bluuebunny/crossref_metadata_2025 huggingface dataset:
Person perception in the heat of conflict: Negative trait attributions affect procedural preferences and account for situational and cultural differences
Authors: Morris Michael W. , Leung Kwok , Iyengar Sheena S.
Published: July 2004

Disputes by their nature involve contentious behavior. If one attributes such behavior to underlying personality traits, these attributions can be quite damning. The current research investigated negative trait attributions and their impact on dispute resolution decisions. We hypothesized that judging one's opponent to be low in agreeableness and high in emotionality (e.g. stubborn and volatile) shifts one’s preference towards more formal procedures – formal in the sense that a third party judge controls the process and outcome. Drawing on the attribution literature, we hypothesized that two antecedents of these judgments (and consequent preferences) are the perceiver's level of prior information and the perceiver's cultural proclivity to explaining behavior in terms of personal dispositions. Results of an experiment measuring reactions to a hypothetical dispute found that prior information and culture (USA vs Hong Kong) increased trait attributions and preferences for formal procedures. Additionally, expectancy measures showed interaction effects suggesting that disputants dynamically construct expectancies in light of their personality impressions.
Reward allocation decisions of Chinese managers: Influence of employee categorization and allocation context
Authors: Hu Hsiu‐Hua , Hsu Wei‐Ling , Cheng Bor‐Shiuan
Published: July 2004

The purpose of the present study was to investigate the relationships between employee categorization criteria and Chinese managers’ allocation behaviors. Using a vignette approach and a four‐factor within‐subjects design, the effects of relationship (guanxi), loyalty, and competence, as well as their interactions with allocation context (private vs public) were examined. Results showed that subordinates who had a close relationship with the allocator, high loyalty, or high competence were rewarded more. Significant two‐way interaction effects indicated that relationship, loyalty and competence interactively affected Chinese managers’ reward allocation decisions. In addition, the moderating effects of allocation context on these three criteria were also significant. Limitations of the study and suggestions for further research were discussed.
Prolegomena to any Future History of Analytic Philosophy
Authors: Preston Aaron
Published: July 2004

Abstract: The careful historical and metaphilosophical attention recently bestowed upon analytic philosophy has revealed that traditional ways of defining it are inadequate. In the face of this inadequacy, contemporary authors have proposed new definitions that detach analytic philosophy from its turn of the twentieth century origins. I argue that this contemporary trend in defining analytic philosophy is misguided, and that it diminishes the likelihood of our coming to an accurate historical and metaphilosophical understanding of it. This is especially unsatisfactory since such understanding is essential to finding an adequate remedy for the widely perceived ills of contemporary analytic philosophy. I suggest that a more fruitful approach to developing such understanding might begin with treating the unity of analytic philosophy as illusory.
From Daily Life to Philosophy
Authors: Bransen Jan
Published: July 2004

Abstract: This article argues that the little everyday things of life often provide excellent entries into the intellectual problems of academic philosophy. This is illustrated with an analysis of four small stories taken from daily life in which people are in agony because they do not know what to do. It is argued that the crucial question in these stories is a philosophical question—not a closed request for empirical or formal information but an open question about how best to conceive of human experience. A discussion follows of the merits and shortcomings of transcendentalism as an attempt by philosophers to make progress. It is argued that reformulating questions is what philosophers can do to contribute to people's comfort in life. This is illustrated with an argument showing that in the small stories discussed the question of what to do should be reformulated as the question of who to be.
Biomechanical Comparison of Cortical Radial Graft versus Ulnar Transposition Graft Limb‐Sparing Techniques for the Distal Radial Site in Dogs
Authors: Pooya Hooman A. , Séguin Bernard , Mason David R. , Walsh Peter J. , Taylor Kenneth T. , Kass Philip H. , Stover Susan M.
Published: July 2004

Objective—To compare the biomechanical properties of radial graft (RG) versus ulnar transposition graft (UTG) limb‐sparing techniques in the dog.

Study design—Cadaveric study.

Animals—Six pairs of normal canine thoracic limbs.

Methods—In each pair of limbs, 1 limb was subjected to the RG technique and the other to the UTG technique. Limbs were tested in axial loading until failure. Modes of failure and biomechanical properties were compared between the 2 groups. Percent coverage of the metacarpal bone by the plate was retrospectively compared between the limbs that failed by fracture of the metacarpal bones and those that did not.

Results—RG limbs had significantly greater stiffness, yield load, maximum load, maximum energy, and post‐yield energy. All UTG limbs failed by cranial bending of the plate. Half of the RG limbs failed by caudal bending of the plate and half by fracture of the third metacarpal bone at the distal end of the plate. Limbs with <80% plate coverage of the metacarpal bone were significantly more likely to fail by metacarpal fracture.

Conclusions—The RG technique was biomechanically superior to the UTG technique under the conditions studied. At least 80% plate coverage of the metacarpal bone should be achieved.

Clinical Relevance—Exercise restriction and coaptation bandages should be considered for patients undergoing the UTG technique to minimize potential biomechanical complications.
Minimally Invasive Patent Ductus Arteriosus Occlusion in 5 Dogs
Authors: Borenstein Nicolas , Behr Luc , Chetboul Valérie , Tessier Dominique , Nicole Audrey , Jacquet Julien , Carlos Carolina , Retortillo Jose , Fayolle Pascal , Pouchelon Jean Louis , Daniel Pierre , Laborde François
Published: July 2004

Objective—To report a technique for minimally invasive occlusion of patent ductus arteriosus (PDA) and outcome in 5 dogs.

