Skeletal stability and relapse patterns after Le Fort I osteotomy using miniplate fixation in patients with isolated cleft palate

We present a series of 14 consecutive isolated cleft palate patients aged 17 to 25 years (mean 19 years) who underwent Le Fort I maxillary advancement fixed with miniplates by the senior author (Posnick) over the period 1987-1991. Ten of the patients underwent autogenous bone grafting; all were stabilized intraoperatively with four miniplates, a prefabricated acrylic splint, and intermaxillary fixation. The patients were analyzed to determine amount and timing of horizontal and anterior and posterior vertical relapse, correlation between advancement and relapse, effect of a pharyngoplasty in place at time of osteotomy, effect of performing multiple jaw procedures, and maintenance of overjet and overbite. Tracings of preoperative and serial postoperative lateral cephalograms (immediate, 6 to 8 weeks, and 1 year) were analyzed to calculate horizontal and vertical maxillary changes and the amount of overjet and overbite maintained. Clinical follow-up ranged from 1.5 to 5.5 years (mean 2.5 years). No significant difference was seen in vertical or horizontal change or relapse between patients who had maxillary surgery alone (n = 10) and those who had operations in both jaws (n = 4), nor did outcome vary significantly for those who had a pharyngoplasty in place (n = 8) at the time of their Le Fort I osteotomy. The mean "effective" maxillary advancement for the group was 6.4 mm, with 5.4 mm maintained 1 year later (mean relapse 1.0 mm).(ABSTRACT TRUNCATED AT 250 WORDS)     

Surgical refinement of the operative procedure for a minor degree of mandibular prognathism

Although sagittal splitting ramus osteotomy is used widely for mandibular prognathism and even for that of a minor degree, a long duration of preoperative and postoperative orthodontic treatment is required. Conversely, mandibular segmental osteotomy has often been used to correct a minor degree of mandibular prognathism without specific orthodontic treatment. Here we describe a surgical refinement accomplishing mandibular segmental osteotomy, reduction genioplasty by double horizontal osteotomies, and decortication of the middle portion of the osteotomies for a minor degree of mandibular prognathism. The amount of setback is limited to 4 to 5 mm, no intermaxillary fixation is required, and no orthodontic treatment, in principle, is needed. This procedure can obtain a rapid aesthetic improvement. We used this procedure in 11 patients (7 females and 4 males) with a minor degree of mandibular prognathism. The amount of setback of the mandibular anterior portion was 4 to 5 mm, and satisfactory results were obtained in all patients.     

Computerized cephalometric evaluation of orthognathic surgical precision and stability in relation to maxillary superior repositioning combined with mandibular advancement or setback

PURPOSE: A computerized, cephalometric, orthognathic surgical program (TIOPS) was applied in orthognathic surgical simulation, treatment planning, and postoperatively to assess precision and stability of bimaxillary orthognathic surgery. PATIENTS AND METHODS: Forty consecutive patients with dentofacial deformities requiring bimaxillary orthognathic surgery with maxillary superior repositioning combined with mandibular advancement or setback were included. All patients were managed with rigid internal fixation (RIF) of the maxilla and mandible and without maxillomandibular fixation (MMF). Preoperative cephalograms were analyzed and treatment plans produced by computerized surgical simulation. Planned, 5-week postoperative and 1-year postoperative maxillary and mandibular cephalometric-positions were compared. RESULTS: In the mandibular advancement group, the anterior maxilla was placed too far superiorly, with an inaccuracy of 0.4 mm. The posterior maxilla and the anterior mandible were placed in the planned positions. The lower posterior part of the mandibular ramus was placed too far anteriorly, with an inaccuracy of 2.0 mm. However, the mandibular condyles were accurately placed. In the setback group, the anterior maxilla was placed too far superiorly and posteriorly, with a vertical and sagittal inaccuracy of 1.0 mm and 0.7 mm, respectively. The posterior part of the maxilla was placed in a posterior position with an inaccuracy of 1.9 mm. The anterior mandible was placed too far anteriorly with an inaccuracy of 0.9 mm. The lower posterior part of the mandibular ramus was placed in a posterior position with an inaccuracy of 0.9 mm. However, the mandibular condyles were accurately placed. The statistical analysis of the 1-year stability data showed that the maxilla had moved 0.3 mm posteriorly in the advancement group and the lower incisors had moved 0.8 mm superiorly. No other significant positional maxillary or mandibular changes were found. In the setback group, the maxilla had moved 0.5 mm posteriorly, the anterior mandible 0.5 mm anteriorly, and the lower incisors 0.7 mm superiorly. No significant positional changes were seen in the mandibular ramus. CONCLUSION: The TIOPS computerized, cephalometric, orthognathic program is useful in orthognathic surgical simulation, planning, and prediction, and in postoperative evaluation of surgical precision and stability. The simulated treatment plan can be transferred to model surgery and finally to the orthognathic surgical procedures. The results show that this technique yields acceptable postoperative precision and stability.     

