Pathogenesis of hypospadias--more questions than answers

Most researchers believe that hypospadias arises from malformation of the penile urethra. However, this concept has been recently rejected, and it has been suggested that the opening of the urethra is "pushed forward" by growth of the perineum. In order to obtain more information on the development of the urethra, late stages of phallic development were studied in 220 rat embryos with scanning electron microscopy (SEM). In our study, signs of rupture of the urogenital membrane or fusion of the urethral folds could not be found. Therefore, we could not confirm the traditional concept for the development of the phallic urethra. A new concept of urethral development is suggested and the pathogenesis of hypospadias is discussed.     

Comparison of enamel matrix proteins and bioabsorbable membranes in the treatment of intrabony periodontal defects. A split-mouth study

BACKGROUND: Enamel matrix proteins (EMP) have recently been introduced as a new modality for regenerative periodontal treatment. However, limited information is available concerning the comparison of the treatment of intrabony periodontal defects with enamel matrix proteins and other regenerative treatment alternatives. METHODS: The aim of the present controlled clinical trial was to compare the treatment of deep intrabony periodontal defects with EMP to that with guided tissue regeneration (GTR) with bioabsorbable membranes. Sixteen patients, each of whom displayed one pair of intrabony defects located contralaterally in the same jaw, were randomly treated with EMP or with a bioabsorbable membrane. Prior to surgery and 8 months later the following parameters were evaluated by a blinded examiner: Plaque index (PI), gingival index (GI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR), and clinical attachment level (CAL). Antibiotics (amoxicillin and metronidazole) were given during the first 10 days after surgery. No statistical significant differences in any of the investigated parameters between the 2 groups were observed at baseline. RESULTS: No serious adverse events (e.g., allergic reactions or abscesses) after any of the treatments were noted during the entire observation period. Membrane exposure occurred in 7 out of the 16 GTR treated sites. Clinical examination was performed again 8 months postoperatively. Sites treated with EMP demonstrated a reduction of PD from 8.1+/-1.7 mm to 4.3+/-1.2 mm (P <0.001) and a change in CAL from 10.3+/-1.8 mm to 7.2+/-1.2 mm (P <0.001). The sites treated with GTR showed a reduction of PD from 8.3+/-1.7 mm to 4.3+/-0.7 mm (P <0.001) and a change of CAL from 10.1+/-1.9 mm to 7.1+/-1.7 mm (P <0.001). Both treatment procedures led to significant improvements of PD and CAL. However, no statistically significant differences in any of the investigated parameters were observed between the test and control group. CONCLUSIONS: It may be concluded that both therapies led to shortterm improvements of the investigated clinical parameters. Further studies of much higher power are needed to support equivalence.     

The influence of a 0.2% chlorhexidine mouthrinse on plaque regrowth in orthodontic patients A randomized prospective study part II: Bacteriological parameters

In a prospective plaque regrowth study focusing on oral hygiene during fixed appliance therapy 12 adolescent patients (mean age 14.1±1.5 years) were evaluated twice over 2-day test periods. In the randomized, double-blind study the influences of a 0.2% chlorhexidine mouthrinse (Corsodyl^®, CHX) and a commercially available dentrifice supplementing fluoride (Odol-med-3^®) were compared intra- and interindividually in a crossover design with regard to the bacteriological parameters. The bacteriological parameters of vital fluorescence, bacteriological counts (BC), colony forming units (CFU), plating efficiency (PE) and mutans streptococci (MS) were related to the clinically assessed indices of plaque and gingivitis.All parameters analyzed demonstrated significant differences between the control and the test (chlorhexidine) group. Where-as the values of BC, CFU, and PE progressively increased in the control group from T0 to T2, these parameters distinctly decreased in the chlorhexidine group. All values of vital flora (VF) scored around 75% in the control group compared to values of 30% in the test group. BC, CFU und PE correlated significantly. The score of mutans streptococci persisted or increased in the controls whereas mutans streptococci approached 0 in the chlorhexidine group. Until the 5th day of washout a clear-cut carry over of the chlorhexidine rinse on mutans streptococci as well as on the gingival index was evident.     

