Author Archives: Master Theses UMCG

Background: Early diagnosis of Medium-Chain Acyl-Coenzyme A Dehydrogenase (MCAD) deficiency through neonatal bloodspot screening (NBS) and treatment significantly reduce morbidity and mortality. However, the NBS also detects false-positives (FP) as well as patients with ‘mild’ MCAD deficiency. In this study we investigated whether additional parameters could optimize the Dutch NBS, reduce FP and differentiate between severe and ‘mild’ MCAD deficiency.
Methods: A retrospective study of the NBS protocol detecting MCAD deficiency in the Dutch birth cohort between 2007-2015 was performed. The screening parameters C8, C6, C10, C10:1 and ratios C8/C10 and C8/C2 were evaluated in relation to genotypes and MCAD enzyme activity. In this study ‘mild’ MCAD deficiency was defined by ‘variant’ genotypes (genotypes that had not been identified in patients with clinical symptomatology) and/or high residual MCAD enzyme activity (≥10% measured in lymphocytes or leukocytes).
Results: 194 MCAD-deficient patients were identified in this study, of which 189 were detected through NBS. The prevalence of MCAD deficiency was 1/8,288 (95% CI: 1/7,265 – 1/9,645). The C8-cut-off showed a 99% sensitivity and approximately 100% specificity. The ratios C8/C10 and C8/C2 also correlated strongly with MCAD deficiency and combining the three parameters reduces the number of FP with 70%, at the expense of 22% of the ‘mild’ MCAD deficient patients. The C8/C10-ratio differentiated better than C8 and C8/C2 between severe and ‘mild’ MCAD deficiency.
Conclusion: This study confirms that the primary screening marker C8 is extremely effective to detect MCAD deficiency. Though, adding the ratios C8/C10 and C8/C2 would further improve the NBS protocol. Continue reading →

Urinary exosomes (EXO) are lipid membrane bound structures that mediate intercellular signaling through the transfer of proteins, miRNA and other factors. Kidney injury molecule 1 (KIM-1) acts as a phosphatidylserine (PS) receptor, inducing the uptake… Continue reading →

Introduction – The prostate-specific antigen (PSA) test has been widely introduced in the nineties. The use of the test as a screening method for prostate cancer is highly debated worldwide. Advocates argue that the PSA test allows for early detection… Continue reading →

Background. The frailty syndrome is considered to be the most problematic expression of ageing. One of the underlying causes is a gradual decline in muscle mass and muscle strength. In the screening for patients at risk, standardization of the measurement instruments of loss of muscle is essential.
Objectives. This study aimed to measure muscle mass and muscle strength in elderly in order to correlate existing measurement instrument tools to each other. The second objective is to measure and correlate muscle density and muscle strength in elderly.
Design and setting. This prospective observational study included patients of 70 years and above visiting the outpatient clinic of the Gelre Hospital in Apeldoorn to undergo a Computed Tomography (CT) scan of the abdomen (January-April 2016). Muscle mass was calculated by Total Psoas Area (TPA). Muscle strength was measured by hand grip strength (GS). In pa-tients with identical amount of contrast fluid, muscle density was measured using the Houns-field Unit Average Calculation (HUAC).
Results. A total of 175 patients (median age 76 years) was included. After correction for con-founding factors (age, gender, and frail state) GS and TPA remained significantly correlated (R²=0.43, P=0.001). GS and HUAC were not significantly correlated (P=0.46 for men and P=0.39 for women). Influence of contrast fluid on HUAC was observed.
Conclusion. Although muscle strength (GS) and muscle mass (TPA) are correlated, they each symbolize different aspects of a patient’s physical condition. Muscle density (HUAC) is not correlated with muscle strength. Continue reading →