Study Design—Clinical cases.

Animals—Five, 4–6‐month‐old, dogs with PDA.

Materials and Methods—Titanium ligating clips were used for PDA closure in all dogs. Three dogs had video‐enhanced mini‐thoracotomy PDA occlusion. Two other dogs had thoracoscopic PDA occlusion using a custom‐designed thoracoscopy clip applicator.

Results—Thoracoscopic PDA occlusion was successful in both dogs in which it was attempted. Complete PDA closure was achieved in 4 dogs. Three months after surgery, the largest dog had residual ductal flow that hemodynamically was insignificant.

Conclusions—Although technically demanding, minimally invasive PDA occlusion is a safe and reliable technique in dogs. Preoperative measurement of the diameter of the PDA is crucial to determine if complete closure with metal clips can be achieved.

Clinical Relevance—Minimally invasive PDA occlusion should be considered as an alternative to occlusion via conventional thoracotomy.
Evaluation of Surgical Repair of Humeral Condylar Fractures Using Self‐Compressing Orthofix Pins in 23 Dogs
Authors: Guille April E. , Lewis Daniel D. , Anderson Timothy P. , Beaver Daniel P. , Carrera‐Justiz Sheila C. , Thompson Margaret S. , Wheeler Jason L.
Published: July 2004

Objective— To report short‐ and long‐term clinical and radiographic outcomes in dogs with humeral condylar fractures repaired using self‐compressing Orthofix pins.

Study Design— Retrospective evaluation with solicited long‐term clinical and radiographic evaluations.

Animals— Twenty‐three dogs with humeral condylar fractures.

Methods— Medical records and radiographs were reviewed. Owners were asked to return dogs for long‐term clinical and radiographic evaluation.

Results— Dogs were aged 1.5–26 months (mean±SD, 5.8±5.0 months) with 20 dogs weighing <5 kg (mean, 3.6±2.8 kg). Of 21 dogs with immediate post‐operative radiographs, 10 had anatomic reduction with the rest having either a step and/or gap at the articular surface. Kirschner wire migration and implant loosening were the most common post‐operative complications. All fractures with adequate follow‐up radiographic evaluations achieved union. Twelve of 13 dogs returned for long‐term evaluation (mean, 19.0±18.5 months) were either sound (10 dogs) or had subtle, weight‐bearing lameness (2). Fourteen dogs had radiographs ≥75 days after surgery (mean, 18.7±18.3 months), 8 dogs (57%) had no radiographic evidence of osteoarthritis (OA; mean OA score, 0.8; median 0), and all dogs had good or excellent limb function.

Conclusions— Self‐compressing Orthofix pins are suitable implants for the stabilization of humeral condylar fractures in small breed dogs. Implants were convenient and simple to use and complications were easily resolved. Dogs consistently had good long‐term clinical and radiographic outcomes with no or minimal lameness and OA.

Clinical Relevance— Self‐compressing Orthofix pins should be considered for the repair of humeral condylar fractures in small breed dogs.
Effects of Static Fixation and Dynamization after Interlocking Femoral Nailing Locked with an External Fixator: An Experimental Study in Dogs
Authors: Durall Ignacio , Falcón Carmelo , Díaz‐Bertrana Ma Carmen , Franch Jorge
Published: July 2004

Objective—To determine bone healing at 20 weeks, after either static fixation (SG) or after dynamization (DG) at 4 weeks in osteotomized canine femurs repaired with an interlocking nail (ILN) secured with a type I external skeletal fixator (ESF).

Study Design—Experimental study.

Animals—Ten adult beagle dogs.

Methods—After mid‐diaphyseal femoral osteotomy, femurs in 10 dogs were repaired with an ILN secured with 4 (2 proximal, 2 distal) threaded custom pins (TP; 2.7‐mm‐diameter cortical screw with a 2‐mm shaft attached to the screw head) to which 2 parallel connecting bars were attached in a type I ESF configuration. In 5 dogs, dynamization was performed at 4 weeks by removing the connecting bars and 2 distal screws. Limb function, range of motion of the stifle joint (ROMSJ), radiographic evidence of bone healing, and complications were studied for 20 weeks.

Results—Full limb function was achieved between 8 and 10 weeks in SG dogs, but a decreased ROMSJ was observed from 5 to 8 weeks. In DG dogs, full limb function occurred between 5 and 6 weeks except in 1 dog, and ROMSJ was considered normal in all dogs. Bone healing was not affected by dynamization. Average healing time for SG was 12.8 weeks, and for DG it was 13.6 weeks. Periosteal reaction at TP insertion points, osteolysis around the thread and head of TPs were observed in both groups. A windshield–wiper effect was observed at the tip of 1 ILN.

Conclusion—ILN locked with a type I ESF can be used for fixation of mid‐shaft femoral fractures. Dynamization at 4 weeks did not affect bone healing but did prevent stifle ankylosis and promoted earlier limb function.

