A multi-center study comparing dual acid-etched and machined-surfaced implants in various bone qualities.

BACKGROUND: A major reason for the success of modern dental implant systems has been the development of implant designs that enhance direct bone-implant interface. Surface roughness has been a factor in this success and different systems have utilized very different implant surface roughness. The major purpose of this study was to evaluate 2 similar implants with different surface roughness characteristics. METHODS: Two similarly designed, screw-type, commercially pure titanium implants, one dual acid-etched (DAE) and the other machined-surfaced (MS), were compared in this prospective, randomized-controlled, multi-center study, in which a total of 97 patients were enrolled at a private dental practice or a university dental clinic. Both implant types were placed in each patient using a 2-stage approach with a conventional 4- to 6-month healing period. Implants supported fixed prostheses, hybrid prostheses, and overdentures as dictated by the individual patient's need. All of the cases were followed using clinical and radiographic examinations. Criteria of success were the absence of peri-implant radiolucency, mobility, and persistent signs or symptoms of pain or infection. RESULTS: Of the 432 implants (247 dual acid-etched, 185 machined-surfaced), 36 implants (12 dual acid-etched and 24 machined-surfaced) have failed. The pre-loading integration success rate of the dual acid-etched implants (95.0%) was statistically higher (P < 0.01) than the success rate of the machined-surfaced implants (86.7%). At 36 months, the cumulative success rates (CSR) are 95.0% for the dual acid-etched implants and 86.7% for the machined-surfaced implants. CONCLUSIONS: The difference in success rates is most likely attributed to the acid-etched surface characteristics. The greatest performance difference is observed in the conditions of poor quality or soft bone where the 3-year post-loading CSR are 96.8% (dual acid-etched) and 84.8% (machined-surfaced).

The effect of locally delivered controlled-release doxycycline or scaling and root planing on periodontal maintenance patients over 9 months.

BACKGROUND: This research report evaluates clinical changes resulting from local delivery of doxycycline hyclate (DH) or traditional scaling and root planing (SRP) in a group of patients undergoing supportive periodontal therapy (SPT). METHODS: In all, 141 patients received either DH (67) or SRP (74) treatment in sites > or =5 mm on one-half of their dentition at baseline and month 4. RESULTS: Clinical results were determined at month 9. Baseline mean probing depth recordings were similar between the two groups (DH = 5.9 mm; SRP = 5.9 mm). Mean month 9 results showed similar clinical results for attachment level gain (DH 0.7 mm; SRP 0.8 mm) and probing depth reduction (DH 1.3 mm; SRP 1.1 mm). Percentage of sites showing > or =2 mm attachment level gain at month 9 was 24.7% in the DH group and 21.2% in the SRP group. Thirty-nine percent (39%) of DH sites and 38% of SRP sites showed > or =2 mm probing depth reduction. When treated sides of the dentition were compared to untreated sides, DH showed a difference in disease activity (> or =2 mm attachment loss) from 19.3% (untreated) to 7.2% (treated); and SRP from 14.3% (untreated) to 8.1% (treated). CONCLUSIONS: Results show that both DH without concomitant mechanical instrumentation and SRP were equally effective as SPT in this patient group over the 9-month study period.

Older workers' progression from private disability benefits to Social Security disability benefits.

People with medical conditions that limit their ability to work tend to receive short-term disability benefits initially and may then move to long-term and eventually to permanent disability benefits. The progression of older workers (those aged 55 to 64) along that continuum of benefits is documented here with data from a large disability insurance company. The data show that older workers who receive short-term medical disability benefits are three times as likely as younger workers to progress to receipt of Social Security Disability Insurance (SSDI) benefits, although a slight reversal of that trend occurs as workers pass age 62. Musculoskeletal conditions are the most frequent basis of short-term disability claims among older workers, with circulatory conditions running a close second. Furthermore, although all medical conditions are more likely to lead to SSDI benefits among older workers, circulatory conditions do so most frequently. This article discusses industry standards for the management of disability claims at each level of severity. It also addresses common and emerging disability management practices that may reduce the likelihood of impaired workers developing long-term or permanent financial dependence on disability benefits programs.

Two multi-center studies evaluating locally delivered doxycycline hyclate, placebo control, oral hygiene, and scaling and root planing in the treatment of periodontitis.

