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At least 55 records · Page 3Linked to original sources
PubMed2005

Long-term outcome following treatment of multiple Miller class I and II recession defects in esthetic areas of the mouth.

BACKGROUND: Multiple recession defects can be successfully treated using envelope-type coronally advanced flaps. The aim of the present study was to evaluate the long-term (5 years) stability of clinical outcomes achieved with the surgery and the association between patient variables and long-term stability. METHODS: Seventy-three Miller Class I and II gingival recessions affecting 22 young, systemically healthy subjects were treated with coronally advanced flaps with no releasing incisions. All patients were instructed to perform a coronally directed roll technique to minimize the toothbrushing trauma to the gingival margin. The clinical reevaluation was made 1 year after the surgery. At this point, 13 patients took part in a supportive periodontal care program consisting of oral hygiene instructions, control of toothbrushing technique, and professional tooth cleaning every 4 months. The remaining nine patients did not participate and received only sporadic care by general dentists. At 5 years post-surgery, all patients were reexamined. RESULTS: At the 5-year examination, 94% of the root surfaces initially exposed due to gingival recession were still covered with soft tissue, and 85% of the treated recession defects showed complete coverage. Complete root coverage in all recessions was maintained in 15 out of 22 patients (68%). The long-term stability of the soft-tissue margin in the treated sites was significantly influenced by the patient's regular participation in the recall program and the susceptibility to gingival recession in other areas of the mouth. A statistically significant increase of keratinized tissue (0.80 +/- 0.64 mm) was observed between the 1- and 5-year observation visits, and the average increase of keratinized tissue between the baseline and the 5-year follow-up amounted to 1.38 +/- 0.90 mm. This increase was significantly affected by the baseline keratinized tissue (KT) and recession (REC) depth: in particular, the 5-year increase in the amount of keratinized tissue was greater in sites with a greater recession depth and lower amount of keratinized tissue at baseline. CONCLUSIONS: 1) The successful root coverage results obtained with the coronally advanced flap for multiple recession defects were well maintained over the 4-year observation period. 2) Negative patient characteristics such as a lack of compliance with a supportive care program and individual susceptibility to gingival recession were significantly associated with the recurrence in gingival recession. 3) The increase in keratinized tissue height that followed the coronally advanced flap procedure may be attributed to the tendency of the mucogingival line to regain its genetically determined position.

Adolescent↗
PubMed2003

Unilateral versus bilateral medial rectus recession.

BACKGROUND: Unilateral medial rectus recession is suitable for some cases of small-angle deviation in esotropia. This approach limits surgery to one eye, leaves other muscles untouched, and should be quicker than bilateral muscle surgery. This study compared the results of a range of medial rectus recessions, both unilateral and bilateral, performed by one surgeon. METHODS: Data were collected on all pediatric patients who had undergone medial rectus recession, unilateral and bilateral, performed by one surgeon between August 1, 1995, and March 31, 2002. Postoperative deviations were calculated from the short- (2 to 8 weeks) and long-term (6 to 48 months) follow-up visits. RESULTS: Medial rectus recessions were performed on 107 patients, 56 unilateral and 51 bilateral. After exclusions were made, 45 (80%) of the unilateral procedures and 41 (80%) of the bilateral cases were studied. At long-term follow-up, the mean prism diopter (PD) change in deviation per millimeter recessed (at distance) for unilateral recessions of 5 mm, 6 mm, 7 mm, and 8 mm were 2.3, 2.2, 2.3, and 2.5, respectively. For equivalent bilateral recessions the mean changes in deviation were 4.2, 4.0, 4.3, and 5.0 PD/mm. CONCLUSION: Unilateral medial rectus recession is a predictable method for surgical correction of small-angle pediatric esotropia. The change in deviation per millimeter of recession after unilateral recession is significantly less than that obtained from equivalent amounts of bilateral recession (P <.01).

Child↗
PubMed2005

Meniscal tears with fragments displaced in notch and recesses of knee: MR imaging with arthroscopic comparison.