Clinical Relevance—ILN locked with a type I ESF is seemingly a feasible method for repair of mid‐shaft femoral fractures and may decrease risk of nail failure.
Factors Associated with Mortality and Morbidity in Small Intestinal Volvulus in Horses
Authors: Stephen Jennifer O. , Corley Kevin T.T. , Johnston Janet K. , Pfeiffer Dirk
Published: July 2004

Objective— To determine historical, physical, and clinical factors that may affect morbidity and mortality in horses with small intestinal volvulus unrelated to other causes (e.g., incarceration, lipoma, etc.).

Study Design— Retrospective study.

Animals— Client‐owned horses (115), aged 1 month to 21 years.

Methods— Data were obtained from medical records, identified by computer search and manual review. Continuous variables were compared between affected and non‐affected horses with Mann–Whitney U‐tests and non‐continuous variables with Fisher's exact test (2 × 2 tables) or χ2‐tests (larger tables). Stepwise logistic regression analysis was used to develop a multivariable model of the risk factors, taking account of confounding and interaction.

Results— Eighty percent of horses recovered from surgery survived to hospital discharge. Neither age, breed, nor sex was related to mortality. Survivors had a significantly lower heart rate, shorter capillary refill time, and better mucous membrane color. Variables associated with worsening cardiovascular status, increased hemoconcentration, and exudation of cells and protein into peritoneal fluid were significantly associated with non‐survival. After recovery from surgery, the most serious complication was colic, which was significantly associated with non‐survival (P=.028) as was a second celiotomy (P<.01). Both of these complications were associated with a jejunocecostomy during the first surgery.

Conclusions— Significant differences in the clinical and clinicopathologic signs were identified between survivors and non‐survivors.

Clinical Relevance— These findings can be used to make a scientific assessment of prognosis in the pre‐operative, operative, and post‐operative management of horses with small intestinal volvulus.
A Modified Ventral Fixation for Surgical Management of Atlantoaxial Subluxation in 19 Dogs
Authors: Platt Simon R. , Chambers Jonathon N. , Cross Alan
Published: July 2004

Objective— To describe a modified ventral stabilization technique for surgical management of atlantoaxial subluxation in dogs and to evaluate the outcome.

Study Design— Retrospective clinical study.

Sample Population— Nineteen client‐owned dogs.

Methods— Medical records of 19 dogs with a radiographic diagnosis of atlantoaxial subluxation surgically managed by a modified ventral fixation technique (cortical screws, Kirschner wires, polymethylmethacrylate) were reviewed. Data on pre‐ and post‐operative neurologic status, surgical technique, and complications were retrieved. Follow‐up evaluation was performed at approximately 1 month. Telephone interview of the owner was used for long‐term assessment (median follow‐up for 17 surviving dogs was 10.5 months).

Results— Adequate reduction and stabilization was achieved in all dogs based on radiographic assessment immediately after surgery. Improved neurologic outcome occurred in 16 dogs at 1 month and in 15 dogs at follow‐up; 2 dogs died of post‐operative complications within 24 hours of surgery. One dog was euthanatized at the owners' request because of recurrent neck pain associated with implant failure after 1 month. Two dogs required surgery to remove broken and migrated implants, but further stabilization was not necessary.

Conclusions— Adequate stabilization and improved neurologic outcome was achieved in most dogs. However, on account of the small size of the study and the variable neurologic signs of the dogs on admission, the surgical technique described could not be compared to those previously reported.

Clinical Relevance— The surgical technique described is an effective means of surgical treatment for atlantoaxial subluxation.
Pre‐Emptive Epidural Ketamine or S(+)‐Ketamine in Post‐incisional Pain in Dogs: A Comparative Study
Authors: Duque M Juan Carlos , Valadão Carlos A.A. , Farias Anderson , De Almeida Ricardo M. , Oleskovicz Nilson
Published: July 2004

Objective— To compare the pre‐emptive analgesic effects of epidural ketamine or S(+)‐ketamine on post‐incisional hyperalgesia.

Study Design— Prospective randomized study.

Animals— Twenty‐four mongrel dogs (1–5 years, weighing 11.9±1.8 kg).

Methods— Dogs were anesthetized with propofol (5 mg/kg intravenously) and a lumbosacral epidural catheter was placed. Dogs were randomly allocated to 3 groups, each with 8 dogs. The control group (CG) was administered saline solution (0.3 mL/kg); the ketamine group (KG) ketamine (0.6 mg/kg); and the S(+)‐ketamine group (SG) S(+)‐ketamine (0.6 mg/kg). The final volume was adjusted to 0.3 mL/kg in all groups. Five minutes after the epidural injection a surgical incision was made in the common pad of the right hind limb and was immediately closed with simple interrupted nylon suture. Respiratory (RR) and heart (HR) rates, rectal temperature (T), sedation (S), lameness score, and mechanical nociceptive threshold by von Frey filaments were evaluated before the propofol anesthesia and at 15, 30, 45, 60, 75, and 90 minutes and then at 2, 4, 6, 8, 12, and 24 hours after epidural injection.

Results— There were no differences in RR, HR, T, or S between groups. Motor blockade of the hind limbs was observed during 20±3.6 minutes in KG and during 30.6±7.5 minutes in SG (mean±SD). Mechanical force applied to obtain an aversive response was higher from 45 minutes to 12 hours in KG and from 60 to 90 minutes in SG, when compared with CG.

