PubMed Health⌕ Search

Biomedical subjects

William Becker

Publications and source records attributed to William Becker.

17 recordsLinked to original sources
PubMed2006

Histologic evaluation of implants following flapless and flapped surgery: a study in canines.

BACKGROUND: Flapless surgery requires penetration of the alveolar mucosa and bone without reflection of mucoperiosteal flaps. Do these techniques force gingival tissue or foreign materials into osteotomies? If so, do such tissues or materials interfere with osseointegration? A proof-of-principle study using a canine model attempted to answer these questions. METHODS: Five young adult Hound Labrador mongrel dogs received implants with a moderately roughened surface by anodic oxidation using flapless or conventional one-stage (control) surgery in contralateral jaw quadrants. The implants were placed into the osteotomies, and the international stability quotient (ISQ) was recorded using resonance frequency analysis. These measurements were repeated following a 3-month healing interval when the animals were euthanized, and implants and surrounding tissues were retrieved and processed for histologic analysis. RESULTS: The implants were stable upon insertion and demonstrated increased stability at 3 months without significant differences between surgical protocols. The histologic evaluation showed high bone-implant contact (flapless surgery: 54.7% +/- 8.4%; control: 52.2% +/- 13.0%; P >0.05) without evidence of gingival tissue or foreign body inclusions. There were no significant differences in marginal bone levels between the surgical protocols. Post-insertion and at 3 months, ISQ values depended on the amount of torque delivered. Immediately post-insertion, for every 1-unit increase in torque value, the ISQ increased by 0.3 (95% confidence interval: 0.1 to 0.4; P = 0.0043). Three months postoperatively, for every one-unit increase in torque the ISQ value decreased 0.2 (95% confidence interval: -0.4 to -0.1; P = 0.0012). The effect of torque on ISQ values was independent of treatment effects and remained significant after adjustment for treatment. CONCLUSIONS: The results suggest that implants placed without flap reflection remain stable and exhibit clinically relevant osseointegration similar to when implants are placed with flapped procedures. Greater torque at implant placement resulted in less implant stability at 3 months.

Alveolar Process↗
PubMed2005

A descriptive study on retrieved non-threaded and threaded implant designs.

OBJECTIVES: In the light microscope compare the amount of bone saucerization for non-threaded cylindrical and threaded implant designs in retrieved samples from patients. MATERIAL AND METHOD: Consecutively received retrieved oral implants from 117 patients, whereof 85 non-threaded cylindrical and 85 Brånemark implants, have been included in the study. For 75 non-threaded cylindrical and 46 Brånemark implants was the entire implant length available for calculation. Undecalcified ground sections were investigated in the light microscope with calculation of percentage of implant length coronal to the first bone-implant contact and percentage of bone to implant contact. RESULTS: Mean value for implant length coronal to first bone-implant contact was 65%, standard error of the mean (SEM) 3 (range 0-100%), for non-threaded cylindrical implants and 43%, SEM 6 (range 0-100%) for Brånemark implants. Mean values of bone contact along the entire implant length was 23%, SEM 2 (range 0-65%), for the non-threaded cylindrical implants and 33%, SEM 5 (range 0-93%) for the Brånemark implants. CONCLUSION: Within the limitations of this retrospective, retrieval study non-threaded cylindrical implants demonstrated a greater bone saucerization when evaluated in the light microscope.

Adult↗
PubMed2005

Minimally invasive flapless implant surgery: a prospective multicenter study.

