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PubMedDate not supplied

Anterior esthetic fixed appliances for the preschooler: considerations and a technique for placement.

One of the pediatric dentist's greatest restorative challenges is the esthetic rehabilitation of a young toddler who has suffered multiple tooth loss subsequent to rampant early childhood caries or extensive dental trauma. An anterior esthetic appliance may be used to replace lost teeth. The most decisive factor for placing an anterior esthetic appliance is parental desire. Other considerations include: space maintenance, masticatory function, speech development, and tongue habits. However, there is no strong evidence that early loss of maxillary incisors will have any significant, long lasting effect on the growth and development of the child. This paper discusses in detail one type of fixed anterior esthetic appliance and the considerations to be made when deciding when and why to place them.

Child, Preschool↗
PubMed2002

Use of bone grafts for the enhancement of a GTR-based root coverage procedure: a pilot case study.

The use of guided tissue regeneration (GTR) procedures for the treatment of gingival recession has shown encouraging results and is gaining clinical acceptance. However, attaining space maintenance beneath the membrane remains a problem for clinicians. Hence, the purpose of this pilot case study was to evaluate the effect of adjunctive demineralized freeze-dried bone allograft (DFDBA) placement during collagen membrane GTR-based root coverage procedures. Five patients with Miller Class I or II defects were treated with a combination of DFDBA and collagen membrane. Clinical parameters monitored include recession depth, probing attachment level, probing depth, width of keratinized gingiva, and recession width. Measurements were taken at baseline and 6 months. A statistically significant reduction in recession depth (3.1 +/- 0.7 mm) was observed at 6 months, representing 93.4% total attainable root coverage. A significant reduction of recession width (3.5 +/- 1.2 mm) after 6 months was also noted. Clinically, a statistically significant mean gain of 3.3 +/- 0.6 mm in clinical attachment and 0.8 +/- 0.9 mm in keratinized gingiva were obtained at 6 months. No statistically significant difference was found in probing depth between baseline and 6 months postoperative. Plaque and gingival indices remained low and showed no statistically significant change throughout the study period. Results from this pilot case study indicate that use of DFDBA during collagen membrane GTR-based root coverage could be beneficial.

Adult↗
PubMed2000

Trapezial resection arthroplasty for osteoarthritis: use of abductor pollicis longus tendoplasty with interpositional material.

In this series, 45 patients had 54 trapezial resection arthroplasties for carpometacarpal osteoarthritis, with nine of the patients having bilateral arthroplasties. A major slip of the abductor pollicis longus tendon was used as a sling, with the underlying flexor carpi radialis tendon as stabilizer. Palmaris longus tendon, when present (42 cases), and absorbable gelatin sponge, when palmaris was absent (12 cases), served as interpositional material. Review was done an average of 4.3 years (range, 1 to 11 years) after the procedure. The average space maintenance of resection site was 4.4 mm. This decreased to an average of 3.5 mm on the key pinch stress maneuver. Subjectively, the patients judged their results to be good to excellent in 49 instances (91%) and fair in 5 (9%).

Adult↗
PubMed2001

The clinical study of Healon 5 in phacoemulsification and IOL implantation.

