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PubMed2002

Pediatric supracondylar humerus fractures: the anterior approach.

OBJECTIVES: To evaluate the efficiency of the anterior approach for displaced supracondylar pediatric humeral fractures. DESIGN: A retrospective analysis. SETTING: Clinical and outpatient clinic care. PATIENTS: The anterior approach group consisted of twenty-six patients. The historical group consisted of thirty-two patients. All had a completely displaced extension-type supracondylar humerus fracture (Gartland Type III). All were operated within six hours of admission. All patients were contacted; twenty-five of the twenty-six and twenty-nine of the thirty-two patients were re-examined at the outpatient clinic. The other patients were contacted by telephone. INTERVENTION: All fractures in the anterior approach group were operated through a ventral approach: An incision was made in the cubital fossa of only the skin and subcutaneous tissue, and reduction was performed with the thumb and index finger. The fractures in the historical group were approached through a lateral or a combined lateral and medial approach. For each case in both groups fixation was done with crossed percutaneous K-wires followed by plaster of Paris splinting for two weeks. Radiographic and clinical results were evaluated in follow-up examinations. MAIN OUTCOME MEASUREMENTS: Functional and anatomic measurements were obtained at follow-up. RESULTS: In both groups no compartment syndrome or Volkmann's ischemic contracture was seen. Two in the anterior approach group and one in the historical group had an associated brachial artery injury. Early postoperative fracture displacement occurred in one of the twenty-six anteriorly approached and in four of the thirty-two historical group patients. One of the four patients in the historical group with early displacement had no cosmetic or functional loss during follow-up examinations. One patient in the anterior approach group and two patients in the historical group had a rotational deformity, one of whom also suffered a functional loss. The only other functional losses were found in two patients in the anteriorly approached group and in three patients in the historical group. CONCLUSIONS: The results of this study show that the anterior approach is safe, simple, and easy to perform. The anterior approach has good and excellent results by Flynn's criteria in 84 percent versus 75 percent in the control group (p = 0.56).

Adolescent↗

PubMed1994

Antibiotic release from impregnated pellets and beads.

Antibiotic impregnated beads are being used increasingly in the initial treatment of open fracture wounds, producing high antibiotic levels locally, over the first few days. Pellets were prepared to assess the release of the following antibiotics: benzylpenicillin, flucloxacillin, amoxycillin, amoxycillin-clavulanate (Co-Amoxiclav), ciprofloxacin, imipenem, or gentamicin; the carrier material was either polymethylmethacrylate (PMMA) or plaster of Paris (PoP). Elution of antibiotic over 72 hours from the pellets in vitro was determined using an agar-diffusion microbiologic assay. The initial rapid release of antibiotic lasted 12-24 hours, with release from PoP pellets at least four-fold greater than that from corresponding PMMA pellets. A second phase consisted of a sustained but gradually diminishing elution. The release of antibiotics from PoP pellets compared favorably with that from the PMMA beads currently used. We conclude that PoP pellets may be particularly suitable for short-term applications such as infection prophylaxis in open fractures.

Amoxicillin↗

PubMed1977

Operative treatment of the acutely ruptured lateral ligament of the ankle.

Twenty-seven patients with acute inversion injuries of the ankle were treated surgically during the past ten years. Instability indicative of rupture of the lateral collateral ligament was demonstrated by anteroposterior stress inversion roentgenograms. Ruptures of a component or components of this ligament were found at operation in every case. The ligament and capsule were repaired and the ankle was immobilized by a plaster of Paris cast for six to eight weeks. Of 26 patients available for follow-up examination, none complained of instability although nine had minor residual symptoms. Postoperative stability was demonstrated by roentgenograms in 13 patients. In the other 13, clinical examination showed that the ankles were stable on forcible inversion of the foot and ankle. Our results indicate that surgical repair offers the best prospect for successful treatment when definite passive instability can be demonstrated by properly performed stress inversion roentgenograms.

Adolescent↗

PubMedDate not supplied

Comparison of 2 wound volume measurement methods.