PURPOSE: To retrospectively evaluate magnetic resonance (MR) imaging for the depiction of meniscal tears with partially detached meniscal fragments displaced in the intercondylar notch or in the meniscal recesses of the knee. MATERIALS AND METHODS: The institutional review board required neither its approval nor informed patient consent for the retrospective review of patient data; however, informed patient consent had been obtained before the MR imaging examinations were performed. The presence of meniscal tears with notch and recess fragments was determined at MR imaging and at subsequent arthroscopy in 101 consecutive knees to determine the value of MR imaging for the depiction of these lesions. Initial reports were reviewed to evaluate results of initial interpretations. MR images were retrospectively analyzed to determine the value of several MR image signs for the detection of displaced tears with notch or recess fragments. RESULTS: At arthroscopy, 37 (41%) of 91 torn menisci had partially detached fragments. Twenty-six torn menisci had notch fragments, and 14 had recess fragments; three torn menisci had one notch and one recess fragment each. At initial MR image analysis, 38 (36%) of 105 torn menisci had partially detached fragments. Twenty-eight torn menisci had notch fragments, and 13 had recess fragments; one torn meniscus had two recess fragments, and three torn menisci had one notch and one recess fragment each. At initial analysis, sensitivities and specificities were, respectively, 69% and 94% for detection of tears with notch fragments and 71% and 98% for detection of tears with recess fragments. At retrospective analysis of sagittal MR images, the presence of at least one sign indicative of meniscal tear with a notch fragment had sensitivities and specificities, respectively, of 65% and 78% for observer 1 and 77% and 73% for observer 2. The presence of at least one sign indicative of a meniscal tear with a recess fragment had sensitivities and specificities, respectively, of 64% and 77% for observer 1 and 64% and 76% for observer 2. CONCLUSION: Meniscal tears with notch and recess fragments are frequently seen at arthroscopy and can be depicted at knee MR imaging with moderate sensitivity and high specificity.

Adolescent↗
PubMed2003

Comparing thin-section and thick-section CT of pericardial sinuses and recesses.

OBJECTIVE: The aim of this study was to assess the prevalence and appearance of the pericardial sinuses and recesses on thin-section (2.5- or 3-mm) CT scans compared with thick-section (5- or 7-mm) CT scans. MATERIALS AND METHODS: Nine hundred forty-one consecutive contrast-enhanced chest CT scans were retrospectively evaluated. Three hundred sixty-five patients underwent thin-section CT, and 576 patients underwent thick-section CT. The prevalence and appearance of every pericardial recess were determined. RESULTS: Large recesses such as the superior aortic recess were depicted in 12.5-30.4% of patients using thick-section CT, whereas smaller recesses such as the postcaval recess were depicted in fewer than 5% of patients. With thin-section CT, the depiction rates increased significantly compared with thick-section CT (p < 0.01). Large recesses were depicted in 28.7-44.7% of patients, and smaller recesses were recognized in 10.8-19.8% of patients. Generally, most recesses were linear if they were small and became band-shaped as the fluid increased. However, the recesses were often visualized as crescent, triangle, spindle, ovoid, hemisphere, or irregular shapes. CONCLUSION: Pericardial sinuses and recesses are more frequently and better depicted on thin-section CT scans. Knowledge of their locations and shapes is helpful for distinguishing pericardial fluid from abnormal findings such as lymphadenopathy and cystic lesions.

Adolescent↗
PubMed2005

Locus heterogeneity in autosomal recessive congenital cataracts: linkage to 9q and germline HSF4 mutations.