PURPOSE: To compare a new ophthalmic viscoelastic device (OVD) Healon 5 with two other kinds of OVDs commonly used in China during phacoemulsification and intraocular lens (IOL) implantation in terms of removal time, intraocular pressure, corneal and anterior chamber response. METHODS: This prospective randomized study, in which patients and observers are masked, comprises niety eyes. They were randomly divided into 3 groups with different OVDs. Healon 5 (sodium hyaluronate 5,000 2.3%) was compared with Healon GV (sodium hyaluronate 7,000 1.4%) and Iviz (sodium hyaluronate 1.0%). The surgeries were performed with temporal corneal incision, phacoemulsification in situ and foldable lens intracapsular implantation. The characteristic and the removal time of the viscoelastic material as well as the postoperative IOP, corneal reaction and anterior chamber reactions of the eyes were observed preoperatively and 24 hrs postoperatively. Exclusion criteria were glaucoma, a preoperative dilated pupil diameter smaller than 5.0 mm, proliferative diabetic retinopathy, significant corneal pathology or a history of uveitis. RESULTS: The removal time was 47.42 +/- 13.09 seconds in Healon 5, 16.50 +/- 5.45 in Healon GV and 15.83 +/- 7.40 in Iviz. The removal time of Healon 5 group was significantly longer than that of the other groups (P = 0.000). There is no significant IOP change 24 hours postoperatively and the difference of intraocular pressure among three groups was not significant (P > 0.05). Healon 5 group had the slightest corneal and anterior chamber response, followed by Healon GV and Iviz. CONCLUSION: Although takes longer time to remove, Healon 5 is an ideal viscoelastic material for its superior space maintenance capacity and high dispersity which provides superior protection of endothelial cells compared to Healon GV and Iviz.

Anterior Chamber↗
PubMedDate not supplied

A retrospective radiographic evaluation of primary molar pulpectomies.

Relatively few long-term studies have been performed to evaluate the clinical success of one-appointment pulpectomies in primary molar teeth. The purpose of this retrospective study was to evaluate the radiographic appearance of nonvital primary molars before and after treatment with a one-appointment formocresol pulpectomy technique. The mean length of time since pulpectomy treatment for the 62 primary molars was 40.2 months. Based upon strict radiographic criteria, the one-appointment pulpectomy procedure was considered to be successful in 82.3% (51) of the cases, with 3.2% (2) of pulpectomized primary molars needing retreatment, and 14.5% (9) of pulpectomy procedures failing. The pulpectomy procedure is indicated when inflammation of the pulpal tissue extends into the root canals, and possibly involves the periapical and/or bifurcation areas. This procedure provides an alternative to extraction and space maintenance when the pediatric dentist encounters a nonvital primary molar tooth.

Child, Preschool↗
PubMed1989

[Changes on pronunciation using the removal appliance for children with early loss of deciduous teeth. Comparison between good occlusion children with missing anterior-posterior deciduous teeth].

The purpose of this study was to examine missing anterior teeth and posterior teeth for possible differences according to the where the teeth were missing site, a comparison was made between children with such defects and those with relatively good occlusion. The following results were obtained: 1. Compared with children with missing anterior teeth, children with missing posterior teeth showed more differences in the frequency range for vowel formants from those with relatively good occlusion. 2. As for vowel formant, missing anterior teeth and missing posterior teeth presented more such differences for formant i and formants i and e, respectively. 3. For each formant, more such differences were noted for the first formant and the third formant compared with comparatively fewer such differences noted for the second formant. 4. In terms of the strength of voice components in each frequency range, consonant pronunciation rather than vowel pronunciation proved to be influenced by missing either anterior or posterior teeth. 5. For vowel pronunciation, more such differences were noted at low to intermediate frequency ranges. 6. Pronunciation of words containing the letter t and k tended to be improved for missing anterior and posterior teeth, respectively, but pronunciation proved to be improved in a difficult manner. The above results revealed that compared with missing anterior teeth, missing posterior teeth presented more differences from children with relatively good occlusion, suggesting that not only space maintenance and masticatory function but also speech function must be considered in preparing the removal appliance for missing posterior teeth of children.

Articulation Disorders↗
PubMed1989

Light and electron microscopic study of hamster cheek pouch treated with 9,10 dimethyl 1,2 benzanthracene and retinoic acid.