BACKGROUND: Placement of implants with a minimally invasive flapless approach has the potential to minimize crestal bone loss, soft tissue inflammation, and probing depth adjacent to implants and to minimize surgical time. PURPOSE: The aim of this multicenter study was to evaluate implant placement using a minimally invasive one-stage flapless technique up to 2 years. MATERIALS AND METHODS: Fifty-seven patients ranging in age from 24 to 86 years were recruited from three clinical centers (Tucson, AZ, USA; Tel Aviv, Israel; Göteborg, Sweden). Seventy-nine implants were placed. A small, sharp-tipped guiding drill was used to create a precise, minimally invasive initial penetration through the mucosa and into bone (Nobel Biocare, Yorba, Linda, CA, USA). Implants were placed according to the manufacturer's instructions, with minimal countersinking. The parameters evaluated were total surgical time, implant survival, bone quality and quantity, implant position by tooth type, depth from mucosal margin to bone crest, implant length, probing depth, inflammation, and crestal bone changes. At 2 years, for 79 implants placed in 57 patients, the cumulative success rate using a minimally invasive flapless method was 98.7%, indicating the loss of 1 implant. Changes in crestal bone for 77 baseline and follow-up measurements were insignificant (radiograph 1: mean 0.7 mm, SD 0.5 mm, range 2.8 mm, minimum 0.2 mm, maximum 3.0 mm; radiograph 2: mean 0.8 mm, SD 0.5 mm, range 3.4 mm, minimum 0.12 mm, maximum 3.5 mm). Using descriptive statistics for 78 patients (one implant lost), mean changes for probing depth and inflammation were clinically insignificant. The average time for implant placement was 28 minutes (minimum 10 minutes, maximum 60 minutes, SD 13.1 minutes). Average depth from mucosal margin to bone was 3.3 mm ( SD 0.7 mm, minimum 2 mm, maximum 5 mm, range 3 mm). Thirty-two implants were placed in maxillae and 47 in mandibles. CONCLUSIONS: The results of this study demonstrate that following diagnostic treatment planning criteria, flapless surgery using a minimally invasive technique is a predictable procedure. The benefits of this procedure are lessened surgical time; minimal changes in crestal bone levels, probing depth, and inflammation; perceived minimized bleeding; and lessened postoperative discomfort.

Adult↗
PubMed2005

Implant stability measurements for implants placed at the time of extraction: a cohort, prospective clinical trial.

BACKGROUND: Studies indicate that implants placed at the time of extraction have high success rates. Implants must be stable at the time of insertion. Presently there are no data indicating the degree of implant stability when implants are placed at the time of extraction. This study evaluated changes in stability of implants from implant placement to abutment connection utilizing resonance frequency analysis (RFA). The unit of measurement was the international stability quotient (ISQ). METHODS: Prior to treatment, patients were given medical history and dental evaluations. Periapical and panogram radiographs were taken. Fifty-two patients requiring extraction of one or two teeth and implant placement immediately after extraction were enrolled in this study. Under conscious sedation and local anesthesia or local anesthesia alone, teeth were atraumatically removed and the extraction sockets were debrided. A total of 73 dental implants (57 in the maxilla, 16 in the mandible) were placed. Using a one-stage approach, all implants were placed within the patient's alveolar envelope and were never placed directly into extraction sockets. All implants were placed into contained extraction sites. Bone augmentation procedures were not performed. After implant insertion, the RFA electronic transducer was attached to the head of the implant with the retaining screw. The device was attached to a computer designed to register RFA scores in ISQ units. RFA measurements were taken at implant placement and abutment connection. Bone qualities, quantity, implant length and width as well as site of placement were recorded. RESULTS: The average interval between implant insertion and abutment connection was 5.6 months (SD 2.05). Two implants were lost between implant insertion and 1 year. At 2 to 3 years, the cumulative survival was 97.2%. Resonance frequency measurements at implant placement showed a mean primary stability of 62.0 (SE 1.1; range 43 to 83 ISQ) and a mean secondary stability after 1 year of 64.0 (SE 1.2; range 40 to 98 ISQ) for all implants. The increase was marginally significant (generalized estimating equation z-statistic = 1.79; P value = 0.07). CONCLUSIONS: Implants placed at the time of extraction and inserted into native bone and not directly into extractions sockets have a high degree of initial stability as evidenced by RFA measurements. Implants with initial high ISQ levels revealed a slight drop in levels over time, while implants with levels lower than 60 had increases in levels between implant insertion and abutment connection. At 2 to 3 years the cumulative survival rate was 97.2%.

Bone Density↗
PubMed2005

Immediate implant placement: diagnosis, treatment planning and treatment steps/or successful outcomes.