Conclusions— Pre‐emptive epidural ketamine induced no alterations in RR and HR, and reduced post‐incisional hyperalgesia for a longer time than did S(+) ketamine.

Clinical Relevance— Although anesthetic and analgesic potency of S(+) ketamine is twice that of ketamine, the racemic form is seemingly better for post‐incisional hyperalgesia.
Buccal Mucosal Graft Urethroplasty for Reversal of a Perineal Urethrostomy in a Goat Wether
Authors: Gill Marjorie S. , Sod Gary A.
Published: July 2004

Objective— To describe the use of buccal mucosa as a urethral graft for reversal of perineal urethrostomy (PU) in a castrated male goat.

Study Design— Clinical case report.

Sample Population— One client‐owned castrated male goat.

Results— An 8‐month‐old Pygmy cross wether was admitted for urolithiasis and PU stricture. After repeated unsuccessful attempts at urethrostomy reversal and urethral reconstruction, a buccal mucosal graft was used for urethroplasty. Buccal mucosa proved to be an excellent graft for urethral repair. Normal urination has occurred through the reconstructed region for at least 24 months.

Conclusions— Buccal mucosa worked well as a graft for urethroplasty and PU reversal.

Clinical Relevance— Grafting with buccal mucosa may also prove useful in other urethral repair techniques in small ruminants.
Biomechanical and Clinical Evaluation of a Modified 3‐Loop Pulley Suture Pattern for Reattachment of Canine Tendons to Bone
Authors: Moores Andy P. , Comerford Eithne J. , Tarlton John F. , Owen Martin R.
Published: July 2004

Objective— To describe a modified 3‐loop pulley suture pattern for the reattachment of canine tendons to bone along with a biomechanical comparison with the locking‐loop suture.

Study Design— In vitro biomechanical study and clinical case report.

Animals or Sample Population— Biomechanical study: 10 paired gastrocnemius tendons and calcaneii harvested from 5 canine cadavers. Case report: a Doberman with avulsion of the gastrocnemius tendon of insertion.

Methods— Biomechanical study: paired tendons were reattached to the calcaneus with either a modified 3‐loop pulley pattern or a locking‐loop pattern. Tensile loading to failure was performed. A direct, non‐contact, method of gap measurement, using digital video, was used to measure gap formation. Load required to initiate gap formation (defined as load at a 1 mm gap) and to produce a 3 mm gap was evaluated in addition to maximum load and gap at failure.

Results— Mean (±SEM) 1 mm gap loads were 31.0±4.2 and 17.2±2.5 N, mean 3 mm gap loads were 49.1±2.4 and 28.9±3.2 N, and mean maximum loads were 72.9±4.3 and 55.8±2.2 N for the modified 3‐loop pulley suture and the locking‐loop suture, respectively. These differences were statistically significant (P<.05). The gap at failure was similar for both repairs. The clinical case remained sound 7 months postoperatively.

Conclusions— A modified 3‐loop pulley pattern is biomechanically superior to a locking‐loop pattern for reattachment of the canine gastrocnemius tendon to bone and may be suitable for clinical use.

Clinical Relevance— Tendon repairs with a gap >3 mm are reported to be at increased risk of rupture during the first 6 weeks postoperatively. A modified 3‐loop pulley pattern resists gap formation better than a locking‐loop pattern.
Performance after Partial Arytenoidectomy without Mucosal Closure in 27 Thoroughbred Racehorses
Authors: Barnes Amy J. , Slone Donnie E. , Lynch Tim M.
Published: July 2004

Objective—To examine the effect of partial arytenoidectomy without mucosal closure on postoperative racing performance and long‐term complications in Thoroughbred racehorses treated for laryngeal hemiplegia, arytenoid chondropathy, or failed laryngoplasty.

Study Design—Retrospective study.

Animals—Twenty‐seven Thoroughbred racehorses.

Methods—Medical records of Thoroughbred racehorses that had partial arytenoidectomy without mucosal closure between 1992 and 2002 were reviewed. Horses were divided into groups: horses that had not raced (Group 1) and those that had raced (Group 2) before surgery. Lifetime race records were compared between groups. A standard starts index (SSI) and performance index (PI) were used for Groups 1 and 2, respectively, to objectively evaluate each horse's postoperative performance. Telephone interviews of owners and trainers were used for subjective performance evaluation and to determine prevalence of long‐term complications.

Results—Eleven (61%) Group 1 and 7 (78%) Group 2 horses raced and earned money after surgery. All Group 1 horses that raced performed at a level lower than the national average. Only 1 Group 2 horse had an improved PI score postoperatively.

Conclusions—Thoroughbred racehorses have a fair prognosis for racing successfully after partial arytenoidectomy without mucosal closure.

Clinical Relevance—This technique may be a practical alternative to primary mucosal closure, would decrease surgical time, and avoid some problems reported with primary mucosal closure.
In Vitro Efficacy of a Polyhexamethylene Biguanide‐Impregnated Gauze Dressing Against Bacteria Found in Veterinary Patients
Authors: Lee William R. , Tobias Karen M. , Bemis David A. , Rohrbach Barton W.
Published: July 2004

Objective—To evaluate the in vitro efficacy of polyhexamethylene biguanide (PHMB)‐impregnated gauze dressing in limiting the growth of bacteria both within and underneath the dressing.