Introduction: Failure rates of the so called undisplaced femoral neck fractures (FNF) vary from 4-23%. Literature states that undisplaced FNF always should be treated by internal fixation. The classification in undisplaced and displaced FNF is most commonly performed by the Garden classification. This classification is solely based upon the AP radiographs. Consequently the tilting of the femoral head in the anterior and posterior direction is not included in this classification. Over the years there have been many studies to identify pre- and post-operative predicators for failure. Yet posterior tilt, also known as retroversion or anterior angulation, of the femoral head as a predictor is only described by several authors. This study investigates two different methods to measure posterior tilt of the femoral head and its influence on the failure rate of undisplaced FNF.
Patients and methods: The posterior tilt of 164 undisplaced FNF treated by Gannet osteosynthesis were measured on the lateral X-ray of the hip using the Lateral Garden Angle (LGA) and the Posterior Tilt Measurement (PTM). Correlation between posterior tilt of the femoral head and the failure rate after Gannet osteosynthesis was assessed. Furthermore an intra- and inter observer reliability study was done with the two different methods to assess the validity of these measure methods.
Results: The overall failure rate was 5.5%. No correlation could be found between the posterior tilt of the femoral head and the failure rate if it was measured according to the LGA (P=0.366). If the posterior tilt was measured using the PTM a larger angle was associated with a higher failure rate (P=0.030). Retroversion of ≥20° measured using PTM is associated with a 4 times higher failure rate (OR = 4.286 (CI 95% 1.092 – 16.826) (P-value = 0.037)). The intra and inter observer reliability of the LGA was 0.765 and 0.601(P Continue reading →

SUMMARY
INTRODUCTION
Acute respiratory distress syndrome (ARDS) is characterized by hypoxemic respiratory failure following an either direct (e.g. pneumonia) or indirect (e.g. sepsis) pulmonary insult. Dealing with hypoxemia remains the major challenge at bedside and is currently approached with lung-protective mechanical ventilation since specific treatment targeting the pathogenesis of ARDS is lacking.
Pathological hallmarks of ARDS are uncontrolled inflammation and coagulation leading to alveolar and interstitial edema, as well as infiltration of inflammatory cells in the alveolar space. Various cytokines, proteases and their inhibitors play a pivotal role in modulation of inflammation. Recent evidence suggests that proteinase inhibitors antithrombin (AT) and α1-protease-inhibitor (A1PI), may exert anti-inflammatory, anti-coagulant and immunomodulatory properties and may even have synergistic beneficial effect in diminishing inflammation. We hypothesize that combination therapy of AT and A1PI (COMBO therapy) has beneficial effect on lung damage and inflammatory markers in a murine model of direct acute lung injury.
METHODS
Balb/c mice (n=44) received 5 mg/kg LPS (E. Coli, 0127:B8) intranasally (i.n.) simulating direct acute lung injury (T=0). One hour later (T=1) the intervention drugs AT, A1PI only and COMBO therapy were administered intraperitoneally (i.p.) and at T=6 all mice were sacrificed. State of inflammation was determined using Luminex to quantify levels of inflammatory markers TNFα, IL-1β, IL-6, KC and IL-10 in plasma and bronchoalveolar fluid (BALF), and assessing total protein levels and neutrophil influx in BALF.
RESULTS
Intranasal LPS administration induced lung injury, evidenced by markedly increased levels of TNF-α and IL-1β in BALF and increased vascular permeability in all intervention groups and the control group compared to the vehicle group (P Continue reading →

Introduction: Over the past five decades there has been a shift from mandatory operative
exploration to selective non-operative management (SNOM) in penetrating abdominal
trauma(PAT). Besides all the proven benefits of SNOM, the main concern is the po… Continue reading →