OBJECTIVE: To compare 2 wound volume measurement techniques, the Kundin device and stereophotogrammetry, on 2 wound shapes. DESIGN: Using 2 wound measurement techniques, the interrater and intrarater reliability and the bias and standard error of measurement of an L-shaped and a pear-shaped plaster of paris wound model were assessed. SETTING: A clinical laboratory of a school of nursing. PARTICIPANTS: Twenty-four raters, all but 2 being registered nurses, measured each of the wounds using both techniques. INTERVENTIONS: Each rater measured each wound twice using each method in a randomly assigned order defined on a card that was drawn from a box. Measurements were recorded on a researcher-designed data collection form, which included some demographic data related to each participant. MAIN OUTCOME MEASURES: The study hypothesis was that there would be no significant difference in accuracy between the 2 wound volume measurement methods. RESULTS: The least biased and most accurate technique was stereophotogrammetry, with the smallest standard of error of measurement. Interrater reliability of average ratings was identical for both methods at 0.98. For single ratings, stereophotogrammetry was slightly higher than the Kundin device. Intrarater reliability was higher on the pear-shaped wound for the Kundin device, which had lower interrater reliability, suggesting that nurses were consistent in the direction and size of personal error. Intrarater reliability for stereophotogrammetry was identical to that of the Kundin device for the L-shaped wound and lower for the pear-shaped wound. CONCLUSIONS: Although both techniques have acceptable accuracy, stereophotogrammetry is more accurate and has more clinical applications.

Adult↗

PubMed2003

Response of a calcium sulfate bone graft substitute in a confined cancellous defect.

Calcium sulfate, plaster of Paris, has a long clinical history for use as a bone graft substitute in various skeletal sites. The current authors examined the in vivo response of calcium sulfate pellets alone or in combination with autogenous bone graft in a bilateral critical-size distal femoral cancellous defect in an adult sheep model. New thick bone formation was seen in defects filled with calcium sulfate pellets alone. Increased immunostaining for bone morphogenetic protein-2, bone morphogenetic protein-7, transforming growth factor-beta, and platelet derived growth factor was seen in defects filled with calcium sulfate pellets alone and in combination with autograft. The local acidity during calcium sulfate resorption is proposed as a possible in vivo mechanism for this type of material.

Animals↗

PubMed2004

The efficacy of a hydroxyapatite composite as a biodegradable antibiotic delivery system.

Local biodegradable carriers have been studied for use as a skeletal drug delivery system. This study investigated the efficacy of a local biodegradable composite composed of hydroxyapatite, plaster of Paris, and chitosan impregnated with antibiotics to treat methicillin-resistant Staphylococcus aureus. The composite, impregnated with vancomycin, fosfomycin, or sodium fusidate was tested for its sustained elution characteristics during 3 months and compared with similarly impregnated polymethylmethacrylate using the modified disc diffusion technique. Physicochemical properties using scanning electron microscopy and xray diffraction analysis of each preparation also were analyzed. Vancomycin and fosfomycin incorporated into the hydroxyapatite composite inhibited the organism for 3 months, whereas sodium fusidate was effective only for 3 weeks. Vancomycin and fosfomycin loaded into the hydroxyapatite composite had a significantly better inhibitive effect than when loaded in polymethylmethacrylate, whereas sodium fusidate loaded in polymethylmethacrylate showed a significantly better inhibitive effect than when loaded in the hydroxyapatite composite. Scanning electron microscopy and xray diffraction analysis elucidated the patterns of each drug release profile. The local hydroxyapatite composite is a promising local biodegradable delivery system for vancomycin and fosfomycin, whereas PMMA is a better carrier for sodium fusidate in treating methicillin-resistant staphylococcus aureus osteomyelitis.

Anti-Bacterial Agents↗

PubMed2004

Leonard F. Peltier, MD, PhD, 1920-2003.