Diagnosis and treatment planning are key factors in achieving successful outcomes after placing and restoring implants placed immediately after tooth extraction. The efficacy of immediate implant placement has been established and shown to be predictable if reasonable guidelines are followed. Some or all of the following suggestions, depending on individual circumstances should be considered when evaluating a patient for dental implants: thorough medical and dental histories, clinical photographs, study casts, periapical and panogram radiographs, as well as a linear tomography or computerized tomography of the proposed implant sites. Reasons for tooth extraction include, but are not limited to, insufficient crown to root ratios, remaining root length, periodontal attachment levels, periodontal health of teeth adjacent to the proposed implant sites, unrestorable caries, root fractures with large endodontic posts, root resorption, teeth with deep furcation invasions being considered as abutments for fixed partial dentures, and questionable teeth in need of endodontic retreatment. Teeth requiring root amputations, hemisections or advanced periodontal procedures may have a questionable prognosis, and patients should be given the implant option before these procedures are implemented. Similarly, nonvital teeth, fractured at the gingival margin with roots shorter than 13 mm should be considered for the implant option. This review will describe the steps for immediate implant placement at the time of extraction as well as the "gap" and socket preservation.

Animals↗
PubMed2005

Fibrin sealants in implant and periodontal treatment: case presentations.

Sutures are traditionally used to close flaps associated with periodontal and implant procedures. When implants are placed in the esthetic zone or when periodontal plastic surgical procedures are performed, fibrin sealants may be a viable alternative to closing flaps with sutures. This article describes the history of using fibrin sealants in medicine and dentistry and discusses their uses. Patients treated with sealants are presented.

Adult↗
PubMed2003

Early functional loading in the fully edentulous mandible after mandibular resection and reconstruction due to an ameloblastoma: case report.

BACKGROUND: Immediate or early functional loading of implants in fully edentulous mandibles can enhance patient comfort and the ability to masticate within a few days after implant placement. Recently there has been evidence that this method of restoring edentulous mandibles is predictable. PURPOSE: The goal of this case report is to present the treatment of a patient diagnosed with a large ameloblastoma in the mandible. After removal of the tumor and mandibular reconstruction, the patient had complete anesthesia in the right mandible, with an alveolar ridge deformity. METHODS: Two years after removal of an ameloblastoma in the right mandibluar sextant, five implants were installed between the mental foramina. One implant was installed for safety reasons in the event one of the others was lost. This implant remains buried. A denture was used as a drilling guide. Abutments were attached to the implants, and impression copings were fixed to the abutments. The denture was used for the "pickup" impression. Flaps were sutured, maintaining exposure of the abutments. In the laboratory, gold cylinders were heat cured to the tissue side of the denture. The cylinders were attached to the cast with laboratory screws. The gold cylinders were heat cured to the intaglio side of the denture. Five days after implant placement, the nonmetal reinforced acrylic denture was fixed to the implants with laboratory screws. The bridge is removed annually, and the implants are examined for mobility and periapical radiographs are taken. RESULTS: The patient has worn the prosthesis for 2.5 years without loss of implants and without breakage of the nonmetal reinforced denture. At 2.5 years the implants are stable, implant sites demonstrate stable crestal bone, and the patient is eating comfortably and without limitations. CONCLUSION: Early functional loading of implants in the edentulous mandible may offer patients the option of wearing implant-supported prosthesis immediately or shortly after implant insertion.

Acrylic Resins↗
PubMed2003

Periodontal referral patterns, 1980 versus 2000: a preliminary study.

BACKGROUND: A review of the periodontal literature offers little information concerning trends in referral patterns of patients for periodontal therapy. Over the last 2 decades, there has been a significant increase in the knowledge base concerning inflammatory periodontal disease. It might be assumed that the collective advances in knowledge have impacted periodontal referral patterns. Thus, the purpose of this study was to examine the differences in periodontal referral patterns in the same offices separated by a 20-year interval (i.e., 1980 and 2000). METHODS: A retrospective chart analysis was conducted on a total of 782 patient charts from three conveniently selected periodontal practices. Charts were randomly selected from two time periods: 1980-1981 and 2000-2001. The following information was obtained from each patient record: gender, age at time of initial examination, tobacco smoking status at time of initial examination, periodontal case type, number of missing teeth at initial examination (not including third molars), and number of teeth scheduled for extraction per periodontal treatment plan. Descriptive data were analyzed using frequency distributions, measures of central tendency, and measures of dispersion. Non-parametric statistics were used to examine the relationship of disease severity as a function of site, time period, and patient age. RESULTS: The following trends were noted: 1) an increase in the average age of patients at the time of the initial examination; 2) a decrease in the percentage of patients using tobacco at the time of the initial interview; 3) an increase in the percentage of periodontal Case Type IV patients with a concomitant decrease in the number of periodontal Case Type II patients; 4) an increase in the average number of missing teeth per patient at the initial examination; and 5) an increase in the average number of teeth scheduled for extraction per periodontal treatment plan. CONCLUSIONS: Characteristics of patients referred in 1980 compared to those referred in the year 2000 indicate that, although fewer patients used tobacco, there were several noteworthy trends. At referral, patients exhibited a greater loss of teeth, had more severe disease, and required extraction of a greater number of teeth in 2000 compared to 1980. Possible reasons for these trends are discussed.