In vivo treatment with recombinant IL-12 protects C57BL/6J mice against secondary alveolar echinococcosis

A sample of 259 patients with vertical maxillary hyperplasia, mandibular hypoplasia and anterior vertical open bite, collected from three different institutions, was analysed regarding temporomandibular joint (TMJ) sounds, condylar remodelling, and condylar resorption. All patients underwent Le Fort I osteotomies, and bilateral sagittal split advancement osteotomies were performed in 117 patients. Intraosseous wire fixation was used in 149 and rigid internal fixation in 110 patients. Cephalometric and orthopantomographic radiographs were available before surgery, immediately after surgery, one year postoperatively and at the latest follow up. The mean follow up was 69 months (range 20-210 months). The number of patients with TMJ sounds decreased from 38% to 31%. At the latest follow up 23.6% of the patients showed condylar remodelling, 7.7% unilateral condylar resorption and 7.7% bilateral condylar resorption. Condylar contours, as assessed on orthopantomographic radiographs, were classified as five different types. Condyles with preexisting radiological signs of osteoarthrosis or having a posterior inclination were at high risk for progressive resorption. Female patients with severe anterior open bite, high mandibular plane angle and a low posterior-to-anterior facial height ratio, who underwent a bimaxillary osteotomy, were prone to condylar resorption. Bone loss was predominantly found at the anterior site of the condyle. The incidence of condylar resorption was significantly higher after bimaxillary osteotomies (23%) than after only Le Fort I intrusion osteotomies (9%). Avoidance of intermaxillary fixation by using rigid internal fixation tended to reduce condylar changes, in particular in patients who underwent only a Le Fort I osteotomy. Rigid internal fixation in bimaxillary osteotomies resulted in condylar remodelling in 30% and progressive condylar resorption in 19% of the patients. Condylar changes were not significantly different after using either miniplate osteosynthesis or positional screws in bilateral sagittal split osteotomy procedures.     

板坯连铸结晶器数值模拟

运用Fluent 6.3对板坯连铸结晶器进行数值计算,研究拉速、水口浸入深度及水口开口角度对流场的影响.结果表明:对于断面1400 mm×230 mm结晶器,随拉速增加,液面最大水平和垂直流速均增加,而窄边冲击点的位置基本不变,随距液面距离增加,窄边速度先增加后减小,直至趋向于零;当拉速超过1.2 m.min-1时,液面水平速度增加明显.随水口浸入深度增加,液面最大水平流速减小,浸入深度超过140 mm时,最大水平流速变化不明显;垂直于液面方向的最大速度逐渐增加;对窄边冲击点影响较小.随水口开口向下角度增加,液面最大水平流速减小后增加,水口开口向下12.5°时液面最大水平流速最小,而水口开口向下10°~12.5°时窄边冲击点速度最小.      