Substantivity of toothpaste slurries and their effect on reestablishment of the dental biofilm

OBJECTIVES: Toothpastes are good vehicles for antibacterial substances to exert a prolonged effect. This effect depends on the substantivity and ability to interfere with plaque metabolism and/or vitality. It was the purpose of this clinical, randomized 2 x 4 cell crossover study to evaluate and to compare the antibacterial effects of two toothpastes (Colgate Total(R), COL and Parodontax(R), PAR) applied as slurries on established plaque over 24 h (Part I) and their effect on 4-day plaque regrowth (Part II). Chlorhexamed(R) (0.1%; CHX) and water served as positive and negative controls. MATERIAL AND METHODS: After professional toothcleaning eight students were asked to refrain from all mechanical hygiene measures for the next 72 h. After 48 h plaque was sampled and vitality of the plaque flora examined (baseline, VF0%). The subjects then rinsed for 1 min with 15 mL of one of the test or control solutions. Every second hour up to 14 h and 24 h after rinsing, plaque sampling and staining was performed to assess plaque vitality (VF2-24, Part I). In Part II, the classical 4-day plaque regrowth design was used with two rinses (1 min) a day as the only oral hygiene measure. Vitality values were assessed on day 1 and day 4 (VF1, VF2). At day 4, teeth were stained to assess the whole mouth plaque index (PlI) and to evaluate the percentage of plaque area (PA) of the anterior teeth. RESULTS: Compared to placebo, all active rinses reduced plaque vitality significantly over a period of 24 h (Part I). PAR, COL and CHX revealed reductions of 18-31%, 28-50% and 19-50%, respectively. In Part II, similar reductions of all parameters were found for all active rinses (PAR 12-30%, COL 34-51%, CHX 40-64%). CONCLUSIONS: Colgate Total has shown a significant action on plaque regrowth and a high substantivity during 24 h, while Parodontax revealed a more moderate but still significant effect.     

Life event and treatment attributions in drug abuse and rehabilitation

How positive and negative life events are perceived by drug abusers in nearly unexplored, yet attribution theory specifies ways in which such perceptions might differentiate drug abusers from nonabusers; it also suggests how attributions might relate to treatment effects and to rehabilitation. This study tested attributions about life events by drug abusers and matched controls as the drug abusers first entered residential treatment, and again later during treatment. Attributions about success and failure in treatment were also assessed. Results showed that attribution processes significantly differentiated drug abusers from controls and that those processes were related to ultimate rehabilitation outcome. Ways in which treatment might be made more effective by focusing on attribution processes are suggested.     

Development and validation of a new instrument for the assessment of patient‐defined benefit in the treatment of acne

Background: Benefit assessment of drugs and medical products has become a legally established feature of medical research. A standardized assessment of benefits using scientifically sound and valid methods is essential. Objective: Development, validation and practical evaluation of an instrument to record patient benefit in treatment of acne. Patients and Methods: In open interviews with n = 50 patients, possible benefits of the therapy from the patients' point of view were recorded. The item pool thus generated was reviewed by a panel of dermatologists, psychologists and patients and transferred to a 23‐item questionnaire. This is used prior to therapy to assess patients' desired benefits and after therapy to record the perceived benefits. The therapy goals and the resulting benefits are then used to generate a weighted ‘Patient Benefit Index’ (PBI). The procedure has been tested for its validity and feasibility in n = 923 patients with acne. Results: Patients accepted the instrument and deemed it to be easily understandable. Additionally, the method proved itself to be internally consistent, constructively valid and sensitive to changes. Conclusions: The Patient Benefit Index (PBI) is a valid and highly accepted practical instrument for recording patient benefit. The PBI permits an individualized, patient‐weighted assessment of the benefits of acne therapy.