Leonard F. Peltier, MD, PhD, was an orthopaedic surgeon, academician, administrator, laboratory investigator, historian, and mentor. His career spanned nearly six decades, beginning with graduate education at the University of Minnesota (UM) under the auspices of Owen H. Wangensteen, MD, PhD. In addition to obtaining a PhD in physiology in the UM Graduate School, he completed general and orthopaedic surgery residencies and attained board certification in each specialty. He served in the US Army Occupation Force Medical Corps in Germany just after World War II. In 1957, at 37 years old, he assumed the chairmanship of the orthopaedic training program at the University of Kansas. In 1971, he couldn't resist the opportunity to become one of the founding members of the "start-up" University of Arizona College of Medicine, accepting an appointment as chair of the new orthopaedic training program, where he remained until his retirement in 1990. He took clinical problems to the laboratory, and made important scientific contributions, particularly in the area of fat embolism and in using calcium sulfate (plaster of Paris) to fill bone defects. He served on governing boards of national professional organizations and presided over the American Association for the Surgery of Trauma from 1980-1981. Throughout his career, he was fascinated by, and published extensively in, the history of medicine arena. Known fondly as "the professor" to many of his residents and colleagues, he had a pragmatic, honest, upbeat, and often humorous approach to life's challenges, valuing personal integrity above other virtues. He explored various eclectic interests far beyond his professional contributions while maintaining his family as a central priority. With his exemplary productivity and interests in the surgical and laboratory sciences, history of medicine, appreciation of fine arts, and perceptive and effective interactions with family, friends, patients, and colleagues, the memory of Leonard Peltier evokes the image of a modern-day Renaissance man.

History, 20th Century↗

PubMed2005

The efficacy of hydroxyapatite composite impregnated with amphotericin B.

We investigated the efficacy of local biodegradable composites composed of hydroxyapatite-plaster of paris and either chitosan or alginate binder impregnated with amphotericin B. Antifungal activity was tested for Candida albicans using a modified disc diffusion technique for 6 weeks and compared with similarly impregnated polymethylmethacrylate. The physicochemical properties of each preparation were evaluated using scanning electron microscopy and Fourier transform infrared spectroscopy. The antifungal activity of amphotericin B eluted from the hydroxyapatite composites was significantly greater than the polymethylmethacrylate after 7 days. The hydroxyapatite composites and the polymethylmethacrylate system sustained their antifungal activity for at least 1 month. However, after 5 weeks, the antifungal activities of the polymethylmethacrylate systems rapidly lessened, while the hydroxyapatite composites sustained their activities at a much higher level. We found no difference in antifungal activity between the hydroxyapatite composite using either the chitosan or alginate binder. Scanning electron microscopy and Fourier transform infrared spectroscopy revealed the drug release profile. The hydroxyapatite composites impregnated with amphotericin B showed superior antifungal efficacy over those loaded in polymethylmethacrylate in an in vitro study, but additional in vivo research is needed to confirm this result.

Absorbable Implants↗

PubMed2005

Polylactide-polyglycolide antibiotic implants.

Surgeons continually struggle to reduce orthopaedic infections, but no current treatment offers minimum side effects with maximum effectiveness. Antibiotics mixed in plaster of paris have been successful in treating large bony defects in patients with chronic osteomyelitis, and have the advantage of being well tolerated and absorbed by the body. Antibiotics impregnated in polymethylmethacrylate (PMMA) have offered local antibiotic delivery with some success. However, the effect of the antibiotic on the bone cement, the inconsistent elution of the antibiotic, and the need to remove the PMMA implant drives the need for a better system of antibiotic delivery. Polymers or copolymers of antibiotic-impregnated polylactic acid, polyglycolic acid or polyparadioxanone may provide an absorbable system for localized antibiotic delivery. Similar biodegradable systems used to treat small bone fractures have been successful with minimal side effects. In vitro studies have shown promising results of antibiotic elution from bioabsorbable microspheres and beads. Animal in vivo tests have shown that antibiotic impregnated polymers can successfully treat induced osteomyelitis in rabbits and dogs. These studies have provided consistent reproducible results, and now it is time to plan human trials to assess the efficacy of antibiotic microspheres implanted in infected bone and to plan in vivo and in vitro animal testing to investigate the feasibility of antibiotic-polymer-coated components.

Absorbable Implants↗

PubMedDate not supplied

Minimalistic approach to treating wrist torus fractures.