Orthognathic surgery: a hierarchy of stability

The stability and predictability of orthognathic surgical procedures varies by the direction of surgical movement, the type of fixation, and the surgical technique employed, largely in that order of importance. The most stable orthognathic procedure is superior repositioning of the maxilla, closely followed by mandibular advancement in patients in whom anterior facial height is maintained or increased. (If facial height is decreased by upward rotation of the chin, stability is compromised). The combination of moving the maxilla upward and the mandible forward is significantly more stable when rigid internal fixation is used in the mandible. Forward movement of the maxilla is reasonably stable, with or without rigid internal fixation, but mandibular setback often is not stable, and downward movement of the maxilla that creates downward rotation of the mandible is unstable. For mandibular setback, the inclination of the ramus at surgery appears to be an important influence on stability. It has been suggested that both interpositional synthetic hydroxyapatite grafting and simultaneous ramus osteotomy improve the stability of downward movement of the maxilla, but this has not been well documented. In two-jaw Class III surgery, the stability of each jaw appears to be quite similar to that of isolated maxillary advancement or mandibular setback. The least stable orthognathic procedure is transverse expansion of the maxilla. Although surgically assisted rapid palatal expansion has been suggested as a more stable alternative to segmental Le Fort I osteotomy, the patterns of movement resulting from the two procedures are different, and differences in stability have not been established.     

Soft tissue changes after superior repositioning of the maxilla with Le Fort I osteotomy: 5-year follow-up

Long-term changes in soft tissue landmark positions were examined in 49 patients following superior repositioning of the maxilla by Le Fort I osteotomy. From presurgery to 1 year, on average the upper lip moved up one third the distance that the upper incisor and point A did, but there was considerable variability. In 25% of the patients the upper lip moved up more than 2 mm, and in 6% it moved up more than 4 mm. As the mandible rotated upward and forward in response to the maxillary movement, soft tissue movements paralleled the adjacent hard tissue movements almost exactly in the absence of genioplasty. From 1 to 5 years postsurgery, in 25% of the patients the maxilla moved downward more than 2 mm, and the mandible rotated down and back, often without relapse of occlusal relationships. In both jaws, long-term changes in soft tissue landmarks exceeded hard tissue changes, meaning soft tissue points tended to move downward even if hard tissue points were stable and moved down more than the corresponding hard tissue points when skeletal changes occurred.     

Culture of marrow stromal cells derived from bone marrow specimens formed at fracture site of human long bone

Insult of temporomandibular joints in infancy may result in severe micrognathia with ankylosis. These patients require tracheostomy and a pureed diet for survival. Between July of 1987 and December of 1990, we treated eight patients with severe micrognathia and ankylosis of one or both temporomandibular joints. Preoperative range of motion at the central incisors was 3.2 +/- 2.1 mm (mean +/- SD). Patients underwent functional reconstruction of one (n = 3) or both (n = 5) temporomandibular joints using costochondral grafts and mandibular advancement at 10.4 +/- 1.7 years of age (mean +/- SD). Rigid fixation of bone grafts with early remobilization was achieved in all cases. Average mandibular advancement was 23.8 +/- 3.7 mm (mean +/- SD), and average elongation was 21.4 +/- 3.3 mm (mean +/- SD). Range of motion at the central incisors was 27.4 +/- 4.2 mm (mean +/- SD) 1.7 +/- 0.8 years (mean +/- SD) postoperatively. Seven patients had tracheostomies prior to surgery, and all were successfully decannulated within 6 months postoperatively. One patient was treated with closed capsulotomy under general anesthesia. Two were treated with open capsulotomy and fascial flap transposition. Functional reconstruction of this deformity in mixed dentition offers these unfortunate individuals significant predictable improvement.     

