Differential diagnosis and treatment strategies for biologic complications and failing oral implants: a review of the literature.

The aim of this article was to review the literature on differential diagnosis and treatment of biologic complications and failing implants. All types of publications, with the exception of abstracts, published in English up to December 1998, were included. A multi-layered search strategy was used. Controlled clinical trials (CCTs) were searched in the Cochrane Oral Health Group's Specialized Register of Trials. This database contains all CCTs identified in MEDLINE and EMBASE. PubMed was searched using various key words and the "related articles" feature. All identified publications were obtained and none were excluded. Infection, impaired healing, and overload are considered the major etiologic factors for the loss of oral implants. Only a few clinical and animal investigations were found that tested the validity of the proposed therapeutic approaches. The treatment of failing implants is still based mainly on empirical considerations, often derived from periodontal research, from data extrapolated from in vitro findings, or from anecdotal case reports performed on a trial-and-error basis.     

A comparative analysis of maxillary tooth movement produced by cervical headgear and pend-x appliance

The purpose of this study was to compare the effects of cervical headgear and pend-x on the maxillary first molar, second molar, first premolar, and upper incisors. Cephalometric radiographs were obtained at the start of treatment (T1) and after molar distalization was completed (T2) for 13 patients in a pend-x group and 13 patients in a cervical headgear group. The changes of the maxillary teeth were measured on maxillary superimpositions. Nonparametric Mann-Whitney U-test was used to compare the mean differences between the two groups. The mean amount of distalization for the headgear group was 3.15 +/- 1.94 mm and that for the pend-x group was 3.81 +/- 2.25 mm. The second molar teeth were also distalized to a mean amount of 2.27 +/- 1.33 mm in the headgear group and 2.04 +/- 2.15 mm in the pend-x group. The mean treatment time for distalization was 11.38 +/- 3.18 months for the headgear group and 7.31 +/- 4.09 months for the pend-x group. During distalization, the maxillary molars tipped distally in both groups, but intergroup differences were not significant. The anterior inclinations of the first premolar and upper incisor increased significantly in the pend-x group (P < .01). Maxillary molars showed no vertical movement in the pend-x group but extruded in the headgear group (P < .01). The anchorage loss of the pend-x appliance as well as the necessary patient compliance and greater treatment time with the cervical headgear should be taken into consideration.     

Effect of food-simulating liquids on the flexural strength of composite and polyacid-modified composite restoratives

This study investigates the effects of food-simulating liquids on composite and polyacid-modified composite restoratives. Three composite (Z100, Spectrum TPH, and Tetric Ceram) and three polyacid-modified composite (F2000, Dyract AP, and Compoglass) restoratives from the same manufacturers were selected for the study. Flexural strength specimens (25 x 2 x 2 mm) based on ISO 4049 specifications were fabricated according to the manufacturers recommendations. After light polymerization, the specimens were removed from their molds and conditioned for one week at 37 degrees C in the following mediums: (1) deionized water, (2) 0.02 M citric acid, (3) heptane, and (4) 50% ethanol-water solution. Specimens stored in air were used as controls. The sample size was five for each material-medium combination. After conditioning, the specimens were blotted dry, measured, and subjected to flexural strength testing using an Instron Universal Testing Machine with a crosshead speed of 0.05 mm/minute. With the exception of Compoglass, flexural strength of all restoratives after conditioning in heptane was significantly greater than that after conditioning in all other mediums and the control. Although no significant difference in flexural strength values was observed between the different restoratives when the materials were conditioned in heptane or air (control), significant differences were observed between the different restoratives after conditioning in aqueous solutions (water, citric acid, and ethanol-water solution). The flexural strengths of the composites were generally significantly higher than their polyacid-modified counterparts after conditioning in the various aqueous solutions. The detrimental effects of aqueous solutions on flexural strength appeared to be greater with polyacid-modified composite resins than with composite restoratives.     