Isolated (non-syndromic) congenital cataract may be inherited as an autosomal dominant, autosomal recessive, or X-linked recessive trait. Considerable progress has been made in identifying genes and loci for dominantly inherited cataract, but the molecular basis for autosomal recessive disease is less well defined. Hence we undertook genetic linkage studies in four consanguineous Pakistani families with non-syndromic autosomal recessive congenital cataracts. In two families linkage to a 38 cM region 9q13-q22 was detected. Although a locus for recessive congenital cataracts had not been mapped previously to this region, the target interval encompasses the candidate region autosomal recessive adult-onset pulverulent cataracts (CAAR). The CAAR was mapped previously to 9q13-q22, and may therefore be allelic to non-syndromic autosomal recessive congenital cataracts. The other two families did not demonstrate linkage to 9q, but both had a region of homozygosity at 16q22 containing the heat shock transcription factor 4 (HSF4) gene. The HSF4 mutations have been reported in four families with autosomal dominant cataracts and, recently, in a single kindred with autosomal recessive congenital cataract. Mutation analysis of HSF4 revealed homozygous mutations (p.Arg175Pro and c.595_599delGGGCC, respectively) in the two families. These findings confirm that mutations in HSF4 may result in both autosomal dominant and autosomal recessive congenital cataract, and highlight the locus heterogeneity in autosomal recessive congenital cataract.

Base Sequence↗
PubMed1986

The estimation of risks from the induction of recessive mutations after exposure to ionising radiation.

Since recent assessments of genetic risks from radiation have concentrated on harmful dominant effects, a quantitative assessment of risks from recessives is needed. Presumably, harmful recessives can arise at all loci coding for essential proteins (perhaps 10 000), but mutation to dominant alleles is likely to be a property of relatively few loci. While many recessives doubtless remain to be discovered, those known at present tend to have earlier and more severe effects than dominants. Induced recessive mutations can cause harm by partnership with a defective allele already established in the population; partnership with another recessive mutation induced at the same locus; the formation of homozygous descendants, that is, identity by descent; and heterozygous effects. Calculations based on a combination of data from observations on human populations and from mouse experiments suggest that an extra genetically significant dose of 1 cGy (centiGray, equivalent to 1 rad) X or gamma irradiation received by each parent in a stable population with a million liveborn offspring would induce up to 1200 extra recessive mutations. From partnership effects, about one extra case of recessive disease would be expected in the following 10 generations. Homozygosity resulting from identity by descent could not normally occur until the fourth generation after exposure but, on certain assumptions, about ten extra cases of recessive disease would be expected from this cause by the tenth generation. In the same period, about 250 recessive alleles would be eliminated in heterozygotes (that is, Muller's 'genetic deaths') given 2.5% heterozygous disadvantage. These deleterious heterozygous effects should not be combined with those of dominants, as has been done in some previous risk estimates. It is considered unlikely that many radiation induced recessives would show heterozygous advantage. Certain dominants (combined frequently at least 10(-3)) should be excluded from calculations of mutational risk because they are unlikely to be maintained by mutation.

Abnormalities, Radiation-Induced↗
PubMed1989

Occurrence of gingival recession in adults.

The occurrence of gingival recession was investigated in adults by age and gender and in relation to their dental status and frequency of toothbrushing. A total of 258 dentate subjects were clinically examined. Their mean age was 46 years and they had an average of 19.4 natural teeth. Gingival recession was recorded as present if any root surface was clearly visible without retraction of the gingival tissue. Recession was found on at least one tooth surface in 68% of subjects. Mean number of surfaces with recession was 7.2 for women and 10.4 for men. Subjects with gingival recession had fewer natural teeth than did those without recession. The two groups did not differ from each other in the number of filled teeth and decayed teeth. Mandibular teeth had more surfaces with recession than did maxillary ones. Sites of recession occurred quite symmetrically. Frequent toothbrushers had, both in the maxilla and mandible, more surfaces with recession than had those brushing their teeth infrequently. Frequent toothbrushing had a greater association with recession among women and in the youngest age group.

Adult↗
PubMed2003

Comparative clinical study of connective tissue graft and two types of bioabsorbable barriers in the treatment of localized gingival recessions.