Study Design—In vitro study.

Methods—Squares of PHMB‐impregnated and control gauze were placed on agar plates inoculated with 1 of 11 bacterial species, including 8 multi‐resistant organisms. Growth under the gauze was assessed qualitatively after 24‐hour incubation. Repeated use of sponges was used to evaluate residual inhibitory activity againstMicrococcus luteaandStaphylococcus schleiferiss.schleiferi. In a second procedure, PHMB‐impregnated and control gauze squares were placed in sterile plastic wells and inoculated with 1 of 5 bacterial species, includingPseudomonasspp. andKlebsiellaspp. Inhibition of bacterial growth within and underneath the dressing after 24‐hour incubation was evaluated by quantifying the numbers of bacteria on the well floor and within each square.

Results—PHMB‐impregnated gauze provided greater inhibition of growth of 4/4 Gram‐positive species and 2/6 Gram‐negative species on inoculated plates compared with control gauze. Residual inhibitory activity of PHMB‐impregnated gauze was significantly greater againstM. luteaon all days and againstS. schleiferiss.schleiferion days 1 and 4 compared with control. No bacteria were recovered from inoculated PHMB‐impregnated gauze squares placed in sterile wells or from the well floor underneath. More than 9 × 105colony‐forming units (CFU) were recovered from inoculated control samples placed in sterile wells and more than 8.4 × 104CFU were recovered from control well floors.

Conclusion—PHMB‐impregnated gauze dressing, when placed on inoculated agar plates, reduces growth of underlying bacteria, particularly Gram‐positive species. Wet‐inoculated PHMB‐impregnated dressing prevents growth of Gram‐positive and Gram‐negative bacteria both within and underneath the dressing.

Clinical Relevance—PHMB‐impregnated dressings may be useful for reducing contamination of underlying wounds by bacterial pathogens.
Use of Laparotomy in a Staged Approach for Resolution of Bilateral or Complicated Perineal Hernia in 41 dogs
Authors: Brissot Hervé N. , Dupré Gilles P. , Bouvy Bernard M.
Published: July 2004

Objective—To evaluate the value of laparotomy as the initial step in the treatment of bilateral or complicated perineal hernia (PH) in dogs.

Study Design—Retrospective study.

Animals or Sample Population—Forty‐one dogs with PH.

Methods—Dogs with bilateral or complicated PH treated by a 2‐step approach between November 1997 and December 2001 were studied. Inclusion criteria for complicated PH were: recurrence of PH, unilateral PH with a major rectal dilatation, PH with a concurrent surgical prostatic disease, and PH with retroflexed bladder. Colopexy, vas deferens pexy, cystopexy, and prostatic omentalization were performed during laparotomy as needed. Later, PH was performed by internal obturator muscle flap (IOMF) or if there was a perineal rent or weakness on the contralateral side, appositional herniorrhaphy was performed. Outcome was followed for ≥6 months.

Results—PH were bilateral (20 dogs) or unilateral (21). Twenty‐one (51%) dogs had prostatic disease (clinical or ultrasonography diagnosis; 17 confirmed histologically) and 12 (29%) had urinary bladder retroflexion. Forty‐one colopexies, 32 vas deferens pexies, 6 cystopexies, and 9 prostatic surgeries (omentalization or perineal cyst resection) were performed. PH was performed 2–20 days (median, 6 days) later: 61 IOMF transpositions, 13 appositional. Mean follow‐up time was 26.6 months (range, 6–54 months, median, 27 months). PH was resolved in 37 (90%) dogs; 4 dogs had recurrence, and all occurred within 6 months. Thirty‐eight (92%) dogs had an improved quality of life (good in 34 dogs, fair in 4 dogs). Wound complications occurred in 7 dogs (17%). Postoperative urine dribbling occurred in 15 dogs (37%) and was irreversible in 7 dogs (17%). Postoperative fecal straining persisted in 18 dogs (44%), and was permanent in 4 dogs (10%). Fecal incontinence did not occur.

Conclusions—In bilateral or complicated PH, fixation of the urinary bladder and colon, and treatment of prostatic disease increase the chances of resolution. Emptying of the perineal space by organ pexy allows improved observation during herniorrhaphy. Despite a 90% clinical resolution, dogs with complicated PH treated by a 2‐step protocol may have persistent urinary and fecal disorders.

Clinical Relevance—To improve the prognosis of bilateral or complicated PH, investigation and treatment of concomitant lesions (rectal, prostatic, bladder) should be part of a rational surgical strategy using a 2‐step protocol.
Area moments of inertia as a measure of the mandible stiffness of the implant patient
Authors: Hansson Stig , Ekestubbe Annika
Published: July 2004