The efficacy of a single pocket irrigation on subgingival microbial vitality

The object of this study was to monitor the proportion of vital bacteria (microbial vitality: VF in %) present in subgingival dental plaque following one single subgingival irrigation with saline (S), chlorhexidine (CHX) or povidone iodine (I₂), but without any subgingival instrumentation. Its effect on the main composition of the microflora was also assessed. Seventeen patients with adult periodontitis took part in this investigation. In each patient four initially untreated pockets (pocket depth 5–11 mm) associated with bleeding were selected for the standardised pocket irrigation and plaque sampling at baseline (0 h) and after the following 1 h, 24 h, 7 days and 31 days. The subgingival irrigation was only performed once (0 h). One pocket per quadrant was irrigated using 0.9% prereduced S, 0.2% CHX or 0.05% I₂ (Iso-Betadine Buccale). The remaining untreated pocket without any irrigation served as an additional control (C). Using an acrylic splint as a guide, paperpoints were inserted into the pocket precisely at the same site to collect subgingival plaque. The bleeding on sampling (BOS) was thereafter noted. The proportions of bacterial morphotypes were examined by darkfield microscopy. VF was evaluated using a vital fluorescence staining. The undisturbed subgingival dental plaque was composed of 86% (median value) vital bacteria. The sampling procedure alone and the saline irrigation led to a decrease in the number of spirochetes but had no influence on the vitality of the flora. Large variations in VF could be observed in the short-term (1 h, 24 h) irrigation effect of CHX and I₂. The reduction of VF was still significant after 7 days (VF_CHX 30–80%, VF_I2 35–80%) but persisted up to 31 days only after I₂ irrigation (VF_I2 12–90%). The findings indicated that all single subgingival irrigations resulted in a temporary change of the subgingival microflora while povidone iodine produced the longest lasting antimicrobial effect. Any clinical advantage of this situation should be further investigated. Received: 16 February 1998 / Accepted: 29 May 1998     

Occurrence of Prevotella intermedia and Prevotella nigrescens in relation to gingivitis and gingival health

AIM: The occurrence of Prevotella intermedia (Pi) and Prevotella nigrescens (Pn) in relation to natural gingivitis, gingival health and 14-day experimental gingivitis was investigated in 25 non-dental students. MATERIALS AND METHODS: Samples were taken from the dorsum of the tongue, the tonsils (or tonsillar area), and the supra- and subgingival plaque. RESULTS: The microbiological results show that 73% of the samples were positive for the bacterial species presumed to be Pi and/or Pn. In natural gingivitis, gingival health and in experimental gingivitis 25, 23 and 25 subjects were found to be positive for Pi and/or Pn, respectively. The results of the 889 isolates that were successfully purified and differentiated, show that almost all subjects were colonized with Pn whereas approximately half of the study population harboured Pi. These 2 species were isolated from both dental plaque and mucosal sites and were found to colonize the oral cavity simultaneously. CONCLUSION: In natural gingivitis, at the start and after 14 days of experimental gingivitis, Pn was the predominant micro-organism.     

Quality-specific taste impairment following the application of chlorhexidine digluconate mouthrinses

Although chlorhexidine has been widely used in the prevention and treatment of gingivitis, its effects on taste sensation have not been well studied. The purpose of the present study was to evaluate taste alterations following regular applications of 0.2% chlorhexidine mouthrinses. 24 healthy and non-smoking clinical instructors, dental assistants and dental students were divided into 3 groups after having reached a status of clinical gingival health by 4 weeks of supervised oral hygiene procedures. Following this, they were asked to abolish all mechanical oral hygiene for a period of 14 days, during which time they rinsed twice daily with different mouthrinses. Group A rinsed with a 0.2% chlorhexidine solution, group B served as control and utilized a 0.001 molar solution of quinine hydrochloride as a placebo rinse. A second control group (C) rinsed with distilled water. At days -3 and -2, as well as at days 1, 2, 13 and 14 of the experimental period, and 1 and 2 days after cessation of the rinsing, taste sensitivity was evaluated by a magnitude estimation, suprathreshold scaling procedure for the 4 taste qualities--sweet, salty, sour and bitter. 6 different concentrations of each of sucrose, sodium chloride, citric acid and quinine hydrochloride were utilized. Magnitude estimations of the perceived intensities of each series of test solutions were calculated. The analysis of co-variance revealed significant differences at the short-term and treatment-related suprathreshold scaling responses between both control groups (B, C) and the test group (A) for the sodium chloride magnitude estimation function. However, no significant inter-group differences in the magnitude estimation function were found for the remaining taste qualities.(ABSTRACT TRUNCATED AT 250 WORDS)     

A long-term study of 370 autotransplanted premolars. Part II. Tooth survival and pulp healing subsequent to transplantation

