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Biomedical subjects

C M Flaitz

Publications and source records attributed to C M Flaitz.

At least 55 records · Page 3Linked to original sources
PubMed1998

Argon laser irradiation effects on sound root surfaces: in vitro scanning electron microscopic observations.

OBJECTIVE: The purpose of this in vitro scanning electron microscopy (SEM) study was to evaluate the effect of low fluence (energy density of 11.5 J/cm2 and 100 J/cm2) argon laser irradiation on the surface morphology of sound root surfaces. SUMMARY BACKGROUND DATA: Previous laboratory investigations have shown that argon laser irradiation of root surfaces provided a protective effect against in vitro cariogenic challenges. METHODS: Root surfaces of extracted human molars were sectioned into treatment quarters: 1) mesiobuccal--no treatment control; 2) mesiolingual--low fluence argon laser irradiation (0.231 Watts, 11.5 J/cm2 for 10 seconds); 3) distobuccal--no treatment control; and 4) distolingual--higher fluence argon laser irradiation (2.0 Watts, 100 J/cm2 for 10 seconds). All surfaces were critical-point dried, coated with platinum and paladium under vacuum, and evaluated qualitatively for intactness, surface morphology, surface deposits, and porosities in a blinded fashion by scanning electron microscope. RESULTS: The argon lased root surfaces demonstrated alterations of root surfaces with creation of surface globular particulate material, microporosities, and depressions. Both low- and high-fluence lased root surfaces showed areas with plaque-like plates with fine punctuate oval particulate material on their surfaces. CONCLUSIONS: Argon laser irradiated root surfaces produce surface granular to globular deposits that may provide readily mobilized tooth mineral, which may become redeposited into the underlying root surface during a cariogenic challenge and enhance resistance to caries formation. In addition, microporosities created by the argon laser may provide a means for bonding fluoride-releasing restorative and preventive materials to root surfaces and further improve the root surfaces' ability to resist cariogenic challenges.

Argon↗
PubMed1998

An orthotopic floor-of-mouth cancer model allows quantification of tumor invasion.

OBJECTIVES: To establish an orthotopic murine floor-of-mouth cancer model for the analysis of the role of proteases such as urokinase-type plasminogen activator (u-PA) and the matrix metalloprotease MMP-9 (MMP-9) in in vivo invasion. STUDY DESIGN: Randomized, prospective animal study. METHODS: Two human squamous cell carcinoma cell lines, UM-SCC-1 and 022, were assayed via zymography for their in vitro secretion levels of u-PA and MMP-9. Both cell lines (5 x 10(6) cells) were injected into the cervical subcutaneous tissues of female athymic nude (nu/nu) mice superficial to the mylohyoid muscle. Mice were sacrificed after 30 days, and tumor invasion characteristics were histologically compared. Additional mice were then inoculated with invasive UM-SCC-1 cells and sacrificed 10, 30, and 40 days after inoculation to identify distinct stages of invasion. RESULTS: In vitro secretion levels of MMP-9 and activity of u-PA were higher in UM-SCC-1 cells than in 022 cells. In the in vivo studies, tumors formed from 022 cells were found to be noninvasive, whereas tumors derived from UM-SCC-1 cells progressed through distinct and readily identifiable histologic stages of invasion. These stages included invasion of adjacent muscle layers (mylohyoid, geniohyoid, and genioglossus muscles) and of associated structures (blood vessels, bone, nerve, and regional lymph nodes). A staging system was devised accordingly. CONCLUSION: We developed an in vivo quantitative cancer invasion model that allows determination of the effect of the expression and activity levels of the proteases MMP-9 and u-PA. Tumor invasion occurred in an orderly and stepwise fashion involving muscles and related vascular, nervous, and bony structures of the floor of the mouth and tongue. This orderly invasion allowed the development of a staging system. We anticipate that this model will have wide applicability in the study of in vivo tumor response to a variety of novel therapeutic approaches.

Animals↗
PubMed1998

Isolation of Lautropia mirabilis from oral cavities of human immunodeficiency virus-infected children.

