Near visual acuity of dental hygienists with and without magnification.

OBJECTIVES: The aim of this study was (i) to evaluate the visual performance of dental hygienists in their clinical environment and (ii) to analyse the relationship between self-assessed and objectively measured visual acuity. METHODS: The near visual acuity of 191 dental hygienists and dental hygiene students was self-assessed with a visual analogue scale and objectively measured with miniaturized visual tests in a simulated clinical setting. The visual acuity was also measured with magnification aids if they were part of the individual clinical equipment. The influence of age and magnification on the near visual acuity was analysed. RESULTS: The visual performance with respect to dental working distance showed a variability of 300% in the dimension of the smallest recognized structure. A weak positive correlation between the self-assessed and objectively measured visual performance (Spearman's rank correlation = 0.27) and a highly significant impact of the test person's age and the use of loupes (both P < .0001) were found. Test subjects ≥40 years exhibited a similar visual acuity when using loupes compared to the visual acuity of test subjects <40 years without loupes. CONCLUSIONS: The visual performance with respect to dental working distance cannot be self-assessed and varies individually. Dental hygienists and students of dental hygiene with a weak near visual acuity were not aware of their deficiencies. Optical aids should be used to compensate for individual visual deficiencies and are mandatory above an age of 40 years due to the effects of presbyopia.

The timing of extraction of non-restorable first permanent molars: a systematic review.

AIM: To identify the ideal timing of first permanent molar extraction to reduce the future need for orthodontic treatment. MATERIALS AND METHODS: A computerised database and subsequent manual search was performed using Medline database, Embase and Ovid, covering the period from January 1946 to February 2013. Two reviewers (JE and ME) extracted the data independently and evaluated if the studies matched the inclusion criteria. Inclusion criteria were specification of the follow-up with clinical examination or analysis of models, specification of the chronological age or dental developmental stage at the time of extraction, no treatment in between, classification of the treatment result into perfect, good, average and poor. The search was limited to human studies and no language limitations were set. RESULTS: The search strategy resulted in 18 full-text articles, of which 6 met the inclusion criteria. By pooling the data from maxillary sites, good to perfect clinical outcome was estimated in 72% (95% confidence interval 63%-82%). Extractions at the age of 8-10.5 years tended to show better spontaneous clinical outcomes compared to the other age groups. By pooling the data from mandibular sites, extractions performed at the age of 8-10.5 and 10.5-11.5 years showed significantly superior spontaneous clinical outcome with a probability of 50% and 59% likelihood, respectively, to achieve good to perfect clinical result (p<0.05) compared to the other age groups (<8 years of age: 34%, >11.5 years of age: 44%). CONCLUSION: Prevention of complications after first permanent molars extractions is an important issue. The overall success rate of spontaneous clinical outcome for maxillary extraction of first permanent molars was superior to mandibular extraction. Extractions of mandibular first permanent molars should be performed between 8 and 11.5 years of age in order to achieve a good spontaneous clinical outcome. For the extraction in the maxilla, no firm conclusions concerning the ideal extraction timing could be drawn.

The impact of rapid palatal expansion on children's general health: a literature review.

AIM: The original indication for rapid palatal expansion was to treat skeletal maxillary constriction. As positive effects were clinically proven, the number of indications for rapid palatal expansion has continuously grown. The purpose of the present article was to review the literature and to evaluate the effect of rapid palatal expansion on nose breathing, natural head position, obstructive sleep apnoea syndrome, nocturnal enuresis and conductive hearing loss. CONCLUSION: It can be concluded that rapid palatal expansion is predominantly recommended in children with maxillary constriction. In those with normal occlusion, maxillary expansion can be considered as the really last choice of treatment when other treatment options in patients with nose breathing, obstructive sleep apnea syndrome (OSAS), nocturnal enuresis and conductive hearing loss (CHL) have failed. Therefore, collaboration between paediatricians, otolaryngologists, paediatric dentists and orthodontists will lead to the best treatment outcomes in the future.