BACKGROUND: Localized buccal recessions occur in more than 60% of individuals; therefore, there is a need for predictable root coverage techniques. The objective of the present study was to evaluate the clinical effectiveness of the guided tissue regeneration (GTR) procedure versus connective tissue graft (CTG) in the treatment of localized gingival recessions over a 12-month postoperative period. METHODS: Thirty bilateral matched pairs of localized buccal recessions in 22 patients were treated with CTG and GTR in this study. For the GTR procedure, two types of bioabsorbable barriers, polylactide/polyglycolide acid (PLGA) and solvent dehydrated duramater allograft (SDDA) membranes, were used and CTG was obtained from the palatal mucosa. The selected pairs of teeth were randomly assigned to one of three groups (10 pairs per group): group 1, PLGA (10 recessions) or CTG (10 recessions); group 2, SDDA (10 recessions) or CTG (10 recessions); or group 3, PLGA (10 recessions) or SDDA (10 recessions). Statistical analysis evaluated both intra- and intergroup measurements. The height of gingival recession (GR), width of keratinized tissue (KT), clinical attachment level (CAL), and probing depth (PD) were assessed at baseline and at 6, 9, and 12 months following surgery. RESULTS: The amount of root coverage was 74.3%, 69.6%, and 86.3% with PLGA, SDDA, and CTG, respectively. The gain in KT was significant in the CTG group (P<0.05). No significant differences were observed among the three groups with respect to PD and CAL. CONCLUSIONS: Results of this study indicate that all techniques led to an improvement of all clinical parameters except PD from baseline. However, CTG increased KT considerably compared to GTR. The final esthetic results were similar for the two membranes and connective tissue graft.

Absorbable Implants↗
PubMed2007

Cross-sectional evaluation of the presence of gingival recession in individuals with cleft lip and palate.

BACKGROUND: In dentistry, investigations in the field of periodontics in individuals with cleft lip and palate are scarce, with few studies on the prevalence, incidence, extension, and severity of periodontal alterations and their treatment in adults. METHODS: This study analyzed the prevalence, extension, and severity of recessions and the relationship with some etiologic factors in 200 individuals with cleft lip and palate aged 13 to 56 years. Examination comprised measurements of gingival recession, amount of keratinized mucosa, frenum insertions, and tooth positioning in the dental arch. RESULTS: Analysis of the results revealed that the prevalence of recession was high, because 75% of individuals in the sample had at least one tooth with gingival recession; 100% of individuals aged >43 years presented at least one recession, and most recessions were Miller Class I. The multiple linear regression demonstrated that recession is directly proportional to age (i.e., it increases with age); concerning the amount of keratinized mucosa, the proportion is inverse (i.e., the larger the recession, the smaller the amount of mucosa); and gingival inflammation also presented a positive correlation. CONCLUSIONS: Gingival recessions are caused by many etiologic factors, which usually act in combination. Thus, all factors causing recession should be analyzed so that planning and treatment of this clinical condition may be established, for achievement of optimal outcomes.

Adolescent↗
PubMedDate not supplied

Gingival recession at the University College Hospital, Ibadan--prevalence and effect of some aetiological factors.

Four hundred and ninety-one consecutive patients comprising 259 (52.7%) males and 232 (47.3%) females who attended the periodontology clinic of the University College Hospital Dental Centre between May 1995 and May 1996, were recruited into this study. One hundred and thirty-seven patients comprising 101 males and 36 females were found to have gingival recession of at least one tooth surface representing 27.7%. The age range of the patients investigated was 16 years to 82 years; mean age was 39.2 +/- 14.4 for males and 34.1 +/- 14.4 for females. The peak incidence of gingival recession was in the 46-55 year age group. The incidence of gingival recession increases with advancing age with 0.04% in the 16-25 year age groups as compared to 58.5% in the 56-65 year age group. The aetiologic factors which appeared to be related to gingival recession were found in the following order of frequency: malalignment; chewing stick trauma; toothbrush trauma; calculus. Eighty-eight percent (88.8%) of malaligned teeth in the age range 66 years and above had recession. A higher percentage of the subjects who used chewing stick had recession (29.4%) when compared to those who used toothbrush alone (22%) P < 0.05--this is statistically significant. Of great concern is the prevalence of recession (58%) among those subjects who used toothbrush and chewing stick together, with majority of them having generalized gingival recession. The possible reasons for these different prevalence rates of recession are discussed, measures by which incidence of gingival recession can be reduced are briefly summarized.

Adolescent↗
PubMed1991

Development of a system to assess visible and hidden gingival recession.