Lautropia mirabilis, a pleomorphic, motile, gram-negative coccus, has been isolated from the oral cavities of 32 of 60 (53.3%) children infected with human immunodeficiency virus (HIV) and 3 of 25 (12.0%) HIV-uninfected controls; the association of L. mirabilis isolation with HIV infection is significant (P < 0.001). All children in the study, both HIV-infected children and controls, were born to HIV-infected mothers. The presence of this bacterium was not associated with clinical disease in these children. The HIV-infected children with L. mirabilis did not differ from the HIV-infected children without L. mirabilis in immunological status, clinical status, or systemic medications. The role of HIV infection itself or concomitant factors in the establishment of L. mirabilis in the oral cavity remains to be elucidated.

Child↗
PubMed1998

Role of dentinal carious lesions in the pathogenesis of oral candidiasis in HIV infection.

The authors describe a clinicopathologic study that evaluated whether dentinal carious lesions are colonized by candidal organisms--and if so, whether there is a relationship between dentinal carious lesion colonization and clinical oral candidiasis, or OC, in HIV infection. Using light microscopy, the authors examined 30 extracted teeth with dentinal carious lesions from people in each of two groups: 30 consecutively treated HIV-positive patients and 30 consecutively treated HIV-negative patients. OC was diagnosed only in HIV-positive patients (40 percent). The dentinal carious lesion pattern in both groups was similar in occlusal, root and proximal caries. Candidal colonization of carious dentinal tubules was more frequent in HIV-positive subjects than it was in HIV-negative subjects. This research shows that it may be important to restore dentinal caries in HIV-infected patients to remove a protected niche for candidal organisms.

AIDS-Related Opportunistic Infections↗
PubMed1998

Root-surface caries formation: effect of in vitro APF treatment.

To determine the effect of one and four-minute acidulated phosphate fluoride, or APF (Oral-B Minute Gel, Oral-B Laboratories) treatments on artificial caries development in root surfaces, an in vitro study was conducted. The authors created a window of exposed root surface on extracted teeth by applying acid-resistant varnish to the remaining surface. APF treatment was administered and followed by a 24-hour deionized-distilled water rinse. A window of sound root surface that had been protected from the APF treatment was exposed and served as a control. Acidified gel was then applied to the exposed root surfaces to create the artificial caries. The authors found that APF treatment significantly enhanced resistance to demineralization of root surfaces from an in vitro acidogenic challenge. However, there was little difference in effectiveness between the one- and four-minute APF treatment times.

Acidulated Phosphate Fluoride↗
PubMed1998

Secondary caries adjacent to amalgam restorations lined with a fluoridated dentin desensitizer.

PURPOSE: To determine the in vitro effect of a fluoridated dentin desensitizer solution (DentinBloc) on (1) secondary caries formation, and (2) the interfacial adaptation when used as a cavity liner before amalgam (Dis-persalloy) placement. MATERIALS AND METHODS: 24 macroscopically caries-free molars were selected. Class V cavity preparations on mesial and distal surfaces were placed along the cemento-enamel junction, providing an enamel margin and a root surface margin. DentinBloc was applied prior to alloy restoration in the experimental group for 60 s (the excess was removed with cotton pellets), while a copal cavity varnish (Copalite) was used before alloy restoration in the control group. Polarized light evaluation was performed on longitudinal sections (24 caries risk sites for enamel and dentin margins in each group). Alloy-tooth interfaces were evaluated by SEM. RESULTS: Wall lesions were present in 100% of caries-risk sites for the control group, while 58% of enamel risk sites and 50% of root risk sites had wall lesions in the DentinBloc group. Surface lesion depth was reduced 13% at enamel margins and by 18% at root margins in the experimental group when compared to the control group. Relatively small interface gaps between the alloy and tooth surfaces were seen in both groups, but these were less for the root surface margins (2-5 microns) than for the enamel margins (5-15 microns).

Analysis of Variance↗
PubMed1997

Kaposi's sarcoma-associated herpesvirus-like DNA sequences (KSHV/HHV-8) in oral AIDS-Kaposi's sarcoma: a PCR and clinicopathologic study.