Background
Potassium derangements are associated with increased mortality at the intensive care unit
(ICU). This study hypothesizes that increased renal loss of potassium plays a role in the
development of potassium derangements in patients with traumatic brain injury who received
thiopental to induce barbiturate coma (Study A) and in patients who were cooled to
therapeutic hypothermia (TH, 33°C) or therapeutic normothermia (TN, 36°C) following an
out-of-hospital cardiac arrest (OHCA) (Study B).
Methods
A single-centre retrospective study was performed. Serum potassium levels were used to
determine the incidence of potassium derangements. Potassium balances were calculated from
potassium intake and potassium excretion. In Study A three phases were compared; before,
during and after thiopental infusion. In Study B the hypothermia/normothermia phase
(HT/NT phase) consisted of two calendar days after admission. The post-HT/NT phase
consisted of two calendar days following cessation of the HT/NT phase.
Results
Five patients were included in Study A and 34 patients in Study B (n=16 for TH, n=18 for
TN). In Study A, the incidence of hypokalemia was higher during thiopental infusion
compared to before and after therapy, respectively, 100%, 60% and 25% (P=0.03). There
were no significant differences between potassium balances during thiopental therapy
compared to before and after therapy. In Study B, median cumulative potassium
administration during the HT/NT phase was 112 (IQR, 65 to 142) mmol in the TH group
compared to 36 (IQR, 25 to 54) mmol in the TN group (P Continue reading →

Probleem- en doelstelling
Erosieve gebitsslijtage is een veel voorkomend verschijnsel onder de gehele Nederlandse bevolking. Bij jongvolwassenen zijn vaak al tekenen van deze slijtage te zien. Het is niet duidelijk of jongvolwassenen kennis hebben van erosieve gebitslijtage.
Dit onderzoek heeft als doel inzicht te verkrijgen in de mate van kennis over erosieve gebitsslijtage door jongvolwassenen. Tevens is beoogd inzicht te verkrijgen in de gewenste manier van het overbrengen van tandheelkundige informatie op jongvolwassenen.
Materiaal en methoden
Dit onderzoek is opgezet binnen het project van “Tandheelkundig Onderzoek en Praktijk Noord Nederland” (TOP-NN project). Aan het onderzoek hebben 25 praktijken deelgenomen. In het onderzoek zijn vragenlijsten ingevuld door jongvolwassen (20 t/m 25 jaar) tandartsbezoekers. In totaal zijn er 331 vragenlijsten geïncludeerd. De vragenlijst bevat vragen over een drietal onderdelen, namelijk de achtergrond van de deelnemer, de kennis omtrent erosieve gebitsslijtage en hoe de deelnemer tandheelkundige informatie wenst te ontvangen.
Op basis van de juiste antwoorden op de vragen naar de kennis over erosieve gebitsslijtage is een kennisscore opgesteld. De maximaal te behalen kennisscore was 24 punten.
De intraclass correlatie (ICC) voor de deelnemers in de mondzorgpraktijken was nul, dit houdt in dat de kennisscore erosieve gebitsslijtage van de jongvolwassenen onafhankelijk is van de mondzorgpraktijken waartoe zij behoren. Statistische toetsing is uitgevoerd met behulp van de Mann-Whitney U test, de Kruskal Wallis test en een lineaire regressie analyse.
Resultaten
De mediane kennisscore is 16 punten en de 25%-75% kennisscores zijn 13-18 punten. Vragen die vaak juist zijn beantwoord (88-97% juist) gingen over de erosieve aspecten van cola, energiedranken, vruchtensappen en sportdrank. Tevens zijn de niet-erosieve aspecten van water en mineraalwater (resp. 97% en 91% juist) ook bij veel jongvolwassenen bekend. De vragen die door minder dan de helft (9-44%) van de jongvolwassenen goed zijn beantwoord gaan over de gevolgen van erosieve gebitsslijtage, het effect van een droge mond, effect van water drinken direct na een zuurmoment, het niet-erosieve effect van yoghurt en het aantal eet- en drinkmomenten op een dag. Het aantal eet- en drinkmomenten op een dag is slechts door 9% van de deelnemers juist beantwoord.
De lineaire regressie analyse toont een significante mate van samenhang tussen de behaalde kennisscore en twee predictoren, namelijk een hoog opleidingsniveau en een deelnemer die eerder informatie over tandslijtage heeft ontvangen van zijn tandarts of mondhygiënist scoren hoger.
De meeste jongvolwassenen (67%) zoeken zelf niet naar tandheelkundige informatie. Als de jongvolwassenen wel willen zoeken naar tandheelkundige informatie dan geven zij de voorkeur aan dit te doen via een internetzoekmachine (80%) of door het te vragen aan de tandarts (56%).
De jongvolwassenen ontvangen het liefste tandheelkundige informatie door middel van een gesprek (81%), een folder (39%) of een e-mail (28%). Hierbij konden meerdere antwoorden worden aangekruist. De combinatie van een gesprek met een folder of e-mail is vaak gekozen.
Tevens geven de jongvolwassenen aan de informatie het beste te kunnen onthouden wanneer het hen wordt verteld (71%) of wanneer ze het kunnen lezen (51%). Ook hierbij konden meerdere antwoorden worden aangekruist. De combinatie van verteld worden en kunnen lezen veel gekozen.
Slechts 8% van de jongvolwassenen geeft aan tandheelkundige informatie te willen ontvangen door het aanraden van een app. Bij het zelf zoeken naar tandheelkundige informatie geeft 2% aan dit via de app van het Ivoren Kruis te doen en 3% geeft aan een andere app te gebruiken hiervoor.
Conclusie
De jongvolwassenen weten nog lang niet alles over erosieve gebitsslijtage. Het maximale aantal eet- en drinkmomenten is bij bijna niemand bekend. Hoog opgeleiden en jongvolwassenen die al eerder tandheelkundige informatie over erosieve gebitsslijtage hebben ontvangen hebben een significant hogere kennisscore.
De jongvolwassenen wensen te worden geïnformeerd door een gesprek met de mondzorgprofessional in combinatie met een folder of een e-mail. Het aanraden van een app is niet zinvol.
Voor het verhogen van de tandheelkundige kennis onder jongvolwassenen zal individuele mondelinge voorlichting ondersteund met schriftelijke informatie nodig zijn. Het ontwikkelen van effectieve individuele schriftelijke ondersteuning met extra aandacht voor de lager opgeleiden kan een volgende stap zijn tegen erosieve gebitsslijtage. Continue reading →