Adult↗
PubMed2003

Early functional loading at 5 days for Brånemark implants placed into edentulous mandibles: a prospective, open-ended, longitudinal study.

BACKGROUND: Traditionally, implants placed in the mandible heal for 3 to 4 months before they are loaded. In maxillae, healing time usually takes 5 to 6 months. The purpose of this study was to evaluate placement of 4 to 6 implants in edentulous mandibles. The implants were placed between mental foramina for support of non-metal, reinforced, fixed, implant-supported provisional prostheses. A unique method was used to convert existing dentures into fixed, implant-supported appliances. The implants were functionally loaded early (5 days). METHODS: Twenty patients with edentulous mandibles or with 2 to 3 remaining mandibular teeth were enrolled in this open-ended, prospective study. Existing dentures without porcelain teeth were modified for use as a surgical guide. These dentures were used as temporary fixed prostheses. Patients were to have metal-reinforced appliances fabricated by the referring dentists after 3 to 4 months of healing. After implant installation, prosthetic abutments were fixed to the implants and tightened to 20 Ncm without counter torque. Bone quality and quantity as well as implant size and position were entered into a computer database. Impression copings were attached to the abutments, and the modified denture was used for a pick-up impression. After the impression was made, implant replicas were fitted to the impression copings and casts were poured. Gold cylinders were processed into the tissue side of the denture. Laboratory screws were used to attach the denture with gold cylinders to abutment replicas. The dentures were processed, polished, and inserted 5 days after implant surgery. Radiographs were taken to verify proper fit of the gold cylinders to the prosthetic abutments (baseline). Radiographs were taken at each follow-up visit and were used to measure changes in crestal bone levels. RESULTS: Twenty patients received 92 machined-surface commercially pure titanium implants in fully edentulous mandibles. Of the total number of implants placed, two were lost between 0 to 1 year and one between 1 to 2 years. Twenty patients with a total of 90 implants were followed between 0 to 1 year. Fourteen patients have been followed between 1 to 2 years, 7 between 2 to 3 years, and 2 between 3 to 4 years. One patient died after 9 months of loading (4 implants loaded, 2 sleeper implants); another died between 1 to 2 years. A total of 6 implants remained buried (sleepers). At 2 years, the cumulative success rate is 96.3%. Survival of the implant bridges is 100.00%. The mean crestal bone level at 5 days for 11 patients was 2.1 mm (SD 0.526, SE mean 0.159) (measurements were not available for the deceased patient), while the mean level at an average of 15 months was 1.96 mm (SD 0.585, SE mean 0.176). Differences between the measurements taken at 5 days with those taken at an average of 15 months were not significant (P < 0.683). CONCLUSIONS: Results of this study indicate that 4 to 5 implants can be placed and loaded within 5 days of implant insertion with high success (96.3%). Success rates for the interim and final prosthesis are 100%. A simple, possibly cost-effective method of using non-metal reinforced dentures as interim fixed, provisional dentures has been described. Impressions and registrations for making the prosthesis can be made at the time of implant installation, and this method is accurate enough to make provisional restorations. The modified denture can function as an interim fixed, implant-supported prosthesis for up to 30 months. Results of x-ray measurements indicate stable crestal bone levels for up to an average of 15 months.

Aged↗
PubMed2002

Clinical and histologic findings for microimplants placed in one stage and loaded for three months: a case report.

