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Biomedical subjects

L Laurell

Publications and source records attributed to L Laurell.

At least 19 recordsLinked to original sources
PubMed2000

A retrospective radiographic outcome assessment study of intra-bony defects treated by osseous surgery or by bone graft procedures.

BACKGROUND: Intra-bony defects remain a significant therapeutic problem in periodontal therapy. Various non-surgical and surgical treatment modalities are being used. The long-term stability following treatment of intra-bony defects is poorly documented. OBJECTIVES: To assess changes in intra-bony defects after either osseous surgery or open flap debridement in combination with grafting procedures with demineralized freeze-dried bone allografts (DFDBA). METHOD: Pre- and post-surgical computer digitized images of intra-oral radiographs from 60 patients who had received periodontal surgery to manage intrabony defects were analyzed by linear measurements. RESULTS: 36 patients were treated with osseous surgery and 24 had received flap procedures and grafting with DFDBA. Post-surgical radiographs were obtained on average after 4.8 years (SD+/-2.8) and after 9.6 years (SD+/-3.6). A minor mean bone fill of 0.0 mm (SD+/-0.8) for osseous surgery sites and 0.5 mm (SD+/-0.9) for DFDBA sites, was noticed, but this gain was within the margin of measurement errors. Osseous surgery and modified Widman flap procedures with DFDBA resulted in crestal resorption, on average 1.7 mm (SD+/-1.5) and 1.5 mm (SD+/-1.5) and remaining mean defect depth of 2.0 mm (SD+/-1.4) and 2.5 mm (SD+/-1.6), respectively. CONCLUSIONS: Bone changes following bone graft procedures with DFDBA did not differ from those following osseous surgery, and neither procedure resulted in defect resolution with bone fill. It was also concluded that over the study period, stable treatment results were obtained as a result of both osseous surgery and modified Widman flap procedures with adjunct DFDBA.

Analysis of Variance↗
PubMed2000

Treatment of intrabony defects with resorbable materials, non-resorbable materials and flap debridement.

BACKGROUND: Different types of barriers are used in guided tissue regenerative procedures. AIM: This prospective study compared resorbable citric acid ester softened polylactic acid membranes (RM) and non-resorbable expanded polytetrafluoroethylene (ePTFE) barriers (NRM) in GTR treatment of intrabony defects. METHODS: 29 subjects were randomly assigned to the RM group or NRM group. Each patient received one GTR procedure. An open flap debridement (FD) was performed at another site 2 weeks later to evaluate healing potential. Clinical treatment outcomes were finally evaluated 12 months after surgery for changes of pocket depth PD, probing attachment level PAL, and probing bone level PBL, and radiographically for bone change using standardised radiographs. RESULTS: No differences in healing patters after surgery were found between patients in the 2 study groups as evaluated from the FD surgical procedures. NRM treated sites showed less signs of post-surgical inflammation during the 1st 4 weeks of healing than did RM treated sites (p<0.05). GTR-treated defects in the RM group, initially 7.0+/-2.2 mm deep, showed PD reduction of 3.3+/-2.2 mm, PAL gain of 2.4+/-1.8 mm, PBL gain of 2.4+/-3.7 mm (28%) and a radiographic bone fill of 2.3+/-2.4 mm. Defects treated with the NRM exhibited PD reduction of 3.1+/-2.1 mm, PAL gain of 2.4+/-0.8 mm, PBL gain of 2.2+/-1.7 mm (25%) and a radiographic bone fill of 3.3+/-2.2 mm. All improvements were statistically significant (p<0.01) but there was no difference between RM and NRM treatments for any of the efficacy variables. The results of this study indicated that there was no clinically significant difference in treatment outcomes following GTR treatment of intrabony defects with citric acid ester softened polylactic acid membranes as compared to ePTFE barriers. The overall mean inter-proximal vertical bone defect fill at 12 months as assessed from intra-oral radiographs was 44% of the original mean defect depth. CONCLUSIONS: Thus, no clinically significant difference in treatment outcomes was observed following GTR treatment of intrabony defects with citric acid ester softened polylactic acid membranes or ePTFE barriers.

Absorbable Implants↗
PubMed2000

Comparisons of clinical and radiographic measurements of inter-proximal vertical defects before and 1 year after surgical treatments.