Objectives
The aim of this study is to determine the success of endodontic treatment in a specialised en-dodontic practice and to identify factors predicting that success.
Method
In this study, the success rate of endodontically treated teeth was dete… Continue reading →

OBJECTIVE: The aim of this randomized controlled trial was to assess the 10-year effects of three different augmentation techniques for implant supported restorations in the maxillary aesthetic region regarding clinical and radiographic parameters, and patient-centred outcomes.
MATERIAL AND METHODS: Ninety-three patients requesting single tooth replacement and presenting with a horizontal bone deficiency were included. After augmentation, 93 ITIEstheticPlus implants were placed. Clinical variables, standardised radiographs and
photographs and patient questionnaires were analysed to assess the impact of the various augmentation techniques 1 month (T1), 12 months (T12) and 120 months (T120) after final crown placement.
RESULTS: 10-years implant survival was 95.7% and did not differ between the groups neither were significant differences observed in the other treatment outcomes assessed. Peri-implant bone loss was low, viz. 0.48±1.19 mm (mesial) and 0.30±1.24 mm (distal) at T120. Loss of midbuccal marginal gingival level at T120 was 0.32±0.83 mm. Mean overall satisfaction at T120 was 8.6 with 98.6% of the patients satisfied.
CONCLUSION: Clinical, radiographic, aesthetic and patient centred outcomes were very
favourable after 10 years and did not differ between the groups with different bone
augmentation techniques. Continue reading →