Abstract: It was hypothesized that the bending stiffness of the mandible is an important biomechanical parameter in implant dentistry. It was shown how this bending stiffness can be estimated by means of the principal area moments of inertia of the cortical and cancellous cross‐sections as obtained by computed tomography, some image processing and subsequent calculation. It was found that the contribution of the cancellous bone to the bending stiffness is normally insignificant and that the principal area moments of inertia of the cortical cross‐section show large variations, depending on the degree of resorption. It was furthermore found that the variations in the principal area moments of inertia of the cortical cross‐section in one and the same potential implant patient were minor. Finally, in a three‐dimensional finite element study, it was found that the peak bone stresses adjacent to implants, resulting from a standardized load at the distal end of an implant‐supported bridge, were inversely related to the magnitude of the principal area moment of inertia about the horizontal axis of the cortical cross‐section. It was concluded that the principal area moments of inertia of the cortical cross‐section and the angulation of the principal axes of inertia might be useful as a quantitative characterization of the mandible stiffness in clinical research and perhaps also in clinical practice.
Biomechanical aspects of marginal bone resorption around osseointegrated implants: considerations based on a three‐dimensional finite element analysis
Authors: Kitamura Eriko , Stegaroiu Roxana , Nomura Shuichi , Miyakawa Osamu
Published: July 2004

Objectives: Although bone loss around implants is reported as a complication when it progresses uncontrolled, resorption does not always lead to implant loss, but may be the result of biomechanical adaptation to stress. To verify this hypothesis, a three‐dimensional finite element analysis was performed and the influence of marginal bone resorption amount and shape on stress in the bone and implant was investigated.

Material and methods: A total of nine bone models with an implant were created: a non‐resorption (Base) model and eight variations, in which three different resorption depths were combined with pure vertical or conical (vertical–horizontal) resorption. Axial and buccolingual forces were applied independently to the occlusal node at the center of the superstructure.

Results: Regardless of load direction, bone stresses were higher in the pure vertical resorption (A) models than in the Base model, and increased with resorption depth. However, cortical bone stress was much lower in the conical resorption models than in both the Base and A models of the same resorption depth. An opposite tendency was observed in the cancellous bone under buccolingual load.

Under buccolingual load, highest stress in the implant increased linearly with the resorption depth for all the models and its location approached the void existing below the abutment screw.

Conclusions: The results of this analysis suggest that a certain amount of conical resorption may be the result of biomechanical adaptation of bone to stress. However, as bone resorption progresses, the increasing stresses in the cancellous bone and implant under lateral load may result in implant failure.
Dynamic fatigue resistance of implant–abutment junction in an internally notched morse‐taper oral implant: influence of abutment design
Authors: Çehreli Murat Cavit , Akça Kıvanç , İplikçioğlu Haldun , Şahin Saime
Published: July 2004

Purpose: To compare dynamic fatigue resistance of one‐ and two‐piece abutments connected to internally notched morse‐taper oral implants.

Material and methods: Sixteen synOcta® ITI® implants were tightened into two metal models. SynOcta® abutments for cement‐retained restorations and solid abutments were divided into two equal groups and were torque‐tightened into the implants. Each implant received a cement‐retained crown. Cyclic dynamic axial and lateral peak loads of 75±5 N were applied on the implants for a duty of 500,000 cycles at 0.5 Hz, and at an angle of 20°. Prior to the experiments and at each 100,000 cycles of loading, periotest values (PTVs) were measured. Removal torque values (RTVs) of the abutments were also measured with a custom‐made torque device at the termination of the experiment.

Results: All abutments and implants were clinically immobile and without any signs of mechanical failure. The final PTVs for both abutments were similar and the difference between groups was insignificant (P>0.05). The RTVs of solid abutments were significantly higher than synOcta® abutments (P<0.05).

Conclusion: Predictable long‐term clinical results can be achieved with solid abutments and synOcta® abutments for cement‐retained restorations. Solid abutments possess higher removal torque resistance than synOcta® abutments when connected to synOcta® ITI® implants.
A controlled clinical trial of implant‐retained mandibular overdentures: 10 years' results of clinical aspects and aftercare of IMZ implants and Brånemark implants
Authors: Meijer Henny J. A. , Raghoebar Gerry M. , Van't Hof Martin A. , Visser Anita
Published: July 2004

Abstract: The aim of this prospective randomized controlled clinical trial was to evaluate the clinical outcomes and prosthetic aftercare of edentulous patients with a mandibular overdenture retained by two IMZ implants or two Brånemark implants during a 10‐year period. Patients were allocated to the IMZ group (n=29) or the Brånemark group (n=32) by a computerized balancing method. In the IMZ group, four implants were lost during the 10‐year follow‐up (survival rate: 93%). In the Brånemark group, nine implants were lost (survival rate: 86%). All patients were re‐operated successfully. Multiple prosthetic revisions were necessary in both groups; especially the precision attachment system in the overdenture (23% of the total number of revisions) and the denture base and teeth (26% of the total number of revisions) were subject to frequent fracture. From this study, it can be concluded that both the IMZ implant and the Brånemark implant systems supporting an overdenture are functioning well after 10 years of follow‐up. There are no indications of a worsening of clinical or radiographical state after 10 years.
Force transmission of one‐ and two‐piece morse‐taper oral implants: a nonlinear finite element analysis
Authors: Cavit Çehreli Murat , Akça Kıvanç , İplikçioğlu Haldun
Published: July 2004

Purpose: To compare force transmission behaviors of one‐piece (1‐P) and two‐piece (2‐P) morse‐taper oral implants.

Material and methods: A three‐dimensional finite element model of a morse‐taper oral implant and a solid abutment was constructed separately. The implant–abutment complex was embedded in a Ø 1.5 cm × 1.5 cm acrylic resin cylinder. Vertical and oblique forces of 50 N and 100 N were applied on the abutment and solved by two different analyses. First, contact analysis was performed in the implant–abutment complex to evaluate a 2‐P implant. Then, the components were bonded with a separation force of 1020 N to analyze a 1‐P implant.