Recently, a new human herpesvirus (KSHV/HHV-8) has been identified in classic, transplant, endemic, and AIDS Kaposi's sarcoma that may be involved in the pathogenesis of Kaposi's sarcoma. The purpose of this study was to evaluate oral AIDS-Kaposi's sarcoma for detection of KSHV/HHV-8 DNA. DNA extracted from 54 oral AIDS-Kaposi's sarcoma lesions (47 initial, 7 postvinblastine treated), 5 non-Kaposi's sarcoma HIV-positive lesions, and 3 non-Kaposi's sarcoma HIV-negative lesions was evaluated by polymerase chain reaction (KS330(233bp)amplicon) for KSHV/HHV-8. The AIDS-Kaposi's sarcoma study population consisted of 52 patients (51:1, men:woman; 92% men having sex with men, 8% heterosexual; mean age, 38 years; mean, CD4 59/mm3) Opportunistic infections occurred in 88% (candidiasis, 65%; Pneumocystis carinii pneumonia, 31%; nonoral Kaposi's sarcoma, 25%; mycobacterium avium-intracellulare (MAI), 16%; cytomegalovirus, 14%; herpes simplex virus, 14%). Sexually transmitted diseases occurred in 73% (gonorrhea, 37%; syphilis, 23%; condyloma, 22%; HSV, 16%). Most frequent lesion sites were palate (74%) and gingiva (17%). Most common lesion types were purple nodular (48%) and macular (42%). Histopathologic subtypes were nodular (71%), plaque (27%), and patch (2%). Polymerase chain reaction analysis detected KSHV/HHV-8 DNA in 53 of 54 AIDS-Kaposi's sarcoma lesions (47 of 47 initial, 6 of 7 postvinblastine treatment). KSHV/HHV-8 DNA was not detected in non-Kaposi's sarcoma lesions in HIV-positive or HIV-negative persons. KSHV/HHV-8 DNA sequence is present in a high proportion of oral AIDS-Kaposi's sarcoma lesions. Whether KSHV/HHV-8 is an etiologic agent or a cofactor in the development of this vascular neoplasm is uncertain and remains to be proven. Polymerase chain reaction analysis for KSHV/HHV-8 DNA sequence detection may be helpful in identifying Kaposi's sarcoma in early vascular proliferations, when the characteristic histopathologic features are not present.

AIDS-Related Opportunistic Infections↗
PubMed1997

Root caries in vitro after low fluence argon laser and fluoride treatment.

Because the numbers of dentate elderly are increasing, root caries prevention has become a great concern to the dental profession. This in vitro study evaluates the influence of combining low fluence argon laser treatment and acidulated phosphate fluoride treatment on caries initiation and progression in human root surfaces. The combination of low energy laser treatment and fluoride treatment increased the caries resistance of root surfaces when compared with no treatment and with laser irradiation treatment alone.

Acidulated Phosphate Fluoride↗
PubMed1996

Congenital heterotopic gastrointestinal cyst of the oral cavity in a neonate: case report and review of literature.

Heterotopic gastrointestinal cysts of the oral cavity are rare benign lesions which may mimic both benign and malignant neoplasms. These cysts are usually discovered during infancy, but may not appear until well into adulthood. This lesion involves the tongue and floor of the mouth in 97% of cases and has a male predilection. The cyst may range in size from less than 1 cm to 9 cm, with most lesions being 1-3 cm in size. About 30% of affected individuals have symptoms related to difficulties with feeding, swallowing and respiration. The epithelial lining is quite variable, but all cysts have an enteric lining. The histogenesis is related to entrapment of undifferentiated, noncommitted endoderm within the oral cavity during the 3rd-4th week of fetal life. The purpose of this paper is to report a congenital heterotopic gastrointestinal cyst of the oral cavity presenting in a neonate. The clinical and histopathologic features of this cyst are reviewed, as well as the histogenesis of this lesion.

Choristoma↗
PubMed1996

Herpesviridae-associated persistent mucocutaneous ulcers in acquired immunodeficiency syndrome. A clinicopathologic study.