Aim: The occlusal splint is an appliance used to influence the signs and symptoms of
temporomandibular dysfunction (TMD) and to protect the teeth from excessive wear due to
bruxism. There is no consensus in the literature about the therapeutic effect of occlusal splints,
however there is agreement on the behaviour changing effect. The explanation for this is that
because of the patients’ anticipation on the outcome of the intervention buxism decreases. This
underlines the importance of a well-fitting splint. The occlusal appliance can be manufactured
in a conventional way as by digital designing and thereafter milling the splint out of acrylic
resin. The aim of this study is to find out which method leads to a better result.
Materials and method: This study is a doubleblind randomised pilot study. The study
population was, after exclusion, a group of 34 dental students aged 20-35 years old. With these
students, alginate impressions of the upper and lower arch were made, as well as a wax bite in
maximal occlusion decreasing the vertical overbite with a minimum of 2,5 mm. One half of the
group received a conventionally manufactured splint without button anchors and the other half
received a digitally designed and milled splint. Both types of splint were of the Michigan type
with canine guidance. Research was done on the stone models, during the phase in which the
splints were placed and during a digital bite registration. The variables that have been measured
are occlusion, articulation, fit, retention and wear comfort. The programs R and IBM SPSS
were used to compare these variables in the study groups for statistical significance. In this
study a 95% confidence interval was chosen.
Results: A statistically significant difference between the two types of splint was found
in the variables fit ((U=84,000; p=0,036) and retention (p=0,001), both measured on the stone
models. In addition to that, a statistically significant difference was found in the retention
judged by the study population (p=0,01346) and the number of occlusal contact points in the
anterior region measured by the T-scan (U=78,000; p=0,020). All these mentioned differences
were in favor of the digitally designed splints. The variable occlusion in this study is subdivided
in ‘symmetrical contact between the left and the right side of the splint’, ‘the number of occlusal
contact points left and right on the splint’ and ‘simultaneous and evenly contact when coming
in occlusion’. The first two mentioned variables were measured with both articulating paper
and the T-scan and the last one mentioned was judged by the study population. Despite the fact
that no significant difference was found in the first two mentioned variables, the digitally
designed splints scored better on average than the conventionally manufactured splints which
shows a trend. This was also the case for the ‘wear comfort’ although both types of splint scored
low. This trend was not seen in the variables ‘articulation’ and ‘distribution of the bite force
measured by the T-scan’ and ‘simultaneous and evenly contact when coming in occlusion’.
Discussion and conclusion: The digitally designed and manufactured occlusal splint
scored, in most of the researched variables, better on average than the conventionally
manufactured splint. In a couple of cases this difference was also found to be statistically
significant. One can consequently say that there is a tendency in favour of the digitally
designing and manufacturing way of producing an occlusal splint. Continue reading →