Treatment response to maxillary expansion and protraction

A prospective clinical trial was conducted to determine the skeletal and dental contributions to the correction of overjet and overbite in Class III patients. Thirty patients (12 males and 18 females with a mean age of 8.4 +/- 1.7 years) were treated consecutively with protraction headgear and fixed maxillary expansion appliances. For each patient, a lateral cephalogram was taken 6 months before treatment (T0); immediately before treatment (T1); and 6 months after treatment (T2). The time period (T1-T0) represented changes due to 6 months of growth without treatment; (T2-T1) represented 6 months of growth and treatment. Each patient served as his/her own control. Cephalometric analysis described by Bj?rk (1947) and Pancherz (1982a,b) was used. Sagittal and vertical measurements were made along the occlusal plane (OLs) and the occlusal plane perpendicular (OLp), and superimposed on the mid-sagittal cranial structure. The results revealed the following: with 6 months of treatment, all subjects were treated to Class I or overcorrected to Class I or Class II dental arch relationships. Overjet and sagittal molar relationships improved by an average of 6.2 and 4.5 mm, respectively. This was a result of 1.8 mm of forward maxillary growth, a 2.5-mm of backward movement of the mandible, a 1.7-mm of labial movement of maxillary incisors, a 0.2-mm of lingual movement of mandibular incisors, and a 0.2-mm of greater mesial movement of maxillary than mandibular molars. The mean overbite reduction was 2.6 mm. Maxillary and mandibular molars were erupted occlusally by 0.9 and 1.4 mm, respectively. The mandibular plane angle was increased by 1.5 degrees and the lower facial height by 2.9 mm. Individual variations in response to maxillary protraction was large for most of the parameters tested. Significant differences in treatment changes between male and female subjects were found only in the vertical eruption of mandibular incisors and maxillary and mandibular molars. These results demonstrate that significant overjet and overbite corrections can be obtained with 6 months of maxillary protraction in combination with a fixed expansion appliance.     

Skeletal stability after mandibular advancement: a comparison of two rigid internal fixation techniques

OBJECTIVE: To compare two different methods of rigid fixation for any difference in postoperative stability after mandibular advancement. MATERIAL AND METHODS: Thirty-eight patients with Class II malocclusion treated by bilateral sagittal split osteotomy (BSSO) and mandibular advancement were selected for this retrospective study. Group A (n = 16) had noncompressive bicortical screws inserted in the gonial area through a transcutaneous approach and Group B (n = 22) had the bone segments fixed with unicortical screws and miniplates on the lateral surface of the mandibular body. Cephalograms were taken preoperatively, 2 days postoperatively, and 6 months after the operation, and a computer program was used to superimpose the three cephalograms and register the advancement and postoperative instability. RESULTS: There was a minimal difference in advancement of the mandible in the two groups. Statistical analysis showed no significant difference in postsurgical stability. However, positive correlation between the amount of advancement and the amount of postsurgical instability was demonstrated using a linear multiple regression test (P = .0002). CONCLUSION: This study indicates that the two different methods of internal rigid fixation of the segments after surgical advancement of the mandible give equal stability postoperatively and their use is a matter of surgical choice.     

Mercury neurotoxicity in rats and humans emphasizes current trends in neurotoxicology

We have developed a method of intermaxillary fixation using beads and wires. This method was effective in mandibular fractures that underwent both open and closed reduction. Our procedure is simple, requires little time, and is inexpensive. We also found several advantages of our technique when compared with the classic arch bar, wire, and eyelet method of intermaxillary fixation.     

Stability of maxilla downgrafting after rigid or wire fixation

PURPOSE: This article compares the long-term outcomes of rigid internal fixation with wire fixation. PATIENTS AND METHODS: In this retrospective study, nine cases of vertical midface augmentation in which rigid fixation was used were compared with 11 cases with wire fixation. One surgeon completed all cases for the rigid fixation group, and another surgeon completed the cases in the wire fixation group. RESULTS: Follow-up was 16 +/- 11 months for the rigid fixation group and 20 +/- 12 months for the wire fixation group. Inferior movement at the anterior portion of the maxilla was 7.0 +/- 2.9 mm with rigid fixation and 4.5 +/- 3.6 mm with wire fixation (P < .05). Postsurgical superior movement (relapse) was 0.4 +/- 0.4 mm with rigid fixation and 2.4 +/- 2.4 mm with wire fixation (P < .01). Inferior movement at the posterior maxilla was 3.1 +/- 0.2 mm with rigid fixation and 2.8 +/- 2.3 mm with wire fixation. Postsurgical superior movement (relapse) was 0.8 +/- 0.4 mm with rigid fixation and 0.5 +/- 2.3 mm with wire fixation, which was not significantly different. CONCLUSION: This comparison showed downgrafting of the maxilla using autogenous bone harvested from the iliac crest and rigid internal fixation to be a predictable and stable procedure.     