The present study reports light and electron microscopic observations of hamster cheek pouch epithelium exposed to 25 micrograms DMBA (DMBA = 9,10 Dimethyl, 1,2 Benz(a)-nthracene, RA = Retinoic Acid) and 25 micrograms DMBA along with 25 micrograms, 50 micrograms and 100 micrograms retinoic acid. Significant delay in tumour induction was observed in the animals treated with DMBA + retinoic acid. DMBA + retinoic acid treated cheek pouch developed papillary epidermoid carcinomas which were less invasive and less keratinized than only DMBA treated animals. At cellular level DMBA treated animals showed keratinized cells with thick bundles of tonofilaments, broken basement membrane, wide intercellular spaces and loss of desmosomal attachments, whereas animals treated with DMBA + retinoic acid showed decrease in the intercellular spaces, maintenance of basement membrane and intracellular organelles with suppression of keratinization, indicating the differentiating effect of retinoic acid on DMBA transformed cells of hamster cheek pouch.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1995

Guided bone regeneration of bone defects associated with implants: an evidence-based outcome assessment.

Guided bone regeneration is a new technique that evolved following the guided tissue regeneration procedure for regeneration of lost periodontium. The objective of guided bone regeneration is to promote bone formation in osseous deformities either before or in conjunction with endosseous implant placement. Osseous defects consist mainly of extraction sites, dehiscences or fenestrations, and localized ridge deformities. In addition, bone defects may either provide natural spacemaking or be nonspacemaking. A plethora of publications indicate that the guided bone regeneration technique can be used successfully in all types of defects. Nonspacemaking defects usually require bone graft materials to assist in space maintenance and enhance bone formation. Fixation pins are also used, either with or without graft materials, in this regard. The scientific literature on guided bone regeneration was reviewed by a task force to determine techniques proven to increase predictability relative to successful patient outcomes and to develop specific evidence based diagnostic and treatment decision trees.

Alveolar Bone Loss↗
PubMed1995

Bone formation following guided tissue regeneration (GTR).

The principle of guided tissue regeneration using barrier membranes has become an accepted method for the treatment of teeth with severe osseous defects and furcation involvement. A technique was developed using an expanded polytetrafluoroethylene soft-tissue patch, 1 mm thick (W.L. Core and Assoc., Flagstaff, AZ), in conjunction with an alloplast hydroxyapatite bone substitute (HA-500, 40-60 mesh) (Orthomatrix, Minneapolis, MN), for space maintenance in severe osseous defects. A case report is presented which demonstrates the successful use of this method, and includes a fourth-year re-entry procedure that illustrates the complete bone fill and obturation of a severe vertical defect and Class II furcation of a mandibular first molar.

Aged↗
PubMedDate not supplied

Vertical ridge augmentation using polylactic membranes in conjunction with immediate implants in periodontally compromised extraction sites: an experimental study in dogs.

Polylactic membranes were evaluated for vertical ridge augmentation around immediate implants in periodontally compromised extraction sites. Ligature-induced periodontitis was produced in 10 adult beagle dogs. The periodontium was allowed to heal for 6 weeks. All premolar teeth were extracted and three implants were placed immediately into the extraction sockets on either side of the mandible so that the polished cone extended above the alveolar bone level. On one side of the mandible, the implants were covered with a 0.2-mm-thick polylactic membrane (DL-lactide-co-trimethylene carbonate in a ratio of 7:3). Histologic and morphometric analyses performed after 3 and 5 months revealed that the membrane group did not exhibit significantly greater bone-implant contact than the controls. The occurrence of dehiscences correlated significantly with use of the membrane. Use of the membrane was associated with significantly less peri-implant bone height after 5 months. No remnants of the membrane material could be identified after 3 or 5 months, indicating rapid resorption during the first weeks of implantation. The tested membrane material did not fulfill the requirements of resorption kinetics and space maintenance for guided bone regeneration in vertical ridge augmentation.

Alveolar Process↗
PubMed1991

A health maintenance facility for space station freedom.

We describe a health care facility to be built and used on an orbiting space station in low Earth orbit. This facility, called the health maintenance facility, is based on and modeled after isolated terrestrial medical facilities. It will provide a phased approach to health care for the crews of Space Station Freedom. This paper presents the capabilities of the health maintenance facility. As Freedom is constructed over the next decade there will be an increase in activities, both construction and scientific. The health maintenance facility will evolve with this process until it is a mature, complete, stand-alone health care facility that establishes a foundation to support interplanetary travel. As our experience in space continues to grow so will the commitment to providing health care.