Summary
Background Most of the Dutch youth has dental caries or have had any experience
with it. There are several treatment options when the disease is no longer under control by the
patient. Most of those treatment seem very difficult because the child is in pain, is not yet
accustomed to visiting a dentist and the treatment of young children with extensive problems
is perceived as difficult by the dentist. There needs to be a treatment method that is quick and
easy to use but relieves the patients of the pain caused by dental caries. The treatment method
in which the lesion is covered with GC Fuji Triage® without giving local anaesthesia,
preparation or excavation in combination with giving instructions to the patient and regular
fluoride application could be a method that meets the objections inherent in the more invasive
treatment methods. However, it’s unclear whether the tooth can exfoliate without interference,
whether other treatment options can be explored when there is failure, whether this method is
applicable to both occlusal and approximal lesions and whether it is applicable to both
shallow and deep carious lesions.
Methods The study material was obtained from anonymous clinical records of children
with carious lesions covered with glass ionomer GC Fuji Triage® treated in referral practice
for Pediatric Dentistry in Ermelo. 140 patients enrolled in this study, a total of 690 carious
deciduous teeth were treated with GC Fuji Triage®. The following variables were measured
with each deciduous tooth: the survival (whether the coverage of the carious laesion
persevered until exfoliation), the location and depth (X-score) of the lesion and the total
duration that GC Fuji Triage® functioned as a hedge of the carious lesion. Finally, the raison
for failure was documented (minor or major failure). The data was analysed using IBM SPSS
Statistics 23.
Results Survival of deciduous teeth which are covered with GC Fuji Triage is
79,3%. 9,3% experienced minor failure, 11,4% major failure. The survival of occlusal lesions
(89,3%) is higher than the survival of approximal lesions (67,4%) and a higher survival rates
is seen at the lower X-ray scores (X-score 3: 83,5%, X-score 4: 61,5%, X-score 5 37,5%). In
premature failure of GC Fuji Triage® 9,3% of the deciduous teeth had a conventional
restoration or got a Hall-crown (minor failure). 11,4% of the deciduous teeth were extracted
(major failure).
Conclusion The treatment method of the disease caries in which a lesion is covered
with GC Fuji Triage® without without giving local anaesthesia, preparation or excavation in
combination with giving instructions to the patient and regular fluoride application seems to
be an alternative to the already existing treatment options of carious lesions in deciduous
teeth. The best results are seen with occlusal and shallow lesions. Continue reading →

Objectives: The aim of the present study is to systematically evaluate the current
literature for the effect of ultrasonic devices, ultrasonic scalers in particularly, on
cardiac pacemakers and ICDs to add evidence based knowledge regarding health
ris… Continue reading →

Objective: To evaluate the long-term outcomes of implant-supported maxillary overdenture, of simultaneous implant placement with the alveolar ridge expansion technique in the maxilla with insufficiency of alveolar ridges (SPLIMP) and the oral health –related quality of life (OHRQoL) of these patients.
Materials and methods: 22 patients of the Spaarne Gasthuis in Haarlem and Hoofddorp and the Red Cross Hospital in Beverwijk with insufficiency of alveolar ridges were treated using the SPLIMP technique participated in this study. The OHRQoL was determined by the patients at home. The clinical examination includes evaluation of implants osseo-integration, a X-ray was made to evaluate the bone loss comparing to the first taken X-ray taken after SPLIMP. Paired samples t-test was used to compare means. Also the effect of different bone augmentation materials and a resorbable membrane was evaluated using an ANOVA test.
Results: All implants were osseointegrated and no implant was lost. Regarding the bone loss, no significant differences were found between additional bone augmentation materials and without additional materials, Also no significant difference was found if a resorbable membrane was used.
Conclusions: Within the limitations of this study, SPLIMP has a high survival rate. The procedure seems to be save and predictable. Patients receiving implant-supported maxillary overdenture after SPLIMP have low scores on the OHIP-NL49. Continue reading →

Aim The aim of this research was to investigate the validity and reliability of volume measurements of bone with aid of the cone beam CT scanner. The influence of applied materials, like osteosynthesis screws and sutures, on the measurements was also investigated.
Methods A comparison is made between volume measurements on bone derived from a pig’s jaw created by the cone beam CT scanner and the golden standard. The golden standard consists of applying dental wax on the bone to avoid influx of water. The volume of the bone has been measured according to the water displacement method. A volume of water inside a beaker is compared to the watervolume after adding the bone and filling the beaker to the same level. With these measurements the bone volume can be calculated. 24 pieces of bone were used. On each piece 3 measurements were done, resulting in 72 measurements. To investigate the influence of applied materials, six bone augmentations were simulated. A CBCT scan was made after augmentation, a second CBCT scan was made after detaching the bone block from the augmentation site. The retreived volumes were compared.
Results Most of the volumes retrieved with aid of the CBCT differed significantly (α=0.05) from the measurements according to the golden standard. The measurements turn out the be very reliable. (Pearson correlatie test, r = .991, p = .000.) The influence of applied materials has not been verified in this investigation. (Wilcoxon-Signed Rank Test, z = -1.153, p = .249.)
Discussion The differences between volume measurements are mostly due to the ‘partial-volume’ effect, where voxels wich contain a little bit of bone will account for a completely filled voxel. Any trapped air bubbles during appliance of dental wax will result in a greater deviation of the retreived volumes. An analysis of grey values retreived from a CBCT scan is manually done, so the volume is also influenced by the analist. Conclusion It turns out that a volume measurement determined by the CBCT scanner is very reliable but not valid. The CBCT scanner with the used ‘threshold’ is not useful for determining exact bone volumes. Relative differences before and after bone augmentation can be measured with great reliability. The influence of applied materials like osteosynthesis-screws has not been verified. Continue reading →