A prospective evaluation of Bass, Bionator and Twin Block appliances. Part I--The hard tissues

A prospective clinical study with a random allocation of 47 adolescent patients to three different functional appliance groups was established and compared with an untreated control group over a 9-month period. Treatment was undertaken with either a Bionator, Twin Block, or Bass appliance. Pre- and post-treatment cephalograms were used to quantify the skeletal and dentoalveolar changes produced by the appliances and compared with those observed in the control group as a result of growth. Both the Bionator and Twin Block appliances demonstrated a statistically significant increase in mandibular length (3.9 +/- 2.7 mm; 3.7 +/- 2.1 mm, respectively) compared with the control group (P < 0.05), with an anterior movement of pogonion and point B. Highly statistically significant increases (P < 0.01) were seen in lower face heights for all the appliance groups compared with the control group. The Twin Block group showed the least forward movement of point A due to a change in the inclination of the maxillary plane. The Bionator and Twin Block groups showed statistically significant reductions in the inclination of the upper incisors to the maxillary plane (P < 0.05). The Bass group showed minimal change in the inclination of the lower labial segment to the mandibular plane. The Bionator group demonstrated the greatest proclination of the lower labial segment (4.0 +/- 3.6 degrees). Clinically important changes were measured in all the appliance groups when compared with the control group. Differences were also identified between the functional appliance groups. The Twin Block appliance and, to a lesser extent, the Bionator appeared the most effective in producing sagittal and vertical changes.     

Impedance of pacemaker leads: correlation of different methods

PURPOSE: Four children with an osteomyelitic process in the jaw bones while on cytotoxic chemotherapy were treated by radical surgery and antimicrobial chemotherapy. PATIENTS AND METHODS: Symptoms (local swelling and pain in the jaw, necrotic gingivitis, and spontaneous loss of teeth) appeared 3 weeks, 4 weeks, and 8 months after diagnosis of leukemia, and 8 days posttransplant in a patient with severe aplastic anemia. Three had the process in the mandible and one in the maxilla. Specific diagnoses of Aspergillus flavus, Saccharomyces cerevisiae, and Actinomyces species were obtained histologically from surgical samples. Treatment was radical surgery to remove all infected and necrotic tissue: removal of a substantial part of the mandible and loss of seven to eight permanent teeth in those with mandibular lesions. Actinomycosis was treated with penicillin for 2 years. The patients with fungal lesions received amphotericin B for 2, 5, and 6 months, with adjuvant itraconazole, fluconazole, or 5-fluorocytosine for 9-12 months. Anti-cancer chemotherapy was continued. RESULTS: All the bony lesions healed. The patient with acute myeloid leukemia died in relapse 1 year postdiagnosis; her aspergillus osteomyelitis had been inactive for 8 months. The other three patients are alive and well 1.9, 2.1, and 1.9 years after termination of antimicrobial therapy. CONCLUSIONS: We emphasize the necessity of specific diagnosis from appropriate surgical samples and conclude that in patients undergoing chemotherapy bony lesions caused by opportunistic microorganisms may be curable with aggressive surgery and prolonged medication.     

Hemispheric control of motor function: a whole brain echo planar fMRI study

A sample of 130 patients with vertical maxillary hyperplasia; mandibular hypoplasia with a high mandibular plane angle; narrow, tapered maxillary dental arch form; and anterior vertical open bite were collected from three different institutions to evaluate the stability of transverse maxillary arch dimensions after correction of the open bite. Surgical treatment consisted of Le Fort I or bimaxillary osteotomies. Intermolar, interpremolar, and anterior arch widths were measured three-dimensionally on dental casts using a Reflex microscope, and transverse stability after orthodontic or surgical maxillary expansion was analyzed. Orthodontic expansion followed by a one-piece Le Fort I intrusion osteotomy was performed in 77 patients, and surgical maxillary expansion by a multisegment Le Fort I intrusion osteotomy was performed in 53 patients. The increase of transverse arch width and the relapse after orthodontic or surgical expansion were not significantly different. The transverse arch width in these two groups did not relapse in 20% of the patients after a mean follow-up of 69 months. An additional bilateral sagittal split osteotomy had no detectable effect on stability. Patients who underwent a multisegment Le Fort I osteotomy stabilized with rigid internal fixation showed better transverse stability than those with intraosseous wire fixation and maxillomandibular fixation. Maxillary intermolar and interpremolar arch width relapses were not correlated with tongue interposition or loss of interdigitation. The relapse of these arch widths showed significant correlations with clockwise rotation of the mandible but not with changes of overbite or overjet.     