Persistent mucocutaneous ulcers in AIDS represent a variety of disease entities. The purpose of this study was to characterize clinicopathologic features of persistent oral ulcers associated with cytomegalovirus and herpes simplex virus in AIDS. Forty-seven persons infected with HIV with persistent ulcers (mean, 2.4 ulcers/person) were included in this study. A biopsy specimen from a representative ulcer was taken from each patient. Hematoxylin-eosin, periodic acid-Schiff, cytomegalovirus, and herpes simplex virus immunocytochemical stains were performed on tissue sections. The most common sites of involvement were the buccal/labial mucosa (27%), tongue (25%), and gingiva (18%). Mean ulcer size was 1.8 cm with a mean duration of 5.6 weeks. The ulcerogenic viral agents were cytomegalovirus alone in 53% of cases, cytomegalovirus and herpes simplex virus coinfection in 28% of cases, and herpes simplex virus alone in 19% of cases. Treatment response to ganciclovir with or without topical steroids resulted in lesion resolution in the cytomegalovirus and cytomegalovirus/herpes simplex virus groups; however, recurrence/resistance was relatively high (23%). Herpes simplex virus/cytomegalovirus ulcers responded to oral acyclovir in combination with systemic ganciclovir. Increasing the oral acyclovir dosage resulted in resolution of herpes simplex virus-only ulcers in all but one case. Cytomegalovirus and herpes simplex virus are associated with persistent mucocutaneous ulcers in AIDS. These lesions responded to systemic antiviral therapy but are difficult to differentiate from other ulcerogenic diseases such as aphthous major, necrotizing stomatitis, and ulcerations not otherwise specified without biopsy and histopathologic examination.

AIDS-Related Opportunistic Infections↗
PubMed1996

Expression of keratinocyte growth factor in periapical lesions.

The epithelial proliferation associated with inflammatory periapical lesions and with periapical cyst formation represents an interesting but poorly understood pathological change. Keratinocyte growth factor (KGF) is a recently identified growth factor that is produced by stromal fibroblasts and acts specifically to stimulate epithelial growth and differentiation. To investigate its possible role in the activation of the normally quiescent rests of Malassez, we examined the expression of KGF by in situ hybridization of sections of normal periodontal ligament (PDL) and of 12 periapical granulomas or cysts. Normal PDL and periapical granulomas with scant inflammatory infiltration showed few cells expressing message for KGF. However, KGF-expressing cells were found in the connective tissue stroma close to dense foci of inflammatory cells and to proliferating epithelial elements and cystic epithelial linings. Examination of tissues by the reverse-transcription polymerase chain reaction (RT-PCR) showed KGF expression in 4 specimens of periapical lesions but low or undetectable levels in normal PDL. These observations suggest that the induction of KGF expression in the stromal cells of periapical lesions may play an important role in stimulating the epithelial proliferation associated with cyst formation.

Base Sequence↗
PubMed1996

Bond strength of composite to sound and artificial carious dentin.

PURPOSE: To determine the in vitro bond strength of a composite (Herculite XRV) to sound dentin and artificial carious lesions in dentin. MATERIALS AND METHODS: Buccal and lingual surfaces from extracted human molar teeth were ground to expose sound dentin surfaces. The buccal surface was maintained as sound dentin, while an artificial carious lesion was created in the lingual surface using an acidified gelatin gel. A bonding agent (Optibond) was applied to both buccal and lingual surfaces with and without prior etching with 37.5% phosphoric acid. The composite was applied and debonded under tension after 24 hours in water at 37 degrees C. RESULTS: Both sound dentin (23.1 MPa) and etched sound dentin (22.2 MPa) had similar bond strengths, whereas artificial carious lesions in dentin that had been etched (11.8 MPa) and non-etched dentin lesions (8.8 MPa) had significantly lower bond strengths. Adhesive failures were greatest for dentin lesions (60-95%) and least for sound dentin(40-50%). Etching with phosphoric acid did not improve the bond strength of composite to sound dentin or artificial carious lesions in dentin.

Acid Etching, Dental↗