Thirty-three patients with unilateral wrist torus fractures were reviewed retrospectively. Patients were all treated with a removable plaster-of-Paris volar forearm splint and a symptom-based splinting protocol. This protocol emphasized the parents and patients deciding when to wean from the splint as their symptoms improved. Patients were followed about 4 weeks after fracture, and initial and follow-up radiographs were compared for any changes in fracture angulation. All of the fractures healed without significant clinical change in angulation or complications. The authors propose the following treatment protocol: radiographic diagnosis and application of the removable splint in the emergency department, and one orthopaedic office/clinic visit to confirm the diagnosis and provide splinting instructions. The elimination of the additional orthopaedic visit for repeat radiographs and cast removal reduces the family's time lost from school and work and the physician's time and costs.

Adolescent↗

PubMed2004

In vitro comparison of fragmentation efficiency of flexible pneumatic lithotripsy using 2 flexible ureteroscopes.

PURPOSE: Pneumatic lithotripsy has been shown to be an effective and safe intracorporeal lithotripsy modality for renal and ureteral calculi, capable of fragmenting stones of all compositions. We determined the in vitro stone fragmentation abilities of the 0.5 mm flexible pneumatic lithotripsy probe when inserted through the working channel of 2, 7.5Fr flexible ureteroscope designs (straight working channel and offset working channel at approximately 30 degrees from the long axis of the endoscope). The velocity and displacement of the pneumatic probe tip were also evaluated with the probe inserted through each endoscope. MATERIALS AND METHODS: The 0.5 mm (1.5Fr) stainless steel probe was tested at 5 deflection angles, namely 0, 12, 24, 33 and 48 degrees, at a pneumatic pressure of 2.5 bar when inserted through the offset and straight working channel ureteroscopes. A noncontact optical laser system was used to measure or calculate the displacement and velocity of the 0.5 mm probe tip at each angle of deflection with the 2 ureteroscopes. Fragmentation at all deflection angles was assessed using plaster of Paris stone phantoms with the pneumatic device on continuous mode at 2.5 bar pressure for 30 seconds. Stones were weighed after each fragmentation cycle and the percent weight lost was determined. Comparisons were made between the 2 ureteroscopes at each angle. RESULTS: Probe tip displacement was significantly better through the straight channel ureteroscope with 30% improvement at all angles tested compared to the offset channel. Moreover, a substantial decrement in tip displacement was noted as the angle of deflection increased regardless of the endoscope used. Conversely tip velocity was relatively unchanged throughout the study and it was equivalent from straight to offset channel measurements. Phantom stone fragmentation correlated inversely with the severity of the deflection angle. An approximately 80% loss of fragmentation ability was noted as the angle increased from 0 to 48 degrees. Although the pneumatic device performed better through the straight channel scope, a similar percent loss in fragmentation from 0 to 48 degrees was seen when using either endoscope. CONCLUSIONS: The flexible pneumatic 0.5 mm lithotripsy probe appears to be best used through a straight channel flexible ureteroscope, out performing use through the offset channel scope at all angles of deflection. Tip displacement and fragmentation ability were inversely related to the degree of active deflection as the angle increased from 0 to 48 degrees. Use of the flexible pneumatic probe to aid in managing renal or proximal ureteral calculi may be limited until an improved probe can be developed, allowing complete and unencumbered fragmentation throughout all angles of deflection.

Biomechanical Phenomena↗

PubMed2005

In vitro comparison of stone retropulsion and fragmentation of the frequency doubled, double pulse nd:yag laser and the holmium:yag laser.