Effect of Magnification on the Precision of Tooth Preparation in Dentistry.

OBJECTIVES: To evaluate the impact of magnification aids on the precision of tooth preparation under simulated clinical conditions. METHODS AND MATERIALS: Two plastic blocks marked with a geometric shape were fixed in a dental phantom head: a circle as the distal surface of tooth 16 (UNS 3) and a y-shaped figure as the occlusal surface of tooth 36 (UNS 19). Sixteen dentists (mean age: 39 years; range: 26-67 years) prepared the geometric shapes from the inside to the boundary line with a cylindrical bur and water-cooling. The boundary line had to be touched but not erased. Chair-side assistance was provided to simulate the clinical situation. Tooth 16 was prepared under indirect vision via a dental mirror. Tooth 36 was prepared under direct vision A) without magnification aids, B) with Galilean loupes, 2.5× and light-emitting diode light, and C) with a microscope, 6.4× and coaxial light. The preparation procedure was performed three times in different sequences of the magnification devices and with a break of at least 1 week between each procedure. The correctly prepared contour and the incorrectly prepared areas were evaluated in relation to the whole circumference of the geometric shapes. RESULTS: For both values the precision was significantly higher when a microscope was used, followed by preparation using loupes; precision was lowest without magnification aids ( p<0.0001). This was true for both indirect and direct vision ( p<0.05). CONCLUSIONS: Magnification devices improved the precision of tooth preparation under simulated clinical conditions.

A Near Visual Acuity Test for Dentists.

Unimpaired near vision is crucial in dentistry, but appropriate visual tests at dental working distance are not publicly available. The aim of this study was to validate a novel visual triage test for dentists that is easy to use and freely available. The near visual acuity at 300 mm of 106 dental professionals (aged 21-65 years) was assessed with 1) a validated near visual test for scientific purposes miniaturized on a microfilm; 2) an experimental test using a US $5 bill, in which the first five words of each line in the Lincoln Memorial frieze had to be read under a dental operating light. The Spearman rank correlation coefficient of 0.784 revealed a strong correlation between the two tests (p<0.0001). The ability to read six or more words in the memorial frieze meant there was a 94% chance of having a validated near visual acuity greater than or equal to the median score of the dentists tested. If none of the words could be read, the chance of having a near visual acuity below the median of the peer group was 89%. The influence of the dentists' age and experience on their visual performance reported in former studies was corroborated with this new test. The US $5 bill offers a simple and easily available near visual test to rank individuals' near vision relative to that of other dentists and to recognize the progression of presbyopia with increasing age.

Visual Acuity and Experience with Magnification Devices in Swiss Dental Practices.

OBJECTIVES: The aims of the present study in Swiss dental practices were 1) to provide an update on the prevalence of different magnification devices, 2) to examine the relationship between self-assessed and objectively measured visual acuity, and 3) to evaluate the visual performance of dentists in the individually optimized clinical situation of their respective practices. METHODS AND MATERIALS: Sixty-nine dentists from 40 randomly selected private practices (n=20, <40 years; n=49, ≥40 years) participated in the study. A questionnaire was provided to evaluate the self-assessed near visual acuity and the experience with magnification devices. The objective near visual acuity was measured under standardized conditions on a negatoscope. The clinical situation, including the use of habitual optical aids, was evaluated with visual tests on a phantom head. RESULTS: A total of 64% of the dentists owned a dental loupe: 45% Galilean loupes, 16% Keplerian loupes, and 3% single lens loupes. In total, 19% of the questioned dentists owned a microscope in addition to the loupes. The correlation between the self-assessed and the objective visual performance of the dentists was weak (Spearman rank correlation coefficient=0.25). In the habitual clinical situation, magnification devices (p=0.03) and the dentist's age (p=0.0012) had a significant influence on the visual performance. CONCLUSIONS: Many dentists were not aware of their visual handicaps. Optical aids such as loupes or microscopes should be used early enough to compensate for individual or age-related visual deficiencies.