The accurate assessment of gingival recession is important because of soft tissue deterioration and/or the state of soft tissue health. While recession of the gingival margin is a common and important symptom of periodontal disease, it also refers to the location of the gingiva and not to its condition. Recession can occur at all tooth surfaces. This paper describes a new system designed to measure two parameters of gingival recession. One parameter of recession is visible above the gumline to an observer, while another parameter is hidden by the gingiva itself. Visible recession is the shift of the marginal gingiva to a position apical to the cemento-enamel junction. Hidden recession is obscured by gingiva and can be assessed by measuring from the free gingival margin to the level of epithelial attachment. The system developed here differs from the current indices commonly used for gingival recession, since it combines both the visual portion with the hidden portion of recession for a total score. The assessment method is similar to the calculus scoring procedure of Volpe and Manhold and is called the Gingival Recession Total (GRT) scoring system.

Gingival Recession↗
PubMedDate not supplied

The prevalence and distribution of gingival recession among U.E. dental students with a high standard of oral hygiene.

The aims of this study were to evaluate the prevalence and the distribution of the attachment loss and gingival recession at facial tooth surfaces in a population sample with a high standard of oral hygiene, at the same time, to determine the occurrence of gingival recession. An additional aim was to study the relationship between attachment loss and gingival recession and its relation to its etiologic factors. The subject sample comprised of 100 male and female dental students in the University of the East between the ages of 18 and 26 with a minimum of 25 natural teeth, no advance periodontitis or history of periodontal surgery were examined, gingival recession was scored as present whenever the free gingival margin was apical to the c.e.i. and root surface was exposed. The clinical examination involved assessment of gingivitis, probing depth, probing attachment and gingival recessions. The results of the combined cross-sectional and longitudinal analysis performed in the study demonstrated among 100 U.E. dental students with a high standard of oral hygiene showed that: 1) Facial gingival recessions was a frequent finding due to the compensatory and remodelling process caused by loss of approximal periodontal attachment; 2) Prevalence and distribution of gingival recessions is independent with the presence of attachment loss; 3) Facial gingival recessions can exist with or without attachment loss and teeth without gingival recessions may or may not present attachment loss; 4) And presence of gingival recessions in patients with a high standard of oral hygiene can either be attributed to orthodontic treatment or wrong toothbrushing technique, too much strength exerted in brushing, overbrushing, and usage of hard toothbrush bristles.

Adolescent↗
PubMed2004

Recesses along the posterior margin of the infrapatellar (Hoffa's) fat pad: prevalence and morphology on routine MR imaging of the knee.

The objective is to evaluate the prevalence and morphology of recesses along the posterior margin of the infrapatellar fat pad on routine MR imaging of the knee. MR images of 213 knees in 204 consecutive individuals were evaluated with regard to the prevalence and morphology of recesses (a "suprahoffatic" recess close to the inferior border of the patella and the previously described "infrahoffatic" recess anterior to the inferior portion of the infrapatellar plica). The recesses were analyzed with regard to synovial effusion and the condition of the anterior cruciate ligament (ACL). Anatomic dissection was made in 29 knees in 16 cadavers to verify the presence of the suprahoffatic recess. The infrahoffatic recess was present in 45% of the knees and mostly linear in shape (44%). The suprahoffatic recess was detected in 71% of the knees (45% in cadavers). Very weak to moderate positive correlation was found between the synovial effusion or the condition of the ACL and the presence and dimensions of the recesses. An awareness of the recesses in the infrapatellar fat pad is important in order to distinguish between pathology and anatomic variants on routine MR imaging of the knee.

Adipose Tissue↗
PubMed1996

Development of the facial recess: implications for cochlear implantation.