PURPOSE: The frequency doubled, double pulse Nd:YAG (FREDDY) laser (World of Medicine, Berlin, Germany) functions through the generation of a plasma bubble. Upon bubble collapse a mechanical shock wave is generated, causing stone fragmentation. This mechanism of action is in contrast to the holmium laser, which cause stone destruction by vaporization. Observed clinical stone retropulsion and fragmentation with the FREDDY and holmium lasers has prompted a series of in vitro experiments designed to compare laser induced retropulsion and fragmentation with those of a holmium laser and pneumatic lithotrite. MATERIALS AND METHODS: For retropulsion a hands-off underwater laboratory setup, including a horizontally oriented silicone tube 1.3 cm in diameter and a holder to keep the stone phantom in contact with the quartz laser fiber or pneumatic probe, was used. Previously weighed, cylindrical Bego stone phantoms (Bego USA, Smithfield, Rhode Island) were placed in the apparatus. Stone fragmentation was performed with the FREDDY or holmium laser, or the pneumatic lithotripter. The FREDDY and holmium lasers were tested at similar pulse energy and frequency settings. As a standard for comparison, a pneumatic lithotrite was tested with a semirigid probe and single pulse settings of 100, 200 and 300 kPa. Stone phantoms underwent 30 shocks per setting. Mean net retropulsion, defined as the final resting point of the stone, as determined by direct measurement, was recorded for each setting. For fragmentation plaster of Paris stone phantoms of known weights were used to compare the fragmentation ability of each laser. Stones phantoms were placed in a hands-off underwater setup, consisting of an inverted silicon syringe and holder immersed in tap water. The laser fiber (365 microm for the holmium and 280 microm for the FREDDY) was placed through the tip of the syringe in contact with the stone phantom. A total of 24 stones were divided into 4 groups of 6 per group. Two groups were fragmented with the FREDDY laser at 300 and 400 J total energy. The other 2 groups were fragmented using the holmium laser at 300 and 480 J total energy. Fragmentation efficiency was determined as percent weight loss. RESULTS: For retropulsion at 160 mJ the FREDDY laser caused stone retropulsion to a mean distance of 7.6, 8.1 and 6.8 cm at settings of 5, 10 and 15 Hz, respectively. At 0.8 J the holmium laser retropulsed the stone to a mean distance of 3.3 and 4.9 cm at settings of 5 and 10 Hz, respectively. The pneumatic device caused stone retropulsion a mean distance of 8.5, 9.9 and 13.8 cm at pressure settings of 100, 200 and 300 kPa, respectively. The FREDDY laser generally caused less retropulsion than the pneumatic device, although this difference was only significant at the highest pneumatic lithoclast setting (p <0.05). At clinically relevant settings the FREDDY laser caused significantly more retropulsion than the holmium laser (p <0.05). For fragmentation at total energy settings of 300 and 400 J the FREDDY laser resulted in 44.9% and 86.8% weight loss, respectively (p <0.05). At settings of 300 and 480 J the holmium:YAG laser resulted in 3.3% and 7.1% weight loss, respectively (p <0.05). CONCLUSIONS: At lower frequency settings stone retropulsion was significantly greater with the FREDDY laser compared with the holmium laser. However, retropulsion was significantly less than that caused by the pneumatic lithotripter at all settings. Therefore, we recommend the use of an occlusive device, such as the Stone Cone (Boston Scientific, Natick, Massachusetts) proximal to the calculus during intracorporeal ureteral lithotripsy and in the ureteropelvic junction during percutaneous laser nephrostolithotomy. In vitro stone fragmentation was significantly greater with the FREDDY laser than with the holmium:YAG laser, suggesting that the FREDDY may offer a low cost alternative to the holmium:YAG laser lithotrite in select patients.

Equipment Design↗

PubMed1990

Oviposition diapause and other factors affecting the egg-laying of Phlebotomus papatasi in the laboratory.

Stimuli which modulate oviposition of P. papatasi were investigated to improve insectary breeding efficiency. Oviposition and survival of gravid females were observed weekly during April-December 1987, in plastic cages at 28 +/- 1 degrees C with L:D 17:7. Oviposition of controls was subject to seasonal variation despite the relatively uniform insectary conditions. From April to mid-October (summer), mean weekly oviposition ranged from 11.6 to 18.6 eggs per fly, dropping to 1.4 eggs/fly in November (winter). Monthly yields of eggs were found to correlate with the seasonal cycle of ultraviolet (UV) radiation in sunlight. This was attributed to an endogenous rhythm since the flies were not normally exposed to UV under insectary conditions. Short exposure to UV sources of 254 nm and 312 nm, but not white light, raised the low rate of oviposition in October-November from 1.4 to 16.8-29.6 eggs/female/week, but female mortality also increased highly significantly. It is suggested that the seasonal oviposition cycle of P.papatasi is set by levels of UV irradiation. In the warm season oviposition was promoted, as compared to controls, by furrows in plaster of Paris lining the bottom of cages (29.6 v. 10.2 eggs/female) and by cow manure in the cages (39.7 v. 18.2 eggs/female), but the combination of both stimuli gave no greater fecundity (40.9 v. 20.9 eggs/female). Oviposition decreased when larvae were present (3.9 v. 15.0 eggs/female) and in half-volume cages (3.9 v. 12.5 eggs/female/week). Under standard insectary conditions, mean weekly mortality-rates of P.papatasi females were 18.3 +/- 4.8% in October-November and 36.5-59.1% during the warmer months. None of the experimental conditions yielded any significant improvement in survival-rates.