BACKGROUND: Radiographic measurements are often used as a substitute for direct clinical measurements requiring re-entry surgery for follow-up outcome studies. AIMS: (1) To assess the reliability of clinical and radiographic measurements of periodontal defects as compared to direct bone measurements during surgical procedures, and (2) to assess the associations between selected clinical and radiographic measurements of periodontal inter-proximal defects. METHODS: 57 inter-proximal periodontal defects were measured at baseline and at 12 months after surgical treatment. Direct measurements during surgery of the distance between the CEJ to the bottom of defects (ABL) were compared with probing to bone (PB), probing attachment level (PAL), and radiographic measurements. RESULTS: Probing to bone is an accurate measure to assess inter-proximal bone level as compared to ABL (mean difference: 0.1 mm) and that intra-oral standardized radiographs underestimate bone level and defect depth by approximately 1.4 mm. The interpretation of periodontal changes between baseline and 12 months after treatment by probing to bone, or PAL measurements, or from radiographic images yield almost identical results (mean difference< or =0.2 mm). For the assessments of changes over time using PB change as the standard, intra-class correlation (ICC) coefficients varied between 0.52 to 0.90. The best ICC coefficient was found for relative attachment level change assessed by the Florida probe (0.90), and with an ICC value of 0.61 for changes assessed from intra-oral radiographs. Two-way analysis of variance failed to demonstrate differences between sets of comparisons. CONCLUSIONS: Both radiographic interpretations of changes over time, and measurements of attachment level changes are reliable in assessing the treatment outcome of inter-proximal intra-bony defects when compared to probing to bone changes as the standard method.

Absorbable Implants↗
PubMed1998

Guided tissue regeneration update.

The ultimate goal of periodontal therapy is to restore periodontal tissues lost through disease or trauma. The most predictable way to accomplish this goal is by guided tissue regeneration (GTR). The principle of GTR is to give preference to certain cells to repopulate the wound area to form a new attachment apparatus. Clinically this is accomplished by placing a barrier over the defect thereby excluding gingival tissues from the wound during early healing. The first generation of GTR barriers were non-resorbable which implies that they have to be removed in a second surgical procedure. Resorbable barriers have recently been introduced, changing GTR into a single-step procedure. Periodontal defects that will predictably benefit from GTR therapy are intrabony, furcation class II and gingival recession defects. This paper reviews the scientific evidence of what can be achieved by GTR procedures for various periodontal defects as well as factors of importance to increase the predictability of a successful treatment outcome.

Absorption↗
PubMed1998

Treatment of intrabony defects by different surgical procedures. A literature review.

This article reviews studies presented during the last 20 years on the surgical treatment of intrabony defects. Treatments include open flap debridement alone (OFD); OFD plus demineralized freeze-dried bone allograft (DFDBA), freeze-dried bone allografts (FDBA), or autogenous bone; and guided tissue regeneration (GTR). The review includes only studies that presented baseline and final data on probing depths, intrabony defect depths as measured during surgery, clinical attachment level (CAL) gain, and/or bone fill. Some reports were case studies and some controlled studies comparing different treatments. In order to assess what can be accomplished in terms of pocket reduction, clinical attachment level gain, and bone fill with the various treatment modalities, data from studies of each treatment category were pooled for meta-analysis in which the data from and power of each study were weighted according to the number of defects treated. In addition, where there were data for each individual defect treated, these were used for simple regression analysis evaluating the influence of intrabony defect depth on treatment outcome in terms of CAL gain and bone fill. This was done in an effort to assess some predictability of the outcome of the various treatments. OFD alone resulted in limited pocket reduction, CAL gain averaged 1.5 mm and bone fill 1.1 mm. Bone fill, but not CAL gain, correlated significantly to the depth of the defect (R=0.3; P < 0.001), but the regression coefficient was only 0.25. OFD plus bone graft resulted in limited pocket reduction. CAL gain and bone fill averaged 2.1 mm. Bone fill showed a somewhat stronger correlation to defect depth than following OFD alone (R=0.43; P < 0.001) with a regression coefficient of 0.37. GTR resulted in significant pocket reduction, CAL gain of 4.2 mm, and bone fill averaging 3.2 mm. CAL gain and bone fill correlated significantly (P < 0.001) to defect depth (R=0.52 and 0.53 respectively) with the largest regression coefficients (0.54 and 0.58 respectively) among the three treatment modalities. By comparing outcomes following the various treatments it became obvious that to benefit from GTR procedures, the intrabony defect has to be at least 4 mm deep.