Background: Gagging is a natural, protective reflex that occurs when a foreign object threats to come into the oropharynx. The gag reflex can be induced by different types of stimuli and the intensity differs for each individual. A disfunctional, extr… Continue reading →

Purpose: the aim of this systematic review was to compare which bone substitution material has the best effectiveness in increasing the bone or reducing bone resorption after applying in the aveolus immediately after tooth extraction. The purpose of this comparison is to provide an up-to-date overview of the available scientific evidence of the effectiveness of various bone substitution materials for the purpose of alveolar ridge preservation.
Materials and methods: a systematic research is performed to identify and select articles who studied the effectiveness of several bone substitution materials for the purpose of alveolar ridge preservation. The data was compared with the aid of a descriptive analysis, which subdivided the data by measuring method and mean follow-up.
Results: of the 351 identified articles, 18 were included in this systematic review. In the included articles, different bone substitution materials were compared to other bone substitution materials or to control groups where no bone substitution materials were used. The comparison of clinical data revealed that Bio-Oss® has the best effectiveness after 12 weeks to 3 months, that Bio-Oss® + BPAM, CaS + DFDBA and Bio-Oss® + BioGide® have the best effectiveness after 16 weeks to 4 months and that NanoBone® + BioGide® and Bio-Oss® + BioGide® have the best effectiveness after 6 to 7 months. The comparison of radiographic data revealed that Bio-Oss® has the best effectiveness in increasing the radiographic bone density after 12 to 14 weeks and that MGCSH + ConFORM® and CRP + ConFORM® have the best effectiveness in reducing the loss of vertical bone thickness after 3 months. The comparison of histological/histomorphometric data revealed that CRP + ConFORM® have the best effectiveness in increasing the mean percentage of new/vital bone after 12 weeks to 3 months, that MEHA has the best effectiveness in increasing the mean percentage new/vital bone after 16 weeks to 4 months and that NHA + CS and BHA + CS have the best effectiveness in increasing the mean percentage of new/vital bone after 5 to 7 months.
Conclusion: the choice of bone substitution material that has the best effectiveness for alveolar ridge preservation depends on the measuring method and on the time of measuring. It can be concluded that the best time to place dental implants is 4 months after extraction and ridge preservation using Bio-Oss® + BPAM if the aim is the preservation of de clinical horizontal bone thickness. If preservation of the vertical bone thickness is the aim, the best time to place dental implants is 19 weeks after tooth extraction and alveolar ridge preservation with 70% FDBA + 30% DFDBA with d-PTFE membrane. Continue reading →

Background Type of feeding during the first period of a child’s life can play an important role in the development of their oral health. The aim of this review was to give an update of available literature on the influence of breast- and bottle-feeding on the development of caries, erosion and the occlusion in children.
Methods PubMed was searched for relevant studies published until December 2016. All studies including data on breastfeeding and/or bottle-feeding and their influence on the development of caries, erosion and the occlusion, were included. Two independent reviewers assessed the studies’ eligibility and quality, and extracted data from the included studies. Newcastle-Ottawa Scale (NOS) for Assessing the Quality of Nonrandomized Studies in Meta-Analyses was used for quality assessment.
Results At the end of the screening process, 30 studies remained for inclusion: 20 considering caries, 1 considering erosion, and 9 considering occlusion in relation to breast- and bottle-feeding. Breastfeeding was found to have a protective effect on development of caries, but early weaning (24 months) were associated with higher caries experience. In addition, bottle-feeding was found to be associated with higher caries experience. Children who were weaned at an early age ( Continue reading →