Animals↗

PubMed2006

Ultrasound therapy in tendinous injury healing in goats.

The effect of ultrasound therapy on tendon injury healing was studied on 12 locally available non-descript adult goats of either sex divided equally in two groups (I and II) consisting of six animals each. The superficial digital flexor tendon (SDFT) was transected and immediately repaired with nylon (2/0) using a locking loop suture pattern under atropine-triflupromazine-lignocaine epidural analgesia and strict aseptic condition. A full limb plaster of Paris cast was applied to immobilize the operated limb for 3 days. Postoperative care was similar in both the groups. In group I, the operated limb was allowed to heal without ultrasound therapy. In group II, pulsed ultrasound therapy was started 3 days after repair of tendinous injury at an intensity of 1 W/cm(2) for 10 min daily for 10 consecutive days. The animals of both groups were evaluated clinically and haemato-biochemically on days 1, 3, 7, 15, 20 and 30 postoperatively. Air tendonograms and ultrasonography were performed on days 0, 10, 20 and 30 post-tenorrhaphy. Histopathological examination of tendon biopsy samples was performed on day 30 post-tenorrhaphy. Resolution of inflammatory swelling, pain, weight bearing and tendon gliding movement was earlier in the test group than control. Rectal temperature, total leucocyte count and differential leucocyte count did not vary significantly at various stages of observation in both the groups. Serum glucose, cortisone and serum alkaline phosphatase levels increased significantly after tendon injury repair in all the animals and decreased slowly at all subsequent intervals in control group, whereas, it was near normal in the treatment group on day 30 post-tenorrhaphy. Air tendenograms and ultrasonography examinations in the test group revealed that there was a marked regression of peritendinous adhesion between the tendon and skin on day 30 post-tendon injury repaired and the tendon at the reconstructive site attained near normal thickness and density. Adhesions were present in the reconstructed site of SDFT in all animals of the control group. Histopathologically, the granulation tissue was comparatively bettered organized at the healing site in the ultrasound-treated animals.

Animals↗

PubMed1993

Calcaneal pin traction in the management of unstable tibial fractures.

Twenty-five patients with unstable tibial shaft fractures who were initially managed with calcaneal pin traction and subsequent plaster of Paris were retrospectively reviewed to determine if this form of management would adversely affect the outcome. There were no pin track problems. Residual subtalar joint stiffness, as measured by a foot-plate goniometer, was noted in only three patients and this could not be attributed directly to this form of fracture management. All fractures went on to union. This method is a reasonable option in the management of unstable tibial fractures.

Adolescent↗

PubMed1998

Mid-trimester ultrasound diagnosis of isolated talipes equinovarus: accuracy and outcome for infants.

Seventeen fetuses were diagnosed with isolated congenital talipes equinovarus (CTEV) on mid-trimester ultrasound at the Royal Women's Hospital, Melbourne, between January, 1992 and December 1995. Sixteen of the 17 cases had an amniocentesis performed and all karyotypes were normal. The remaining case was phenotypically normal, except for a clubfoot. None of the pregnancies was complicated by any of the recognized intrauterine environmental causes of CTEV. Four of the babies were delivered prematurely and all survived the neonatal period. Six (35%) infants did not have CTEV at birth, although 2 had postural varus feet. Nine of the 11 infants who did have CTEV at birth were treated within days of birth with plaster of Paris for periods of 6 to 12 weeks. Two infants required no further treatment, 5 required orthotics and 2 required surgery. The other 2 infants with CTEV at birth were treated with orthotics at 8 weeks of age. All infants were considered to have an excellent result at the 2 year follow-up. Seven (41%) of the prospective parents received antenatal counselling by an orthopaedic surgeon and the lack of study on outcome following an ultrasound diagnosis of CTEV was the impetus for our work.