More attention is being focused on the growth and development of the facial recess because of the use of cochlear implantation in children over 2 years of age and the prospect of using implants in even younger children. The facial recess and the extended facial recess were measured in 123 temporal bones from 73 individuals ranging in age from 8 weeks in utero to 7 years after birth. The goals were to trace the development of the facial recess and to determine whether this area continues to grow into childhood. The facial recess enlarges throughout fetal life with the development of the facial canal and the tympanic annulus. Reichert's cartilage, seen early in utero in the facial recess, gradually resorbs but may persist in the newborn. In full-term infants, the facial recess reaches 3.25 mm at the oval window and 2.62 mm at the round window. The extended facial recess reaches 3.79 mm at the oval window and 3.04 mm at the round window. No statistically significant growth of the facial recess after birth could be demonstrated in this study. The data suggest that the facial recess is probably adult sized at birth and should allow surgical access for cochlear implantation in very young children.

Child, Preschool↗
PubMed1982

Human skin collagenase in recessive dystrophic epidermolysis bullosa. Purification of a mutant enzyme from fibroblast cultures.

Recessive dystrophic epidermolysis bullosa, a genodermatosis characterized by dermolytic blister formation in response to minor trauma, is characterized by an incresaed collagenase synthesis by skin fibroblasts in culture. Since preliminary studies of partially purified recessive dystrophic epidermolysis bullosa collagenase suggested that the protein itself was aberrant, efforts were made to purify this enzyme to homogeneity, so that detailed biochemical and immunologic comparisons could be made with normal human skin fibroblast collagenase. Recessive dystrophic epidermolysis bullosa skin fibroblasts obtained from a patient documented to have increased synthesis of the enzyme were grown in large scale tissue culture and both serum-free and serum-containing medium collected as a source of collagenase. The recessive dystrophic epidermolysis bullosa collagenase was purified to electrophoretic homogeneity using a combination of salt precipitation, ion-exchange, and gel-filtration chromatography. In contrast to the normal enzyme, the recessive dystrophic epidermolysis bullosa collagenase bound to carboxymethyl-cellulose at Ca(2+) concentrations at least 10 times higher than those used with the normal enzyme. Additionally, this enzyme was significantly more labile to chromatographic manipulations, particularly when serum-free medium was used. However, rapid purification from serum-containing medium yielded a preparation enzymatically equivalent to normal human skin collagenase. Like the normal enzyme, the recessive dystrophic epidermolysis bullosa collagenase was secreted as a set of two closely related zymogens of approximately 60,000 and approximately 55,000 daltons that could be activated by trypsin to form enzymically active species of approximately 50,000 and approximately 45,000 daltons, respectively. Amino acid analysis suggested slight variations between the normal and recessive dystrophic epidermolysis bullosa collagenases. Cyanogen bromide digests demonstrated peptides unique to the enzyme from each source. The recessive dystrophic epidermolysis bullosa proenzyme was significantly more thermolabile at 60 degrees C than the normal, a finding that correlated with an approximate fourfold decrease in the affinity of the mutant enzyme for Ca(2+), a known activator and stabilizer of human skin collagenase. Aside from the altered affinity for this metal cofactor, kinetic analysis of the structurally altered recessive dystrophic epidermolysis bullosa collagenase revealed that its reaction rates and substrate specificity for human collagen types I-V were identical to those for the normal enzyme. Likewise, enzymes from both sources displayed identical energies of activation and deuterium isotope effects. Antisera were raised to the normal and putatively mutant procollagenases respectively, and, although they displayed a reaction of identity in double diffusion analysis, immunologic differences were present in enzyme inhibition and quantitative precipitation studies. These studies indicate that recessive dystrophic epidermolysis bullosa is characterized by the increased synthesis of an enzymically normal, but structurally aberrant, collagenase.

Amino Acids↗
PubMedDate not supplied

Evaluation of superior rectus muscle attachment following hang-back recession in rabbit eyes.