A 3-year experience with guided tissue regeneration procedures

The Guided Tissue Regeneration (GTR) procedures are promoting a clinically and radiologically as well as histologically verifiably periodontal attachment gain. The objective of the study was to evaluate the clinical efficacy of these GTR techniques. In the past four years different barrier membranes (Gore-tex, Resolut and Guidor) were used around 318 teeth of 196 patients. 169 periodontal defects of 140 patients were followed up at least for two years. 54 patient had chronic adult type periodontitis, 67 suffered with rapidly progressing periodontitis and 15 had different severe mucogingival lesions. 111 vertical bony defects, 43 Class II-III furcation lesions and 15 mucogingival lesions were surgically corrected. The average preoperative probing depth (PD) and the clinical attachment loss (CAL) of the vertical bony defects were 5.3 +/- 1.7 mm and 6.2 +/- 1.9 mm respectively. The PD of the deepest Class III furcation lesion was 11 mm. The average gingival recession of the mucogingival lesions was 4.5 +/- 1.1 mm. The GTR technique provided the best results in the Class II-III furcation lesions, where an average 2.4 +/- 0.9 clinical attachment gain was observed one year postoperatively. The GTR techniques provided an average 1.8 +/- 1.2 mm attachment gain in the vertical bony crater cases. In both groups of cases a marked gingival recession followed the healing and the periodontal regeneration. In this way the average reduction in the probing depth exceeded the average attachment gain by more that 1.5 mm. 1 year after the operation the average radiologic bone fill was about 0.9-1.2 mm. The resorbable barrier membranes resulted in clinically significant root coverage and an average 3.5 +/- 1.7 mm gain in the width of keratinized gingiva. The success or failure of our cases were mainly determined by the patient's compliance, the level of the postoperative professional and individual oral hygiene and the number of periodontal recalls. These findings are also underlining the importance of the high standard of oral hygiene in the postoperative periodontal regeneration.     

Condylar position with rigid fixation versus wire osteosynthesis of a sagittal split advancement

PURPOSE: In this randomized clinical study, two groups of patients who underwent a bilateral sagittal split osteotomy and either wire osteosynthesis or rigid fixation were compared. PATIENTS AND METHODS: Cephalometric radiographs obtained before surgery, immediately after surgery, and at 8 weeks, 6 months, and 1 and 2 years after surgery were available for 125 of these patients, 63 with wire fixation and 62 with rigid fixation. All were traced by an independent examiner, and vertical and horizontal changes in condylar position were recorded for each period. RESULTS: Condylar movement was slightly different with the two fixation techniques beyond 8 weeks postsurgery, but the ultimate position of the condyle was not different. The condyles in both groups moved posterior and superior. There initially was a correlation between the amount of advancement and the amount the condyle moved inferior in both groups, but this diminished with time. In addition, there was a weak but significant positive relationship between forward rotation of the proximal segment and superior condylar position immediately after surgery, which did not exist at later periods. CONCLUSIONS: Whether wire osteosynthesis or rigid fixation was used, the ultimate condylar position was posterior and superior after a bilateral sagittal split osteotomy to advance the mandible. No single factor could be identified to account for this change. It is suggested that change in mechanical load may have resulted in remodeling and adaptation of the condyles.     