Clubfoot↗

PubMed1979

The angular bone defect and its relationship to trauma from occlusion and downgrowth of subgingival plaque.

Sixty-four sets of human teeth were collected with the aim of evaluating the role of trauma from occlusion in the etiology of destructive periodontal disease. Before the jaws were taken out, a careful bite analysis was carried out. After fixation of the jaws, impressions were taken and plaster of Paris models were made. Finally, a set of 14 radiographs were taken. On the basis of the "clinical" records postmortem, the study models and the radiographs, the jaws were sectioned. Only mesio-distal sections were included in the present analysis. The total number of interdental spaces examined was 106. The following observations were made: 1. Before any loss of periodontal fiber attachment has taken place, the configuration of the interdental septum is entirely dependent on the location of the cemento-enamel junction (CEJ) of the two neighboring teeth. The alveolar crest does not approach the apical border of the junctional epithelium closer than about 1 mm. Thus, if the CEJ is located at different levels on two neighboring teeth, the marginal termination of the interdental septum will be oblique, forming an acute angle with the "lowest" tooth. 2. Loss of periodontal fiber attachment could invariably be related to the apical growth of subgingival plaque, and downgrowth of plaque was always associated with an inflammatory process which involved lysis of the attachment fibers within a distance varying between 0.2 and 1.8 mm from the apical border of the plaque. Subsequently, the JE proliferated down to cover the denuded root surface. 3. Reduction in height of the alveolar crest could also be related to the downgrowth of plaque. The distance from plaque to bone was never found to be less than 0.5 mm and never more than 2.7 mm. The configuration of the interdental septum always seemed to be determined by the level of the plaque on the two neighboring tooth surfaces. Thus, if the plaque had reached the same level on both sides, the crest of the interdental septum assumed a horizontal outline; if plaque had proliferated down to different levels, the crest of the interdental septum was oblique and an angular defect hereby established. 4. In the present material no evidence was found to indicate that functional (traumatic) forces can act as a co-factor in the causation of angular defects. In fact, such defects were found equally often adjacent to "nontraumatized" as to "traumatized" teeth. 5. Infrabony pockets were invariably associated with downgrowth of subgingival plaque.

Dental Occlusion, Traumatic↗

PubMed2006

Comparison of fracture resistance in root canals of immature sheep teeth after filling with calcium hydroxide or MTA.

Thirty immature sheep incisor teeth were tested for their fracture resistance after various treatment modalities using calcium hydroxide (CH) or a mineral trioxide aggregate material (MTA) as a root filling. The incisors, having approximately 80% of their root growth completed, were removed from jaws of slaughtered sheep and divided into four experimental groups. The pulps were extirpated from all the teeth through the open apexes. (a) Saline group: the teeth were preserved in saline for 100 days at 6 degrees C. (b) CH group: the root canals were filled with CH and sealed apically with IRM and stored as above. (c) MTA group: the canals were filled with MTA and stored as above. (d) CH+MTA group: the canals were filled with CH and sealed with IRM. After 30 days, the CH was replaced with MTA and stored as above. At the end of the 100-day storage period, all teeth were embedded in plaster of Paris and tested for fracture strength at the cervical area in an Instron testing machine. The results showed a decrease in fracture resistance (a) of the incisors with CH in the root canals after 100 days of storage, compared to (b) teeth stored in intracanal saline and (c) teeth with 30 days of CH and then filled with MTA, and (d) those filled with MTA in the canals. In conclusion, when CH was kept in the canals of immature sheep teeth for only 30 days followed by root filling with MTA there was no significant decrease in strength of the root within an observation period of 100 days. This finding may be of importance in the decision of treatment plans for teeth with pulp necrosis and immature root formation.

Aluminum Compounds↗