Results: Von Mises stresses in the implant, principal stresses, and displacements in the resin were the same for both designs under vertical loading. Under oblique loading, principal stresses and displacement values in the resin were the same, but the magnitudes of Von Mises stresses were higher in the 2‐P implant. The principal stress distributions around both implants in the acrylic bone were similar under both loading conditions.

Conclusion: 2‐P implants experience higher mechanical stress under oblique loading. Nevertheless, the 1‐P‐ or 2‐P morse‐taper nature of an implant is not a decisive factor for the magnitude and distribution of stresses, and displacements in supporting tissues.
Impact of IL‐1 genotype and smoking status on the prognosis of osseointegrated implants
Authors: Gruica Boris , Wang Hwa‐Ying , Lang Niklaus P. , Buser Daniel
Published: July 2004

Abstract
Aim: This study evaluated the impact of the IL‐1 genotype and smoking status on the prognosis and development of complications of osseointegrated implants.

Material and methods: The clinical charts of 180 consecutively admitted patients were analyzed with respect to the occurrence of biological complications in conjunction with oral implants. Biologic complications were defined as clinical conditions with suppuration from the peri‐implant sulcus, development of a fistula or peri‐implantitis with radiologic bone loss. All patients had received one or more ITI® dental implants, which had been in function for at least 8 (range: 8–15) years. This patient population had received 292 implants. From these, 51 implants in 34 patients showed late (infectious) biologic complications, and 241 implants had survived without any biologic complications at all.

Results: Of the 180 patients, 53 were smokers, who were subdivided in a series of classes according to their intensity of smoking and 127 were never smokers. Sixty‐four of 180 (36%) patients tested positive for the IL‐1 genotype polymorphism. This prevalence corresponds to previous reports for the prevalence of European descent populations. The results for the non‐smoking group indicated no significant correlation between implant complications and a positive IL‐1 genotype. However, there was a clear association for heavy smokers between a positive IL‐1 genotype and implant complications. 6 of 12 or half of the heavy smokers and IL‐1 genotype‐positive patients had either an implant failure, i.e. loss of implant, or a biologic complication during the follow‐up period.

Conclusions: These findings have led to the conclusion that there is a synergistic effect between a positive IL‐1 genotype and smoking that puts dental implants at a significantly higher risk of developing biologic complications during function.
Cement fixation and screw retention: parameters of passive fit
Authors: Heckmann Siegfried M. , Karl Matthias , Wichmann Manfred G. , Winter Werner , Graef Friedrich , Taylor Thomas D.
Published: July 2004

Abstract: It is generally assumed that passively fitting superstructures are a prerequisite for long‐lasting implant success. In the study presented, the strain development of three‐unit implant fixed partial dentures (FPDs) was evaluated at the bone surrounding the implant and on the superstructure using a strain gauge technique. Six groups of three‐unit FPDs representing the commonly used techniques of bridge fabrication were investigated with 10 samples each, in order to quantify the influence of impression technique, mode of fabrication and retention mechanism on superstructure fit. Two ITI implants (Straumann, Waldenburg, Switzerland) were anchored in a measurement model according to a real‐life patient situation and strain gauges were fixed mesially and distally adjacent to the implants and on the bridge pontics. The developing strains were recorded during cement setting and screw fixation. For statistical analysis, multivariate two sample tests were performed setting the level of significance at P=0.1. None of the investigated bridges revealed a truly passive fit without strains occurring. About 50% of the measured strains were found to be due to impression taking and model fabrication, whereas the remaining 50% were related to laboratory inaccuracies. The two impression techniques used did not reveal any significant differences in terms of precision. Both modes of fixation – i.e. cement and screw retention – provoked equally high stress levels. In the fabrication of screw‐retained FPDs, similar results were obtained from the use of burn‐out plastic copings and the technique of casting wax moulds to premachined components. Bonding bridge frames onto gold cylinders directly on the implants significantly reduces strain development.
Astra Tech and Brånemark system implants: a 5‐year prospective study of marginal bone reactions
Authors: Åstrand Per , Engquist Bo , Dahlgren Simon , Gröndahl Kerstin , Engquist Eva , Feldmann Hartmut
Published: July 2004

Abstract: This paper describes the 5‐year results of a comparative study between Astra Tech and Brånemark system implants. The aim was to compare the systems primarily with regard to bone level changes, and also with regard to other variables of interest. Sixty‐six patients with edentulous jaws were included in the study. Randomisation schedules were used to allocate the patients to the two implant systems. 184 Astra Tech implants with a titanium‐blasted surface and 187 Brånemark implants with a turned surface were used. The implants were inserted with a two‐stage technique and the insertion followed the routines for the respective implant system. All patients were provided with full‐arch fixed bridges. All patients were followed up with clinical and radiographic examinations from fixture insertion to the 5‐year follow‐up. The total mean bone level change in the upper jaw between fixture insertion and the 5‐year examination was −1.74±0.45 mm at the Astra implants and −1.98±0.21 at the Brånemark implants. The corresponding values for the lower jaw were −1.06±0.19 for Astra and −1.38±0.17 for Brånemark. The major postoperative changes of the marginal bone level took place between fixture insertion and baseline. During this period, there was also a different pattern of bone remodelling between the implant systems. Between baseline (prosthesis connection) and the 5‐year examination, the marginal bone level changes were small, with no difference between the implant systems. The implant stability was examined with the supraconstructions removed. At the 5‐year examination, the survival rate for Astra Tech implants was 98.4% and for the Brånemark implants it was 94.6%. The difference was not statistically significant.
A comparative study of barrier membranes as graft protectors in the treatment of localized bone defects
Authors: Stavropoulos Franci , Dahlin Christer , Ruskin James D. , Johansson Carina
Published: July 2004