Mandibular fractures: the problem patient

Of 110 adult patients with 163 mandibular fractures treated at University of Pennsylvania Graduate Hospital from 1964 to 1974, 17% had a history of previous mandibular fractures. All patients' medical records and X-rays were reviewed. Because of the characteristics of this patient population, it seems well suited for discussion as a problem group. Mandibular fractures in this urban area are most commonly caused by blows of a fist and the patient is often intoxicated, which impedes diagnosis, delays treatment, and probably results in further complications from injuries. Patients frequently do not comply with treatment recommendations, do discontinue immobilization, and fail to return for followup, even for removal of intermaxillary fixation. Almost one third had insufficient teeth for fixation; many had poor oral hygiene, and teeth in the fracture line, which led to complications. Osteomyelitis resulting in nonunion and requiring bone grafting occurred in seven patients. Recommended are: simplest fixation methods, minimal amounts of surgery, and as few extractions as possible. Experience from this patient group may be of help whenever a problem patient is seen with a mandibular fracture.     

Reaction times of vertical prosaccades and antisaccades in gap and overlap tasks

Horizontal saccadic reaction times (SRTs) have been extensively studied over the past 3 decades, concentrating on such topics as the gap effect, express saccades, training effects, and the role of fixation and attention. This study investigates some of these topics with regard to vertical saccades. The reaction times of vertical saccades of 13 subjects were measured using the gap and the overlap paradigms in the prosaccade task (saccade to the stimulus) and the antisaccade task (saccade in the direction opposite to the stimulus). In the gap paradigm, the initial fixation point (FP) was extinguished 200 ms before stimulus onset, while, in the overlap paradigm, the FP remained on during stimulus presentation. With the prosaccade overlap task, it was found that most subjects (10/13)-whether they were previously trained making horizontal saccades or naive-had significantly faster upward saccades compared with their downward saccades. One subject was faster in the downward direction and two were symmetrical. The introduction of the gap reduced the reaction times of the prosaccades, and express saccades were obtained in some naive and most trained subjects. This gap effect was larger for saccades made to the downward target. The strength of the updown asymmetry was more pronounced in the overlap as compared to the gap paradigm. With the antisaccade task, up-down asymmetries were much reduced. Express antisaccades were absent even with the gap paradigm, but reaction times were reduced as compared to the antisaccade overlap paradigm. There was a slight tendency for a larger gap effect of downward saccades. All subjects produced a certain number of erratic prosaccades in the antitasks, more with the gap than with the overlap paradigm. There was a significantly larger gap effect for the erratic prosaccades made to the downward, as compared to the upward, target, due to increased downward SRTs in the overlap paradigm. Three subjects trained in both the horizontal and the vertical direction showed faster SRTs and more express saccades in the horizontal directions as compared to the vertical. It is concluded that different parts of the visual field are differently organized with both directional and nondirectional components in saccade preparation.     

Cloning, characterization, and chromosomal localization of human superillin (SVIL)

The specific aim of this study was to determine the response of alveolar bone after it was augmented vertically using distraction osteogenesis and subsequently loaded with implant restorations. Four dogs each had four implants placed horizontally into an edentulous mandibular quadrant and, after integration, a distraction osteogenesis device was fabricated in the laboratory. An osteotomy was made to allow the crest of the alveolar ridge to be distracted vertically. After 10 mm of vertical distraction, the device was stabilized with light cured resin. Following bone fill confirmation of the distraction gap at 10 weeks, two implants were placed into the ridges, one in distracted bone and one in nondistracted bone. After 4 months for implant integration, freestanding prostheses were fabricated. Crestal bone levels were evaluated throughout the period of function. Animals were sacrificed after 1 year of loading, for histologic evaluation of the bone. The vertical ridge augmentation averaged 8.85 +/- 1.05 mm after 10 weeks of healing following distraction, without change over 1 year of implant loading. Histologic examination showed that bone had formed between the distracted segments, creating an augmented ridge. The average thickness of the labial cortex in the distraction gap was significantly thinner than the lingual cortex in distracted bone and the lingual and labial nondistracted cortical bone. The presence of the dental implant did not significantly affect cortical bone thickness. Serial sections showed that implants remained integrated and functional without soft tissue inflammation. Dental implants placed into alveolar ridges augmented with the technique of distraction osteogenesis maintained bone and were functional for the length of this study.