Alveolar Process↗
PubMed1998

Horizontal alveolar bone loss and vertical bone defects in an adult patient population.

The objectives of the present investigation were to analyze intraoral radiographs and to study 1) the distribution of the distance between the cemento-enamel junction (CEJ) and the alveolar bone level (BL) and 2) the prevalence and severity of vertical defects, and furcation lesions in 416 individuals seeking dental care. Full mouth radiographs were enlarged 7.5 times and the mesial and distal distances between CEJ and bone level were measured. The extent of interradicular molar radiolucencies was also measured. Images of 10,282 teeth were studied. Subjects were between 15 to 94 years (mean age: 47.2, S.D.+/-15.2). On average they had 24.8 teeth (S.D.+/-5.5). The mean distance CEJ-BL increased significantly up to age 45 (r2=0.07; beta=0.29; P < 0.0001) and remained stable thereafter r2=0.09, beta=-0.02, N.S.). The mean distance CEJ-bone level was 1.4 mm (S.D.+/-0.7) in the 15 to 24 age group; 3.0 (S.D.+/-1.5) in the 45 to 54 age group; and 3.02 (S.D.+/-1.4) in the 75 to 94 age group. No vertical defects were found in 163 participants (39.3%); vertical defects > or = 3.0 mm were found in 30.2% (126). Mesial defects were significantly more common that distal defects (P < 0.001). The extent of horizontal bone loss was correlated to extent of vertical defects (r2=0.88; P < 0.0001). The number of remaining teeth was not associated with horizontal or vertical bone loss. In conclusion, the study indicated that few of the individuals had extensive horizontal bone loss. Vertical defects suitable for guided tissue regeneration procedures however, were found in many patients.

Adolescent↗
PubMed1997

Guided tissue regeneration therapy of 203 consecutively treated intrabony defects using a bioabsorbable matrix barrier. Clinical and radiographic findings.

THE AIM OF THIS RETROSPECTIVE three-center study was to evaluate guided tissue regeneration (GTR) therapy in a clinical periodontal setting. The material consisted of 203 consecutively treated intrabony defects > or = 4 mm in 143 patients using a bioabsorbable matrix barrier. Each center followed the same protocol for presurgical, intrasurgical, and follow up examinations. Initial therapy, surgical, and follow-up treatments followed the routine of each center. Treatment was evaluated after 1 year by clinical assessments for probing depth (PD) reduction and clinical attachment level (CAL) gain and by bone fill from computer digitized radiographs. Initial intrabony defect depth averaged 6.3 +/- 1.0 mm clinically and 5.7 +/- 1.8 mm radiographically. Mean PD was reduced from 9.0 +/- 1.0 mm to 3.3 +/- 1.0 mm. Mean CAL gain amounted to 4.8 +/- 1.5 mm corresponding to 79 +/- 13% of the initial intrabony defect depth; 78% of the defects exhibited CAL gain > or = 4 mm. Bone fill averaged 3.2 +2- 1.8 mm. Together with a crestal resorption of 1.1 +/- 1.4 mm this resulted in a defect resolution of 4.3 +/- 1.9 mm or 72%. Forty-seven percent (47%) of the variability in CAL gain could be explained by defect depth, defect width, early barrier exposure, and presence of plaque in the treated area. CAL gain and bone fill were positively correlated to the intrabony defect depth; i.e., the deeper the defect the more the CAL gain and bone fill. Sites with barrier exposure during the first 2 weeks of healing showed significantly less CAL gain than sites at which exposure occurred at a later stage or not at all. Presence of plaque in the treated area had a significant negative impact on both CAL gain and bone fill. It was concluded that GTR-treatment of intrabony defects > or = 4 mm in a periodontal specialist practice will result in clinical attachment level gain and bone fill comparable to what has been demonstrated in case studies and controlled clinical trials. The predictability to obtain CAL gain > or = 4 mm in defects > or = 4 mm was 78%.