Doelstelling: In deze studie is onderzoek gedaan naar 3 verschillende sectionele matrixsystemen op contour- en contactpuntherstel bij klasse II restauraties.
Materiaal en methode: Er zijn in dit onderzoek 3 matrix-systemen getest: het Contact-matrixsysteem, V3-matrixsysteem en het Twinring-matrixsysteem. Met behulp van een kolomboor zijn in 60 KaVo-elementen identieke preparaties gemaakt die in 3 groepen zijn ingedeeld. Per onderzoeksgroep zijn 20 elementen geïncludeerd die at random zijn verdeeld. Groep 1: 20 KaVo elementen gerestaureerd met behulp van het contact-matrixsysteem. Groep 2: 20 KaVo elementen gerestaureerd met behulp van het V3-matrixsysteem. Groep 3: 20 KaVo elementen gerestaureerd met behulp van het Twinring-matrixsysteem. Deze elementen zijn beoordeeld op occluso-gingivale en bucco-linguale contour vanaf buccaal gezien en vanaf occlusaal gezien en vergeleken met een oorspronkelijk, niet-gerestaureerd KaVo-element. Met behulp van een opstelling zijn vanaf een exact identieke positie foto’s gemaakt van de elementen. De foto’s zijn geanalyseerd met behulp van Matlab en meetbaar gemaakt. Tevens is er met een flosdraad gekeken of er een contactpunt is en is er beoordeeld of er sprake is van een contactpunt of een contactvlak.
Resultaten: De gemiddelde bucco-linguale afwijking(uitgedrukt in pixels) met het oorspronkelijke element met hun standaarddeviaties zijn: groep 1(-20,54 ± -6,08) > groep 2(-16,44 ± 4,55) > groep 3(-13,61 ± 4,92). Wat betreft de occluso-gingivale contour zijn de resultaten: groep 1(-19,02 ± 6,06) > groep 3(-14,15 ± 3,11) > groep 2(-13,51 ± 3,26). Het verschil tussen groep 1 in vergelijking met groep 2 en 3 is significant, maar het verschil tussen groep 2 en 3 is niet significant.
De gemiddelde maximale bucco-linguale afwijking in vergelijking met het oorspronkelijke element is: groep 1(-32,85 ± 6,92) > groep 2(-28,10 ± 6,67) > groep 3(-24,15 ± 5,23). Die van de occluso-gingivale contour zijn: groep 1(-35,6±7,34) > groep 2(-32,35 ± 4,99) > groep 3(-30,50 ± 3,47). Hierbij is het verschil tussen groep 1 en 3 wel significant maar de andere verschillen niet.
Bij alle restauraties is een contact gecreëerd met het buurelement. Bij de meeste restauraties is een contactvlak gevormd(61,67%) bij de overige elementen is een contactpunt gecreëerd(38,33%). In groep 1 komt het vaakst een contactvlak voor(85%). Bij de andere 2 groepen is dit respectievelijk 45% en 55%.
Conclusie: Bij gebruik van alle drie sectionele matrixsystemen wordt contact gecreëerd met het buurelement. Restauraties met behulp van het V3-matrixsysteem en het Twinring-matrixsysteem zorgen voor een beter contour herstel dan bij het gebruik van het contact-matrixsysteem. Echter zorgt deze laatste voor strakkere contactpunten.
Trefwoorden: Sectionele matrixsystemen, Twinring-matrixsysteem, V3-matrixsysteem, contact-matrixsysteem, contour, contactpunt. Continue reading →