PURPOSE: The hang-back suture technique has been advocated to decrease the risk of scleral perforation during strabismus surgery. In this study, we evaluated the muscle insertion site in rabbits 4 weeks after a hang-back recession was performed. METHODS: Twenty-five eyes of 13 rabbits underwent hang-back recessions of between 5 and 8 mm of the superior rectus muscle. Four weeks later, the attachment sites were examined. RESULTS: Four weeks following the surgery, 14 muscles (n=25, 56%) were anteriorly displaced. In the 5 mm recession group, one muscle was anteriorly displaced (n=7, 14.3%). In the 6 mm recession group, 50% of the muscles recessed were displaced anteriorly (n=8). The 7 mm hang-back recession group demonstrated forward displacement in five muscles operated (n=6, 83%) and in the 8 mm recession group, all four muscles (100%) were anteriorly displaced. The magnitude of displacement was positively correlated to the amount of the hang-back recession performed (Pearson correlation p<0.001). CONCLUSIONS: Anterior displacement of muscles using the hang-back technique in the rabbit eye is unacceptably high and occurred in 56% of the cases. A positive, statistically significant correlation exists between the amount of recession performed and the number of muscles displaced from their new insertion. Therefore, when performing large recessions using the hang-back technique displacement should be anticipated.

Animals↗
PubMed2001

Graded recessions of the superior oblique muscle: biomechanical analysis of their effects upon its vertical, torsional and horizontal force components.

PURPOSE: To obtain objective information about the effects of different amounts and directions of superior oblique muscle (SO) recession, on its three force components: torsional (incyclotorsion), vertical (depression), and horizontal (abduction). METHODS: A well known Biomechanical Model of Ocular Motility (Orbit 1.8 Gaze Mechanics Simulation), was used to simulate different amounts of recession of the superior oblique muscle, along three different and commonly used axes of recession: a) along its anatomical path (the hypothetical line uniting the trochlea and the scleral insertion of the SO); b) anteroposteriorly on the nasal side of the superior rectus muscle (recession with posterior transposition); and c) straightforward nasal transposition around the globe. Changes in its force fraction components (torsional, vertical and horizontal) were obtained from the "Mechanical State Viewer" of Orbit, for each amount of recession in three gaze positions: in and down (infra-adduction), downgaze, and out and down (infra-abduction). Several graphics were created with these data for comparison of results. RESULTS: Any one of the axes of simulated recession of the SO proved to be effective in changing the main actions of the muscle in the gaze positions that were analyzed. The effects upon any one of the oblique muscle force components, were typical for any type of recession, as would be expected from its relationships to the three axes of rotation of the globe. Significant differences were noted among procedures when progressivity of effects, according to the amount of the simulated recession, was analyzed. Qualitative changes in one or more of the force components of the SO were also found with some procedures and amounts of recession, thus confirming some complications reported in the literature. CONCLUSIONS: A separate analysis of the effects of surgery upon any one of the three force components of the SO can best be obtained with the help of biomechanical models of ocular motility as the one herein tested. Such an analysis may help dilucidate the most convenient point of recession of the SO, when seeking for a specific effect (torsional, vertical or horizontal) along with a minimization of the effects upon the rest of them.

Biomechanical Phenomena↗
PubMed2006

Prevalence and risk of traumatic gingival recession following elective lip piercing.

The aims of this study were to evaluate the prevalence, risk and odds ratios of gingival recession defects associated with elective lip piercing and wearing of stud jewelry, and to attempt to identify risk factors that might permit the incidence of recession and its severity to be predicted, using Miller's classification. Ninety-one subjects with lip piercing and labrets were evaluated with regard to gender, age, smoking history, orthodontic history, and labret characteristics. An age-matched group of 54 individuals without peri-oral piercing provided the control. Gingival recession was recorded on teeth opposing a labret in 68.13% of pierced subjects. By contrast, only 22.2% of unpierced individuals demonstrated recession. The odds ratio between pierced and control groups indicates a likelihood of recession 7.5 times greater in a pierced individual wearing a labret than in an unpierced individual. Logistical regression analysis showed that age, gender, smoking and labret configuration did not significantly influence the development of recession. Furthermore, an illustrative example indicates that piercing and provision of a labret might typically increase the risk of recession occurring from 34.4% (pre-piercing) to 80.8 %. Recession severity was greater in the pierced group, with Miller's class 2 and 3 defects observed in 18.7% of the pierced but not at all in the unpierced group. Ordinal regression identified previous orthodontic treatment as the only significant predictor of Miller's grade. We concluded that a clear link exists between lip piercing, labret use and gingival recession. Belief that labret placement and configuration can be modified to provide protection is unfounded.

Adult↗