only 53% of the nifedipine group, χ2=4.5, p<0.05. Logistic regression analysis was used to explore the relationship between the presence or absence of gingival overgrowth (dependent variable) and age, gender, time since transplant, dose of cyclosporin A, centre in which the patient was treated, and the calcium channel blocker used (independent variables). Independent predictors of gingival overgrowth in this multivariate analysis were whether the individual was treated with amlodipine or nifedipine (p=0.01) and whether the individual was young or old (p=0.01). Within the multivariate analysis, the odds ratio for amlodipine to be associated with gingival overgrowth compared with nifedipine was 3.0 (confidence interval 1.3–6.9).

Conclusions: The prevalence of gingival overgrowth in renal transplant recipients maintained on cyclosporin A and nifedipine is lower than those treated with cyclosporin A and amlodipine.
Relationship of cigarette smoking to the subgingival microbiota
Authors: Haffajee A. D. , Socransky S. S.
Published: March 2003

Background: The relationship of cigarette smoking to the composition of the subgingival microbiota is not clear. Some studies indicated higher levels of certain species in smokers, while other studies failed to detect differences in the microbiota between subjects with different smoking histories. Thus, the purpose of the present investigation was to examine the prevalence, proportions and levels of the subgingival species in adult subjects who were current, past or never smokers.

Method: 272 adult subjects ranging in age from 20–86 years with at least 20 teeth were recruited for study. Smoking history was obtained using a questionnaire. Clinical measures were taken at 6 sites per tooth at all teeth excluding third molars at a baseline visit. Subgingival plaque samples were taken from the mesial surface of all teeth excluding third molars in each subject at baseline and assayed individually for counts of 29 subgingival species using checkerboard DNA‐DNA hybridization. Subjects were subset according to smoking history into never (n=124), past (n=98) and current smokers (n=50). Uni‐variate and multi‐variate analyses were used to seek associations between smoking category and the counts, proportions and prevalence of subgingival species.

Results: Greater differences were observed for the prevalence (% of sites colonized) of the test species in the 3 smoking groups than were observed for counts or proportions of total counts. Members of the orange and red complexes including E. nodatum, F. nucleatum ss vincentii, P. intermedia, P. micros, P. nigrescens, B. forsythus, P. gingivalis and T. denticola were significantly more prevalent in current smokers than in the other 2 groups. The difference in prevalence between smokers and non‐smokers was due to greater colonization at sites with pocket depth <4 mm. Stepwise multiple linear regression analysis indicated that combinations of the prevalence of 5 microbial species and pack years accounted for 44% of the variance for mean pocket depth (p<0.000001), while the prevalence of 3 microbial taxa along with age, pack years, current smoking and gender accounted for 31% of the variance in mean attachment level (p<0.000001). The difference in prevalence between current and never smokers of all members of the red complex and 8 of 12 members of the orange complex was significantly greater in the maxilla than in the mandible.

Conclusions: The major difference between the subgingival microbiota in subjects with different smoking history was in the prevalence of species rather than counts or proportions. The greater extent of colonization in smokers appeared to be due to greater colonization at pocket depths <4 mm. Differences in colonization patterns between current and never smokers were greater in the maxilla than in the mandible.
Change in subgingival microbial profiles in adult periodontitis subjects receiving either systemically‐administered amoxicillin or metronidazole
Authors: Feres M. , Haffajee A. D. , Allard K. , Som S. , Socransky S. S.
Published: March 2003

Aim: The current investigation evaluated changes in levels and proportions of 40 bacterial species in subgingival plaque samples during, immediately after and up to 1 year after metronidazole or amoxicillin therapy combined with SRP.

Method: After baseline clinical and microbiological monitoring, 17 adult periodontitis subjects received full mouth SRP and 14 days systemic administration of either metronidazole (250 mg, TID, n=8) or amoxicillin (500 mg, TID, n=9). Clinical measurements including % of sites with plaque, gingival redness, bleeding on probing and suppuration, pocket depth (PD) and attachment level (AL) were made at baseline, 90, 180 and 360 days. Subgingival plaque samples were taken from the mesial surface of all teeth in each subject at baseline, 90, 180 and 360 days and from 2 randomly selected posterior teeth at 3, 7, and 14 days during and after antibiotic administration. Counts of 40 subgingival species were determined using checkerboard DNA‐DNA hybridization. Significance of differences over time was determined using the Quade test and between groups using ANCOVA.