Abstract: Guided bone regeneration is a predictable and well‐documented surgical approach for the treatment of deficient alveolar ridges prior to endosseous implant placement. The purpose of this study was to compare a new resorbable membrane (GORE RESOLUT ADAPT Regenerative Membrane, i.e. 67% glycolide (PGA) : 33% trimethyline carbonate (TMC)) with Bio‐Gide®, a resorbable collagen membrane. Five canines were used in the study. Three saddle‐type osseous defects were created bilaterally in edentulous areas of the mandible. The defects were filled with assayed, canine demineralized freeze‐dried bone (DFDB) in a thermoplastic gelatin matrix. Using a randomized block design, four sites were covered with PGA : TMC membranes of four different porosities, one site was covered with a collagen membrane and one site consisted of DFDB alone (control). At 3 months, the animals were euthanized and the mandibles were removed en bloc for laboratory processing. A total of 30 sites were reviewed microradiographically and underwent histomorphometric analysis for bone regeneration, soft tissue presence and remaining graft material. All sites exhibited uneventful healing. A significantly higher percentage of bone regeneration was seen in the sites protected by the PGA : TMC membrane. A higher component of soft tissue was visible beneath the collagen membrane as compared with the PGA : TMC membrane. The control sites exhibited noticeable deformation of the regenerated bone secondary to collapse of the overlying periosteum. The authors conclude that the PGA : TMC membrane protected the DFDB‐filled defect and allowed a greater amount of bone regeneration than the defect protected by the collagen membrane or the control.
Patient experience of, and satisfaction with, delayed‐immediate vs. delayed single‐tooth implant placement
Authors: Schropp Lars , Isidor Flemming , Kostopoulos Lambros , Wenzel Ann
Published: July 2004

Objectives: Recent investigations have focused on patients' subjective assessment of implant treatment. The aim of this study was to compare the patients' experience of surgical and prosthetic procedures, as well as satisfaction with function and aesthetics following single‐tooth replacements mounted to early vs. delayed placed dental implants.

Material and methods: Forty‐six patients were treated with a single‐tooth implant in the anterior or premolar region. Twenty‐three implants were placed on average 10 days after tooth extraction (Im), while 23 implants were placed approximately 3 months after tooth extraction (De). Forty‐one patients completed a questionnaire regarding the treatment using visual analog scales (VAS) and check boxes 16–18 months after delivery of the restoration.

Results: In all, 90% of the respondents rated 88 or higher on the VAS regarding satisfaction with the crown. Satisfaction with the restoration in general and the appearance was significantly greater in the Im group than in the De group (96 vs. 93; P<0.02). Assessment of the implant surgery was not significantly different between the delayed‐immediate and the delayed group. Approximately 25% of the patients experienced unpleasantness in relation to the prosthetic procedures, and in 8 of 11 cases, impression taking was the cause. When evaluating satisfaction with the overall implant treatment, the VAS scores for the delayed‐immediate group were significantly higher than for the delayed group (96 vs. 90; P<0.02).

Conclusion: The patients in the present study were highly satisfied with the outcome of the treatment and experienced it to be without significant unpleasantness irrespective of the treatment concept.
Resonance frequency analysis of implants subjected to immediate or early functional occlusal loading
Authors: Glauser Roland , Sennerby Lars , Meredith Neil , Rée Andreas , Lundgren AnnaKarin , Gottlow Jan , Hämmerle Christoph H.F.
Published: July 2004

Objectives: The objective of this study was to analyze the development of implant stability by repeated resonance frequency analysis (RFA) measurements during 1 year in 23 patients treated according to an immediate/early‐loading protocol. The objective was also to evaluate the possible differences between failing and successful implants.

Material and methods: Eighty‐one Brånemark System implants were placed in 23 patients for immediate/early‐occlusal loading in all jaw regions. Thirty of the implants were placed in extraction sockets and 62 were subjected to GBR procedures. Apart from clinical and radiographic examinations, the patients were followed with RFA at placement, prosthesis connection and after 1–3, 6 and 12 months. Statistical analyses were carried out to study the possible differences between implants that failed during the study period and implants that remained successful.

Results: Nine implants failed (11.2%) during the 1 year of loading. RFA showed a distinct different pattern between the implants that remained stable and the implants that were lost. The implants that failed during the course of the study showed a significantly lower stability already after 1 month.

Conclusion: Within the limitations of this study, it is concluded that failing implants show a continuous decrease of stability until failure. Low RFA levels after 1 and 2 months seem to indicate an increased risk for future failure. This information may be used to avoid implant failure in the future by unloading implants with decreasing degree of stability with time as diagnosed with the RFA technique.