Alveolar Bone Loss↗
PubMed1995

The influence of the design of two different bioresorbable barriers on the results of guided tissue regeneration therapy. An intra-individual comparative study in the monkey.

The aim of the present study was to compare two bioresorbable barriers to evaluate whether differences in design influence the result of guided tissue regeneration (GTR) therapy. Twenty-four (24) plaque exposed, recession type defects in 4 monkeys were treated. Contralateral defects were randomized for test or control treatment. During a healing period of 6 weeks, gingival recession resulting in device exposure occurred at 3 test and 10 control sites. One control barrier was exfoliated. Histologically, 9 of the 12 test barriers were completely integrated with the surrounding tissues. At 3 test sites, epithelium had migrated apically outside the barrier to a level not exceeding one-third of the height of the device. Seven of the 11 control barriers were enclosed by dentogingival epithelium. The adjacent connective tissue exhibited local inflammatory cell infiltrates (ICT). At the remaining 4 control sites, the epithelial downgrowth as well as the adjacent ICT areas were limited to the coronal 1/3 of the device. New attachment; i.e., new cementum with inserting collagen fibers, averaged 2.2 mm and 0.8 mm at the test and control sites respectively (P < 0.01). Based on the results of the present study, it was concluded that a bioresorbable GTR device, designed to prevent epithelial downgrowth along the barrier surface, has a higher potential to promote new attachment formation than a device which does not have this property.

Animals↗
PubMed1994

Antenatal cards--what should they contain?

An antenatal card should be designed to facilitate the early detection of important and clearly defined conditions, which in turn can result in well-defined and beneficial actions. The home-based antenatal card is a good instrument for having relevant information accessible at various antenatal visits, and also for transmitting the information to the delivery staff. If properly designed, it could also serve as an important means to assess epidemiological characteristics of the pregnant population, necessary for deciding priorities in a public health perspective. A cross-sectional study of women giving birth in León, Nicaragua, showed that the majority of the women could be classified as high-risk pregnancies. The present paper discusses the design of the Nicaraguan antenatal card, as well as its risk factors. A revision of the antenatal card and the accompanying manual is suggested, particularly with regard to the definitions of the high-risk criteria and the proposed action.

Adolescent↗
PubMed1994

A study of the use of the Nicaraguan antenatal card.

The present study describes the use of a home-based antenatal card in a sample of 120 consecutive women who were giving birth at a large teaching hospital in the city of León, Nicaragua. Information was obtained by interviews with the women before leaving hospital and all data on their antenatal cards and regarding delivery outcome were analysed. Antenatal care attendance by the 120 women was 93 per cent, and 86 per cent had received an antenatal card. However, only in 33 per cent of the cases had the card been adequately used: inappropriate handling in hospital was the commonest cause of non-use. Suggestions for a revision of the card are presented in the companion article, in which we also stress the importance of continuous training of the health personnel.

Adolescent↗
PubMed1994

Clinical use of a bioresorbable matrix barrier in guided tissue regeneration therapy. Case series.

In this case series study 19 Class II furcations and 47 intrabony defects in 59 patients were treated according to the principles of guided tissue regeneration using a bioresorbable matrix barrier. Gingival condition and device exposure were assessed at 2 weeks, and 1, 3, 6, and 12 months after surgery. The effect of therapy was evaluated by assessing probing depths (PD), probing attachment level (PAL), and the position of the gingival margin prior to surgery and 12 months after surgery. Mild clinical signs of inflammation in the soft tissue covering the device was found adjacent to 3 defects only and limited to the first month of healing. Device exposure occurred at 10 out of the 66 defects. At the furcation defects, the mean PD reduction amounted to 3.7 mm (P < or = 0.001). Mean gain PAL vertical was 3.4 mm and PAL horizontal 3.3 mm (P < or = 0.001), resulting in complete closure of 9 out of the 19 defects. Mean gingival recession was 0.2 mm. At the intrabony defects mean PD reduction was 5.4 mm and mean gain of PAL 4.9 mm (P < or = 0.001). Gingival recession averaged 0.5 mm (P < or = 0.05). It was concluded that the use of the matrix barrier in GTR therapy resulted in 1) reduced probing depths; 2) pronounced gain of clinical attachment; and 3) a very low incidence of gingival pathology, gingival recession, and device exposure.

