The following possibilities are possible if tone is ignored:Īllophonic labial-velars are known from Vietnamese, where they are variants of the plain velar consonants /k/ and /ŋ/. For example, Eggon contrasts /bɡ/, /ɡb/, and /ɡ͡b/.
These sounds are clearly single consonants rather than consonant clusters. Labial–velar stops and nasals also occur in Vietnamese but only word-finally. The Yele language of Rossel Island, Papua New Guinea, has both labial–velars and labial–alveolar consonants. Floyd (1981) reports a voiceless implosive from Igbo. Labial–velar stops also occur as ejective and implosive (often transcribed ⟨ ɡ͡ɓ⟩). In Southeast Asia, they occur in the Adu dialect of Nuosu (Yi), which aside from its isolated location, is unusual in having a relatively large inventory of labial-velar consonants, including the rare aspirated version: /k͡pʰ, k͡p, ɡ͡b, ᵑɡ͡b, ŋ͡m/. Phonemic labial–velars occur in the majority of languages in West and Central Africa (for example in the name of Laurent Gbagbo, former president of Ivory Coast they are found in many Niger–Congo languages as well as in the Ubangian, Chadic and Central Sudanic families), and are relatively common in the eastern end of New Guinea. The order of the letters in ⟨ k͡p⟩ and ⟨ ɡ͡b⟩ is therefore not arbitrary but motivated by the phonetic details of the sounds. While 90% of the occlusion overlaps, the onset of the velar occurs slightly before that of the labial, and the release of the labial occurs slightly after that of the velar so the preceding vowel sounds as if it were followed by a velar, and the following vowel sounds as if it were preceded by a labial. To pronounce them, one must attempt to say the velar consonants but then close their lips for the bilabial component, and then release the lips. There is no reliable evidence to show a benefit of one type of veneer restoration (direct or indirect) over the other with regard to the longevity of the restoration.Truly doubly articulated labial-velars include the stops and the nasal.
#LABIAL VEEER LAM TRIAL#
Although the trial met the review's inclusion criteria with regard to participant characteristics, interventions and outcomes assessed, problems with the reporting of the data prevented any statistical analysis of the results.
#LABIAL VEEER LAM FULL#
Six full publications were screened as being potentially relevant to the review, only one trial was found to meet the review's inclusion criteria. Authors of the primary studies were contacted to provide additional information as necessary. The primary outcome was restoration failure.Īssessment of relevance and validity and data extraction were conducted in triplicate. The indirect restorations may be either composite or porcelain. There was no restriction on language.Īll randomised controlled trials (RCTs) of participants with permanent anterior teeth suitable for restorations using laminate veneers, comparing direct (different composite materials) and indirect techniques for making dental veneers. The following electronic databases were searched: The Cochrane Oral Health Group's Trials Register, The Cochrane Central Register of Controlled Trials (CENTRAL), (The Cochrane Library Issue 3, 2002), MEDLINE (1980 to ) and EMBASE (1980 to ). To examine the effectiveness of direct versus indirect laminate veneer restorations. The veneer acts as a thin layer of a material covering the labial surface of a tooth and can be applied directly to the tooth, or by using indirect methods. For teeth that are sound, this might include the use of a veneer restoration. Patients with discoloured teeth frequently present to the dentist requesting restorations designed to improve their appearance.
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