BACKGROUND: The clinical efficacy and safety of doxycycline hyclate (8.5% w/w) delivered subgingivally in a biodegradable polymer (DH) was compared to placebo control (VC), oral hygiene (OH), and scaling and root planing (SRP) in 2 multi-center studies. METHODS: Each study entered 411 patients who demonstrated moderate to severe periodontitis. Patients had 2 or more quadrants each with a minimum of 4 qualifying pockets > or =5 mm that bled on probing. At least 2 of the pockets were > or =7 mm. Treatment with DH, VC, OH, or SRP was provided at baseline and again at month 4. Clinical parameters were recorded monthly. RESULTS: DH and SRP resulted in nearly identical clinical changes over time in both studies. Mean 9 month clinical attachment level gain (ALG) was 0.8 mm for the DH group and 0.7 mm for the SRP group in Study 1, and 0.8 mm (DH) and 0.9 mm (SRP) in Study 2. Mean probing depth (PD) reduction was 1.1 mm for the DH group and 0.9 mm for the SRP group in Study 1 and 1.3 mm for both groups in Study 2. Frequency distributions showed an ALG > or =2 mm in 29% of DH sites versus 27% of SRP sites in Study 1 and 31% of DH sites versus 34% of SRP sites in Study 2. PD reductions > or =2 mm were seen in 32% of DH sites versus 31% of SRP sites in Study 1 and 41% of DH sites versus 43% of SRP sites in Study 2. Comparisons between DH, VC, and OH treatment groups showed DH treatment to be statistically superior to VC and OH. Safety data demonstrated a benign safety profile with use of the DH product. CONCLUSIONS: Results of this trial demonstrate that treatment of periodontitis with subgingivally delivered doxycycline in a biodegradable polymer is equally effective as scaling and root planing and superior in effect to placebo control and oral hygiene in reducing the clinical signs of adult periodontitis over a 9-month period. This represents positive changes resulting from the use of subgingivally applied doxycycline as scaling and root planing was not limited regarding time of the procedure or use of local anesthesia.

Periodontal trauma and mobility. Diagnosis and treatment planning.

With the dearth of well-controlled human clinical studies, it is still impossible to answer the question of whether occlusal trauma modifies the progression of attachment loss resulting from inflammatory periodontal disease and the companion questions related to the treatment of occlusal trauma and mobility. Teeth with stable mobility are apparently at no greater risk of attachment loss than nonmobile teeth. Increasing mobility is a concern that must be addressed by inflammatory control, occlusal adjustment, and perhaps some type of stabilization or splinting of the tooth in question. In addition, greater attachment gains have been noted when occlusal adjustment was included as part of surgical therapy. There is no question that aspects of occlusal therapy have an empiric base. It is incumbent on the clinician to examine for, diagnose, and treat trauma from occlusion to stabilize the dentition. Proper occlusal management assists in maintaining the patient's natural dentition in a state of health and comfortable function.

Serologic reactions of oral gram negative anaerobic bacilli.

Serological reactions were performed using hyperimmune rabbit antisera and antigenic preparations of Leptotrichia buccalis, Fusobacterium fusiforme, and Fusobacterium polymorphum. All tests indicated that there was serologic cross reactivity between the two Fusobacterium species. No cross reactivity could be detected between the Fusobacterium species and L. buccalis. The findings suggest that F. fusiform and F. polymorphum are similar in their immunogenicity, and that the grouping of these two organisms as F. nucleatum may be justified.

Leptotrichia buccalis hemagglutination in cell binding and salivary inhibition studies.

The characteristic hemagglutination (HA) of Leptotrichia buccalis was used for measuring its attachment to various human cells and for determining if saliva contained hemagglutination inhibition (HI) factors. The microbial strain utilized displayed the characteristic EM morphology of L. buccalis. Sonicated preparations of the organism were tested for HA activity before and after adsorption with human cells. Buccal epithelial cells, red blood cells (RBC), HeLa and embryonic kidney cells all bound the HA fragments of the organisms. The bacterial fragments on the cells could be observed by fluorescent antibody testing. The fragments were released from the cells used for adsorption with chelators and upon addition of CaCl2 the HA activity returned. Whole saliva displayed hemagglutination inhibition activity in a manner suggesting a binding site interaction. The similarity of the HA activity of F. nucleatum is discussed as are the relationships of cell binding to colonization of the organisms and immunopathology to host cells.

Anticomplementary activity of Fusobacterium polymorphum in normal and C4-deficient sources of guinea pig complement.