Ambulatory Care Facilities↗
PubMed1984

Skin glands in the axolotl: the creation and maintenance of a spacing pattern.

The morphogenesis of skin glands in the larval axolotl is described at the light microscope level. The glands are derived from the epidermis, but are eventually located in the dermis. The glands are non-randomly arranged within the skin and the spacing pattern tends towards a hexagonal array in two dimensions. Analysis of the spacing pattern in animals of different sizes reveals that a clear relationship exists between gland size and the distance between glands. Occasionally, new small glands are inserted into the pattern, suggesting that the spacing of glands in under a dynamic control throughout the growth of the axolotl. The possible mechanisms underlying the creation and maintenance of the pattern are discussed.

Ambystoma↗
PubMed2006

Mutation accumulation in space and the maintenance of sexual reproduction.

The maintenance of sexual reproduction remains one of the major puzzles of evolutionary biology, since, all else being equal, an asexual mutant should have a twofold fitness advantage over the sexual wildtype. Most theories suggest that sex helps either to purge deleterious mutations, or to adapt to changing environments. Both mechanisms have their limitations if they act in isolation because they require either high genomic mutation rates or very virulent pathogens, and it is therefore often thought that they must act together to maintain sex. Typically, however, these theories have in common that they are not based on spatial processes. Here, we show that local dispersal and local competition can explain the maintenance of sexual reproduction as a means of purging deleterious mutations. Using a spatially explicit individual-based model, we find that even with reasonably low genomic mutation rates and large total population sizes, asexual clones cannot invade a sexual population. Our results demonstrate how spatial processes affect mutation accumulation such that it can fully erode the twofold benefit of asexuality faster than an asexual clone can take over a sexual population. Thus, the cost of sex is generally overestimated in models that ignore the effects of space on mutation accumulation.

Adaptation, Physiological↗
PubMed1976

A preloaded radium needle implant device for maintenance of needle spacing.

A small stainless steel bar was machined to accept radium needles. The stainless steel bar will hold a rack of two, three, four, or five radium needles in a single plane. The crossing needle may be affixed to the bar so that textbook-like geometry is possible. The stainless steel bar remains in place during the entire implant. Spacing between needles is close to perfect. The time required to insers the implant is reduced compared to free-hand insertions, and less variation in dose is seen on computer-assisted calculations. Two years' experience in the use and development of the radium needle holder will be reviewed.

Head and Neck Neoplasms↗
PubMed2005

Maintenance of interbody space in one- and two-level anterior cervical interbody fusion: comparison of the effectiveness of autograft, allograft, and cage.

UNLABELLED: The use of allografts, autologous iliac crest grafts, and cages for anterior cervical fusion is well documented, however there is no comparison regarding the effectiveness of maintaining the interbody space with the three approaches. We retrospectively measured the rate and amount of interspace collapse, segmental sagittal angulations, clinical results, and radiographic fusion success rates to determine which is the best fusion material. We assessed 73 patients who had one- and two-level cervical discectomies and interbody fusions without instrumentation. The three groups had similar clinical results and fusion rates. However, in the autograft group union occurred in 4 months. In the allograft group, union did not occur until 5.54 months. Moreover, the loss of cervical lordosis (2.75 degrees) was less in the cage group than in the allograft group (9.23 degrees). Additionally, the anterior interspace collapse (1.73 mm) in the cage group was less than the collapse recorded in the autograft group (2.82 mm) and in the allograft group (4 mm). An interspace collapse of 3 mm or greater was observed in 56.1% of the patients in the allograft group, compared with only 19% of the patients in the cage group. We showed that the cage is superior to the allograft and autograft in maintaining cervical interspace height and cervical lordosis after one-level and two-level anterior cervical decompression procedures. LEVEL OF EVIDENCE: Therapeutic study, Level III-2 (retrospective cohort study).

Cervical Vertebrae↗