Adult↗
PubMed1994

Guided tissue regeneration using a bioresorbable matrix barrier.

Bioresorbable barrier material, used in guided tissue regeneration, changes the conventional two-stage surgery to a single-step procedure. This article presents a general surgical protocol for application of a bioresorbable matrix barrier (Guidor AB, Huddinge, Sweden). Three case reports are used to illustrate the surgical treatment of a Class II furcation defect, an intrabony defect, and a recession type defect. The learning objective of this article is to enhance the knowledge of surgical procedures and bioresorbable barrier membranes available.

Adult↗
PubMed1994

Periodontal tissue response to a new bioresorbable guided tissue regeneration device: a longitudinal study in monkeys.

This study evaluated periodontal tissue response to a new bioresorbable guided tissue regeneration barrier material following guided tissue regeneration treatment of dehiscence-type defects at 45 teeth in 15 monkeys. The results were clinically and histologically evaluated 6 weeks and 3,6, 12, and 24 months posttreatment. Healing was uneventful and without inflammation or other adverse tissue reactions. Following 6 weeks of healing, the matrix barrier was completely integrated with the surrounding tissues, preventing epithelial downgrowth along the device. There were no inflammatory cell infiltrates adjacent to the material. New attachment (ie, new cementum with inserting collagen fibers) and new supporting bone were found after 6 weeks of healing. The matrix barrier maintained its functional stability for a minimum of 6 weeks. The subsequent slow resorption process of the material occurred without detrimental effects on the surrounding tissues, demonstrating the biocompatibility of the material. The material was completely resorbed after 6 to 12 months. At the final stages of the resorption process, macrophages and multinuclear cells were present within the tissue that replaced the material. The design and the resorption pattern of the matrix barrier are discussed in relation to the regenerative wound healing process.

Animals↗
PubMed1992

Influence of occlusion on posterior cantilevers.

The incorporation of posterior two-unit cantilevers in fixed prosthodontics is generally discouraged because of the assumption that large posterior chewing and biting forces might jeopardize the prosthesis and the abutment teeth. This investigation was performed to study (1) the distribution of chewing and closing forces in dentitions with cross-arch bilateral posterior two-unit cantilever fixed partial dentures and (2) the influence of different occlusal arrangements on the magnitude of these forces along the cantilever segments. Six patients were included in the study. Axially directed closing and chewing forces were measured with miniature transducers bilaterally mounted in pontic units anteriorly and in each of the four cantilever units. In ideal occlusion, occlusal forces decreased considerably along the cantilever segments in the distal direction. Infraoccluding the distal cantilever unit by 80 microns had little influence on the magnitude of the initially small local force in this region, whereas an 80 microns high primary occlusal contact considerably increased the local force over the distal cantilever unit. The clinical implications of the results are discussed.

Acrylic Resins↗
PubMed1992

Frequency distribution of individuals aged 20-70 years according to severity of periodontal disease experience in 1973 and 1983.

The aim of this study was to compare changes in periodontal status of a Swedish population over a 10-year period expressed as frequency distributions of individuals according to severity of periodontal disease experience. The study involved 600 randomly selected individuals evenly distributed into age groups 20, 30, 40, 50, 60 and 70 years, examined in 1973 and another randomly selected group of 597 individuals similarly age distributed and examined in 1983. Based on clinical data and full mouth intraoral radiographs all individuals were classified into 5 groups according to severity of periodontal disease experience. In 1983, 23% of the individuals were classified as having healthy periodontal tissues, group 1, compared to 8% in 1973. The changes were most pronounced in the age groups 20 and 30 years, among whom 58% and 35%, respectively, were registered as having healthy periodontium in 1983. The prevalence of individuals with gingivitis without signs of lowered periodontal bone level, group 2, was 22% in 1983 compared to 41% in 1973. In all, 49% of the dentate population in 1973 and 45% in 1983 showed no marginal alveolar bone loss. Moderate periodontal bone loss, group 3, was found in 41% of the population in 1983 compared to 47% in 1973. Among 30-, 40-, and 50-year-olds, there were more, and among 60- and 70-year-olds, fewer individuals in this group in 1983 compared to 1973. 96% of the dentate population were classified as belonging to groups 1, 2 or 3 in 1973 compared to 86% in 1983.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