Fusobacterium polymorphum has been isolated from the gingival crevice in humans and has been implicated in the immunopathology of periodontal diseases. The presence of alternative complement pathway factors in gingival crevice material suggests the contribution of this process in the manifestation of the local host response. A complement consumption assay was used to show that the anticomplementary activity of a cell-wall preparation from F. polymorphum in guinea pig complement progressed optimally at 37 degrees C and suboptimally at 0 degrees C. Similar levels of complement consumption were recorded at both temperatures, but a higher concentration of cell walls was required to demonstrate maximum activity in the cold. Augmentation experiments with additional normal and heat-treated complement showed the presence of heat-labile factors that controlled and limited the consumption of complement to a constant proportion of the total amount present. These same experiments indicated that there were no reactive antibodies in the complement used in the assay. Similar tests with C4-deficient guinea pig sera confirmed that F. polymorphum cell walls were capable of generating alternative complement pathway activity in guinea pig sera.

Hemagglutinating activity of Fusobacterium nucleatum.

Gingival isolates of oral Fusobacterium nucleatum strains (gram-negative anaerobic fusiform bacilli) have shown the characteristic ability to hemagglutinate a variety of erythrocytes (RBC) of human and animal origin. Other members of the genus tested (F. necrophorus, F. varium, and F. mortiferum) displayed little if any ability to hemagglutinate RBC. The hemagglutination (HA) activity could be observed in the F. nucleatum strains with the whole cells and in most instances with sonicated preparations of the organisms. The HA activity was observed in cell wall preparations of the organism and appeared dependent upon a heat-labile protein component of the cell wall. In decreasing order, the RBC that would hemagglutinate with the smallest concentration of HA preparations were rabbit, monkey, human, sheep, horse, and ox. No differences in HA activity of the preparations with cells from the various human blood types were noted. Absorption of the HA preparation of one strain with human cells removed HA moiety was bound to the cells via a Ca2+ binding site interaction since ethylenediaminetetraacetic acid and ethylene glycol-bis-N,N'-tetraacetic acid inhibited binding, and HA could be reestablished by the addition of Ca2+ but not Mg2+. Rabbit antisera to the F. nucleatum strains inhibited HA activity when tested with the HA preparation in the standard test, whereas anti-Leptotrichia buccalis sera or normal rabbit sera had no effect. A tanned-cell passive HA test with rabbit anti-F. nucleatum sera displayed reactivity between the homologous strains but little reactivity with the other Fusobacterium species tested.

A histologic examination of a free osseous autograft. Case report.

Twenty-eight months following free osseous autograft therapy, a block section was taken for histologic examination. (2) Microscopically, the periodontal structures were reconstructed with new alveolar bone, periodontal ligament, and cementum. (3) A 'separation artifact' was present between new and old cementum. This defect is probably an artifact of histologic processing.

An investigation of the clinical and histologic effects of selected dentifrices on human palatal mucosa.

A study was undertaken in 24 human volunteer subjects to determine the possible effects of selected commercially available dentifrices on clinically normal masticatory mucosa. An acrylic stent was fabricated which was designed to hold four test dentifrices in close apposition to the palatal tissues for 1 hour. Evaluation approximately 8 hours later revealed pathologic responses which were evident clinically and histologically. 1. Clinically, palatal tissues exposed to Crest were not distinguishable from control areas, while Colgate (mfp), MacCleans, and Ultra Brite produced erythematous changes which were statistically significant when compared with adjacent control sites. 2. Histologically, epithelial changes were seen within the test sites which ranged from a parakeratin-like surface layer to necrosis and intraepithelial abcess formation. Control sites consisted of normal orthokeratinized palatal mucosa in all cases. 3. The more severe microscopic reactions were noted with MacCleans and Ultra Brite, while the milder reactions were associated with Colgate (MFP). Crest infrequently produced a parakeratin-like response. The response was not statistically significant when compared with controls. 4. The clinical and histologic reactions were generalized throughout the test population, suggesting that the responses were not due to individual hypersensitivity but due to irritation from one or more of the dentifrice components. Although the clinical significance of these findings could not be readily assessed, the potential for irritation of human palatal mucosa by selected dentifrices has been demonstrated. These findings support the suggestion by the World Workshop in Periodontics (1966)20 that efforts should be directed to the development of dentifrice materials less harsh to the oral tissues.