Results: Mean PD was reduced from 3.22±0.12 at baseline to 2.81±0.16 (p<0.01) at 360 days and from 3.38±0.23 mm to 2.80±0.14 mm (p<0.01) in the amoxicillin and metronidazole treated subjects respectively. Corresponding values for mean AL were 3.21±0.30 to 2.76±0.32 (p<0.05) and 3.23±0.28 mm to 2.94±0.23 mm (p<0.01). Levels and proportions of Bacteroides forsythus, Porphyromonas gingivalis and Treponema denticola were markedly reduced during antibiotic administration and were lower than baseline levels at 360 days. Counts (×105, ±SEM) of B. forsythus fell from baseline levels of 0.66±0.16 to 0.04±0.02, 0.13±0.04, 0.10±0.03 and 0.42±0.19 in the amoxicillin group at 14, 90, 180 and 360 days respectively (p<0.001). Corresponding values for metronidazole treated subjects were: 1.69±0.28 to 0.02±0.01, 0.20±0.08, 0.22±0.06 and 0.22±0.08 (p<0.001). Counts of Campylobacter species, Eubacterium nodatum, Fusobacterium nucleatum subspecies, F. periodonticum and Prevotella nigrescens were also detected at lower mean levels during and immediately after therapy, but gradually increased after withdrawal of the antibiotics. Members of the genera Actinomyces, Streptococcus and Capnocytophaga were minimally affected by metronidazole. However, amoxicillin decreased the counts and proportions of Actinomyces species during and after therapy.

Conclusions: The data suggest that metronidazole and amoxicillin are useful in rapidly lowering counts of putative periodontal pathogens, but must be accompanied by other procedures to bring about periodontal stability.
Human histology of new attachment after root coverage using subepithelial connective tissue graft
Authors: Goldstein M. , Boyan B. D. , Cochran D. L. , Schwartz Z.
Published: March 2003

Background, aims: Connective tissue grafts are used successfully in periodontal therapy for root coverage. However, reports on the histologic interface between the root surface and the grafted tissue have been few in number. This report describes a case study in which a subepithelial connective tissue graft was placed in a 27‐year‐old female on the maxillary left side.

Methods: The graft (15 mm long, 10 mm wide, 1.5 mm thick) included palatal periosteum and was placed with the periosteal side facing the exposed bone and root surfaces.

Results: 15 weeks after grafting, the teeth presented with residual recessions of 1 mm, and buccal probing depths were approximately 1 mm. 14 months post‐surgery, the 1st maxillary premolars on both sides were extracted for orthodontic therapy. Clinical parameters at the graft site remained as at 15 weeks. Histologic analysis of tooth #24 showed that the sulcular epithelium was keratinized; epithelium lining the dentin exhibited rete ridges projecting into the gingival connective tissue; and junctional epithelium extended over new cementum. New connective tissue attachment was also observed, including periodontal ligament.

Conclusion: Biological width was comparable pre‐ and post‐surgery, indicating a real gain in attachment of 3.9 mm.
Computer‐based intraoral image analysis of the clinical plaque removing capacity of 3 manual toothbrushes
Authors: Staudt Christine B. , Kinzel Sonja , Haßfeld Stefan , Stein Wolfram , Staehle Hans Jörg , Dörfer Christof E.
Published: March 2003

Background: (I) Introducing an intraoral camera system with a special positioner to allow computer‐based analysis of reproducible images on lingual tooth surfaces and (II) comparing plaque removal by three manual toothbrushes with different brushhead designs (convex, multilevel and flat trimmed) on lingual mandibular tooth surfaces.

Method: In a clinical single‐blind, crossover, 24‐h plaque‐regrowth study on 25 subjects, a computer‐based index (PPI) was used to evaluate pre‐ and postbrushing plaque on lingual surfaces of mandibular premolars and molars. Subjects brushed their teeth under standardized conditions at three visits, each time with a different, randomly assigned toothbrush.

Results: The intraoral camera system allowed a reproducible and relatively convenient access to the lingual surfaces of the mandibular teeth and provided an increase in objectivity. Overall, each brush achieved statistically significant plaque removal, however, none reached clinical relevance. The multilevel brush was superior at specific sites, but failed to show statistically significant superiority in terms of overall plaque reduction. Without regard of the toothbrush used, the right handed subjects were less efficient in removing plaque from the right side compared to the left.

Conclusions: The method is able to detect even small differences in plaque reduction. None of the different brushhead designs was able to compensate an insufficient brushing techniques.