BACKGROUND: Implants are placed in either one or two stages. There is an absence of histologic human evidence relating to implant integration after loading. PURPOSE: The purpose of this case report was to present clinical and histologic findings for smooth-surfaced titanium turned microimplants placed in one stage and loaded after healing. MATERIALS AND METHODS: Five one-piece microimplants were placed in a fully edentulous mandible. Three microimplants (tests) were placed in one stage and extended through the keratinized mucosa for 3 mm. Two additional microimplants (controls) were placed even with the mucosa. After 3 months of healing, three test implants were loaded for an additional 3 months. At this time, three loaded implants and one control were removed en bloc. RESULTS: Histologic and histometric evaluations were made. For all specimens, there was excellent bone-to-implant contact. The loaded implants had from two to four exposed threads. Using marginal bone levels as the reference, the highest percentage of bone-to-implant contact was noted with the unloaded control implant (92.2%). One nonaxially loaded implant had 66.9% bone-to-implant contact, whereas the axially loaded implants (n = 2) had 77.8% bone-to-implant contact. CONCLUSIONS: Within the limits of this case report, smooth-surfaced, titanium threaded microimplants placed in one stage and loaded for 3 months demonstrated excellent osseointegration, with varying bone-to-implant contact. The amount of bone-to-implant contact may be related to axial implant loading.

Bone Remodeling↗
PubMed2002

Effect of barrier membranes and autologous bone grafts on ridge width preservation around implants.

BACKGROUND: The purpose of this study was to explore the effect of barrier membranes and autologous bone grafts on the preservation of ridge width around implants. MATERIALS AND METHODS: Sixty-one patients were chosen from a database of case series; treatment assignment was based on clinical judgment. The patients received a total of 76 implants: 34 implants with guided tissue regeneration procedures, 27 with autologous bone grafts, and 15 without ridge preservation procedures (control group). RESULTS: The ridge width around the 76 implants decreased an average of 1.4 mm (95% CI, -1.9 to -1.1 mm). Implants placed with autologous bone grafts or membranes tended to have worse outcomes. When compared to the no augmentation group, implants placed with guided tissue regeneration and autologous bone grafts resulted in 0.1 mm of additional bone loss (95% CI, -1.7 to -1.5 mm; p < .93) and 0.8 mm of additional bone loss (95% CI, -2.3 to 0.7 mm; p < .28), respectively. CONCLUSIONS: Autologous graft procedures or barrier membranes do not appear to improve crestal ridge preservation around implants.

Aged↗
PubMed2001

Editorial: Dedicated to the Memory of Marshall R. Urist.

BACKGROUND: Previous experimental studies have shown a higher degree of bone-implant contact for surface-enlarged implants compared with machined implants. Yet, there is insufficient evidence that such implants show higher stability and an increased survival rate. PURPOSE: The purpose of this investigation was to study the integration and stability of grit-blasted implants with retention elements on the implant neck, with and without marginal bone defects, compared with machined implants without retention elements. MATERIALS AND METHODS: After tooth extraction of the mandibular premolars in six dogs, two grit-blasted, partly microthreaded Astra Tech implants and one standard Brånemark implant were bilaterally placed in each dog. On one side, 3 yen 3 mm large buccal defects were created, to expose three to four implant threads. The contralateral side served as control, and no defects were made. The animals were sacrificed after 4 months of healing. Implant stability was measured using resonance frequency analysis at implant installation and after 4 months of healing. Histologic and histomorphometric evaluation was made after 4 months of healing. RESULTS: Resonance frequency analysis indicated that all implants in the test and control groups were osseointegrated after 4 months, with a tendency toward higher implant stability for the Astra Tech implants. There was a statistically significant higher increase in resonance frequency for the Astra test implants compared with their corresponding controls. Histology and histomorphometry showed well-integrated implants with varying degrees of bone repair at the defect sites. The greater bone-implant contact for the Astra implants was statistically significant. No significant difference between the implants in amount of bone filling the threads was recorded. CONCLUSIONS: The Astra Tech implants tested showed a higher degree of bone-implant contact and higher level of bone regenerated at defect sites compared with the Brånemark implants. Resonance frequency analysis demonstrated a significantly higher increase in the Astra test implants compared with their control groups than did the Brånemark test implants versus their controls.

Journal Article↗
PubMed2001

Editorial.

Explore the source record for details and available documents.

Journal Article↗