The purpose of the present investigation was to determine the long-term prognosis of autotransplanted premolars with respect to tooth survival and pulpal healing. The material consisted of 195 patients aged 7 to 35 years, with a total of 370 autotransplanted premolars with observation period ranged from 1 to 13 years. Teeth transplanted with incomplete and complete root formation showed 95 per cent and 98 per cent long-term survival respectively: Pulp healing as evaluated by sensibility testing and radiographic signs of partial pulp canal obliteration was usually verified 6 months after transplantation. The frequency of pulpal healing (versus pulp necrosis), appeared to be closely related to stage of root development at time of transplantation. Teeth transplanted with incomplete and complete root formation showed 96 per cent and 15 per cent pulp healing respectively. Another and associated factor which could equally well predict pulpal healing was the diameter of the apical foramen of the graft. Finally, in teeth with completed root formation, the use of bursa with internal cooling and no extra-alveolar storage prior to transplantation seemed to increase the chance for pulpal healing. The present study indicates, that the size of the apical foramen and possibly the avoidance of bacterial contamination during the surgical procedure are explanatory factors for pulpal healing.     

Introduction of a new periodontal probe: the pressure probe

Abstract. A new periodontal probe has been developed: the pressure probe. The probe consists of a cylinder and piston assembly connected to a variable air pressure system. The working end is a metal tube in which a plunger can move freely. By means of air pressure the plunger is constantly fully extruded. During probing the plunger will intrude from the position of maximum extrusion only as the probing force exceeds the predetemined force acting on the plunger. The difference by which the plunger is intruded can be read on a millimeter scale within the handle of the probe. The purpose of the present investigation was to determine whether probing force is constant during probing, to study the reliability of reading pocket depth measurements in vitro, and to investigate the relationship between pocket depth and applied force in man. In order to evaluate whether the probing force is constant during probing, measurements were performed on a force transducer. Results show that the device makes probing possible with a constant and adjustable pressure. The influence of the reading of the calibration on pocket depth assessment in vitro was studied in an in vitro model. Results show that pocket depths of 1 mm to 8 mm ± 0.25 mm were read correctly in about 90 % of instances. Generally about 45 % of the half millimeter values were recorded as the lower whole millimeter. To investigate the relationship between pocket depth and applied force, 173 pocket depth measurements were performed in eight patients. Patients selected for this study had, in some part of the upper anterior segment, loss of alveolar bone support up to two-thirds of the root length, visible on periapical radiographs. All patients received preliminary treatment consisting of plaque control and removal of subgingival deposits. The mean Sulcus Bleeding index score was 0.2. Pocket depth measurements were carried out with forces of 0.15, 0.25, 0.50 and 0.75 N. Both approximal and vestibular pocket depths were recorded. In this study 0.75 N was chosen as the maximal force since in a pilot study a force of 1.0 N appeared too painful for patients. Results show an increasing pocket depth with increasing probing force. The mean pocket depths increased from 2.08 mm at 0.15 N to 3.71 mm at 0.75 N. Testing showed it to be statistically significant. At 0.75 N, 72 out of the 173 pockets examined were equal to or deeper than 4 mm. The percentages were calculated of differences equal to or more than 2 mm between pocket depth measurements carried out with 0.75 N and lower forces. It was found that 63.3 % of pocket depths measured with 0.15 N were, when measured with 0.75 N, 2 mm or more deeper. This was 43.1 % when 0.25 N and 0.75 N were compared and 9.7 % when 0.50 N and 0.75 N were compared. The maximal differences varied from 5 mm to 7 mm.     

A Longitudinal Survey for Genome-based Identification of SARS-CoV-2 in Sewage Water in Selected Lockdown Areas of Lahore City,Pakistan: A Potential Approach for Future Smart Lockdown Strategy

In 2019, the newly emerged SARS-CoV-2 virus caused pneumonia-like illness. The disease rapidly spread globally, leading to a worldwide outbreak referred to as the COVID-19 pandemic. The affected patients show symptoms of fever, dry cough, respiratory distress, myalgia, and gastrointestinal disturbance. As of April 5, 2021, 132,083,022 people worldwide were affected by COVID-19, while 2,868,454 people died due to the disease[1]. SARS-CoV-2-positive patients may remain asymptomatic or start showing symptoms in 2?14 days after exposure to the virus[2]. The viral infection can be diagnosed from nasopharyngeal, throat, alveolar lavage, lacrimal, blood, and stool samples. The patient starts shedding the virus in stool regardless of being symptomatic or asymptomatic, which makes sewage-based detection of the virus to be more beneficial in the early infection stage.